Authoring a Plugin

This is the canonical developer entry point for Kandev runtime plugins. Use it to choose a supported surface, edit manifest.yaml, implement the backend or native UI, package it, and test it against a disposable development instance. The plugin manifest reference owns field-by-field schema details; Plugins covers operator installation and lifecycle.

The official scaffold is kdlbs/kandev-plugin-template. Production plugins live in their own repositories. The in-tree fixture is test support, not a starter repository.

Quick workflow

1. Choose the closest recipe in this page.
2. Copy the template and edit manifest.yaml: identity, runtime executable, UI paths, capabilities, events, webhooks, and config.
3. Implement only through the Go pluginsdk and the frontend registry/Host API.
4. Run the plugin repository tests, vet/lint, and build.
5. Stage the package, run plugin-pack, inspect the archive and generated checksums, then install it in a disposable Kandev instance.
6. Smoke-test every declared hook and capability, then bump the version for the next iteration.

Lifecycle

flowchart LR
  A[Package install] --> B[Manifest and package validation]
  B --> C[Safe extraction]
  C --> D[Runtime subprocess]
  D <-->|Host gRPC over go-plugin| E[Go plugin backend]
  C --> F[Frontend bundle and styles]
  F --> G[Browser bundle loading]
  G --> H[registerKandevPlugin initialize]

Installation validates the manifest, archive paths, checksums, managed runtime, and the current host executable before extraction. Kandev then supervises the declared subprocess and injects a Host connection. Installing a new version does not remove the one it replaces: that version stays on disk as the rollback target, and only the versions before it are deleted, once the new one is confirmed running. Two extracted versions is therefore the steady state for a plugin that runs; a plugin that is disabled or failed to start keeps every version it has, and data/ is never part of that cleanup. The UI bundle is static package content loaded by the browser; it does not run inside the backend subprocess. On disable or uninstall, the host calls destroy when present and bulk-revokes registrations, styles, routes, handlers, and navigation. Reloads and updates are generation-safe: a slow or failed initialization is not treated as a definitive revocation, while a successfully ready generation can remove panels it no longer registers. Each attempted generation owns its requests, subscriptions, modals, task-link dialogs, toasts, and review surfaces. Timeout, failure, reload, disable, or uninstall aborts and cleans those resources before calling destroy exactly once; late callbacks from an expired generation are fenced from host state.

Package and data layout

<id>-<version>.tar.gz
├── manifest.yaml                         # required, validated first
├── server/
│   └── plugin-<goos>-<goarch>[.exe]      # one or more declared binaries
├── ui/
│   ├── bundle.js                          # optional native ES module
│   ├── plugin.css                         # optional styles
│   └── assets/                            # optional files referenced by UI
├── assets/                                # optional manifest icon/assets
├── checksums.txt                          # generated by plugin-pack
└── checksums.txt.sig                      # optional signature

runtime.executables maps a platform key such as linux-amd64 to a clean package-relative path such as server/plugin-linux-amd64. Windows values must end in .exe. The host platform's key must be present at install time. A UI-focused plugin still ships a managed backend executable because the current installer requires runtime.type: binary; that executable can be a no-op pluginsdk.UnimplementedPlugin server.

Kandev injects KANDEV_PLUGIN_DATA_DIR into the subprocess. It is the durable, per-plugin directory for arbitrary files or a plugin-owned database:

~/.kandev/plugins/<id>/data/

The directory is shared across installed versions, survives restarts and upgrades, and is removed on uninstall. Keep small structured values in Host state instead, and never write arbitrary files elsewhere in the Kandev data directory.

Choose a plugin shape

There is no separate HTTP server to launch. pluginsdk.Serve owns the go-plugin/gRPC handshake and Host injection. The backend implements pluginsdk.Plugin (OnEvent and/or HandleWebhook) and embeds pluginsdk.UnimplementedPlugin for no-op defaults.

Contribute an agent tool

A managed plugin can contribute task-aware MCP tools through the same supervised gRPC process. Add an agent_tools declaration to manifest.yaml and implement the optional pluginsdk.AgentToolPlugin interface:

agent_tools:
  - name: add_tag
    description: Add an existing tag to the current task.
    surfaces: [kanban-task]
    input_schema:
      type: object
      properties:
        tag_id: { type: string }
      required: [tag_id]
      additionalProperties: false
    annotations:
      read_only_hint: false
      destructive_hint: false
      idempotent_hint: true

The host exposes the readable canonical name kandev_<plugin-id-slug>_<local-name> (for example, kandev_task_tags_v1_add_tag). Punctuation in the stable plugin ID becomes an underscore. Very long names receive a short stable hash suffix after the slug is truncated. Tool names are host-owned; the plugin-local name is used for the gRPC dispatch.

Tools may target kanban-task, office-task, or both. They are not exposed to configuration or external MCP clients. Kandev validates the input and optional output JSON Schemas, supplies task/session/workspace/surface context, enforces a 30-second deadline and 1 MiB result limit, and does not retry calls.

The optional SDK method is:

InvokeAgentTool(context.Context, *pluginsdk.AgentToolRequest) (*pluginsdk.AgentToolResult, error)

The request includes immutable invocation, task, session, workspace, and surface context. Return required fallback text, optional structured content, and IsError when the operation failed. Declaring a tool does not grant Host API capabilities; use the existing capabilities fields for those permissions.

Security and capabilities

Plugins are privileged installed code. The capability list gates Host RPCs; it is not an operating-system sandbox. A backend subprocess inherits the Kandev process environment, and a UI bundle runs as same-origin JavaScript with the curated React, UI, and app-store surface.

• Plugins do not receive direct database access. Use typed Host readers/writers, Host state, secrets, events, and the data directory. Do not import Kandev internal/... packages or call undocumented REST endpoints.
• state gates Host state; secrets gates RevealSecret and plugin-owned secret methods; each api_read resource gates its reader; api_write gates task/message mutations and interaction responses; agent_invoke gates utility-agent calls; and capabilities.events controls event delivery.
• GetConfig and EmitEvent are ungated. GetConfig returns this plugin's own config, including cleartext secret fields, so do not log or commit it.
• Declared webhook keys default to public. Set webhooks[].access: authenticated for browser UI and billable operations. Kandev does not enforce webhooks[].method; public integrations must still validate the provider signature and replay/timestamp rules before side effects.
• An authenticated webhook is reachable from your panel with any method, GET included: host.api.fetch is same-origin (or carries an accepted Origin in a split-origin install), which is what the host checks. You do not need to force a read onto POST.
• capabilities.auth is the highest-risk capability. A webhook response may assert a verified external identity with X-Kandev-Auth-Login; only assert an email the IdP verified as owned by the subject. See ADR 0050.

Storage decision table

Host state is not host.storage: Host state is plugin-scoped backend state with no transaction primitive, so design updates to be idempotent; host.storage (below) is per-user, per-scope frontend storage with an optional ifUnmodifiedSince compare-and-swap.

Authoritative contracts

The guide summarizes the contract for discovery. These files remain the source of truth and must be updated together when the contract changes:

• Versioned frontend author contract: @kandev/plugin-sdk, sourced from apps/packages/plugin-sdk. Import it with import type; the package has no dependency on Kandev, React, Zustand, or private @/ modules, so it also typechecks when consumed from an isolated or sparse checkout.
• Frontend host implementation: docs/plans/plugins/PLUGIN-API.md and apps/web/lib/plugins/types.ts. These may contain compatibility-only host details that are deliberately absent from the public SDK.
• Concrete frontend Host exports: apps/web/lib/plugins/host-api.ts.
• Backend author API: apps/backend/pkg/pluginsdk.
• Wire contract: apps/backend/proto/kandev/plugin/v1/plugin.proto.
• Manifest model and semantic validation: apps/backend/internal/plugins/manifest.
• Package integrity and installation: apps/backend/internal/plugins/pkgtar.
• Durable decisions: ADR 0043, ADR 0047, ADR 0048, and ADR 0050.

Frontend contract

Loading and cleanup

The package's ui.bundle is a hand-written ES module. When active, Kandev loads it and the bundle calls:

window.registerKandevPlugin("my-plugin", {
  initialize(registry, host) {},
  destroy() {},
});

initialize receives a registry scoped to this plugin and a PluginHostApi. The host may call initialize more than once across disable/enable cycles. Make it repeatable; return a cleanup function from subscriptions and timers, and use destroy to remove side effects that are not registrations. The host revokes all registry entries, closes plugin modals, and removes plugin styles on disable/uninstall. Reloads can temporarily leave a plugin in a loading or failed state; open and saved panels remain until the current generation is ready. A ready generation that no longer registers a panel closes it, while an explicit disable or uninstall closes every panel owned by the plugin. This lifecycle bookkeeping is host-internal; plugins do not call lifecycle methods.

Type frontend bundles against the versioned, runtime-free SDK rather than copying host interfaces or importing Kandev application files:

import type { PluginHostApi, PluginRegistry } from "@kandev/plugin-sdk";

Official code-host plugins use host.context for provider-neutral workspace, task-creation, and exact repository-identity reads. getWorkspaceIds() and subscribeWorkspaces() let a plugin republish workspace-scoped integration state after load or when the workspace list changes. If a required read is missing, extend this typed context contract; do not reverse-engineer Zustand slice shapes in a released plugin.

Frontend hook/API matrix

Code-host integration surface map

A code-host plugin should be a normalized provider adapter, not a parallel copy of Kandev's GitHub UI. The plugin owns remote API calls, authentication, provider identifiers, and normalized snapshots. Kandev owns the interaction patterns, responsive layout, status colors, dialogs, menus, and review chrome.

The task indicator uses the same semantic precedence as first-party providers: failures and requested changes are red, pending checks yellow, an outstanding review with passing checks sky blue, passing checks green, merged reviews purple, and neutral or draft reviews muted. Publish semantic state only; never send CSS classes or provider-selected colors.

Persist links, suppressions, task reservations, and watches by provider ID, provider connection scope, immutable repository ID, and change-request number. Repository names, paths, clone URLs, and human-readable review keys can change or be reused, so use them only for display and live lookup. Bind watch state and OAuth refresh work to an opaque connection epoch; replacement or disconnect must fence in-flight results, while an explicit resume may bind a watch to the new epoch.

Keep refresh(taskId) lightweight: publish metadata, reviewers, checks, and an inexpensive comment count when available. Load files, diffs, commits, and comment bodies from ReviewPanel only when the user opens Review. Bound every provider page and action response, and expose truncation rather than overflowing Kandev's response limit.

Repository listing callbacks receive optional query, opaque cursor, limit, and signal fields. Return { repositories, nextCursor } for a page; returning an array remains compatible for small or older providers. Treat cursors as provider-owned opaque values, bind them to the original query, and stop emitting nextCursor when exhausted. Include immutable repository identity and provider connection scope in that binding; reject a mismatched cursor before making a remote request. Kandev follows pages and fails a repeated cursor instead of looping forever.

Localize plugin UI

Register an English fallback before registering labels or rendering routes. Catalogs are flat, plugin-scoped, and support {{name}} interpolation plus _one/_other plural keys. Use the reactive hook in components and the imperative translator in registry getters so a locale change updates native navigation and provider labels without reloading the plugin.

registry.registerTranslations({
  en: {
    pullRequests: "Pull requests",
    linkedCount_one: "{{count}} pull request linked",
    linkedCount_other: "{{count}} pull requests linked",
  },
  "pt-pt": {
    pullRequests: "Pull requests",
    linkedCount_one: "{{count}} pull request associado",
    linkedCount_other: "{{count}} pull requests associados",
  },
});

const translate = host.i18n.t;
registry.registerNavItem({
  id: "reviews",
  get label() {
    return translate("pullRequests");
  },
  path: "/reviews",
});

function ReviewsPage() {
  const { t } = host.i18n.useTranslation();
  return host.jsx("h1", null, t("pullRequests"));
}

Own provider brand icons

Icon fields accept a curated host icon name or a plugin-owned component. Keep provider brands in the plugin repository so a new code host does not require a Kandev icon-map change. Build the component with host.jsx; do not bundle React.

const AcmeIcon = ({ className }: { className?: string }) =>
  host.jsx(
    "svg",
    { viewBox: "0 0 24 24", className, "aria-hidden": true },
    host.jsx("path", { d: "M4 12h16" }),
  );

registry.registerRepositoryProvider({
  id: "acme",
  label: "Acme",
  icon: AcmeIcon,
  // listRepositories, listBranches, and inspectURL omitted here
});

Kandev accepts only supported host locale IDs, at most 1,000 messages per locale, safe flat keys, and messages up to 4,096 characters. An invalid replacement is rejected before the active catalog changes. Do not translate provider identifiers, action keys, URL paths, or other machine-readable state.

For a plugin-owned workbench, use host.ui.IntegrationRepositoryFilter and host.ui.IntegrationCursorPagination; they preserve the same searchable picker, pagination geometry, touch targets, and responsive behavior as first-party code-host pages without requiring a plugin to copy their markup.

The examples below were captured from an isolated packaged-plugin run. The provider data is fictional; the surrounding controls are the production host-owned components.

Provider dashboard and repository picker

The plugin route composes the shared dashboard primitives, while the declared repository provider appears inside Kandev's existing task dialog.

Link a pull request from a task

registerTaskAction contributes only the provider entry. The host owns the parent Link menu and the link dialog.

Task status, CI, and review

Association and review snapshots drive every surface. In this example, passing CI plus one outstanding reviewer makes the task icon sky blue; hovering it shows the same normalized summary used by first-party providers.

Composer reference search

Dynamic reference_sources appear beside built-in sources. A selected result is display-only until Kandev calls the plugin again to authorize it for submission.

Supported named slots

registerComponent currently has these mounted slots. The source type is open to strings, but an unmounted name renders nowhere.

AppStatusBarSlotProps is { placement, presentation, density, pathname, activeWorkspaceId, activeTaskId, activeSessionId }. Desktop presentation is a compact 24px bar; mobile presentation is an in-flow drawer, so render a touch-usable row. Status items can be reordered by the host; plugins do not get an ordering API.

SidebarWorkspaceActionsSlotProps is { workspaceId, workspaceLabel?, presentation }. The host uses presentation: "desktop" for the compact sidebar cluster and presentation: "mobile" for the phone navigation sheet. Mobile actions must keep their own buttons or links at least 44px in the active dimension and provide an accessible name.

PluginComposerSlotProps is { surface, presentation, taskId, taskTitle?, activeSessionId, sessionIds, disabled, submittable, disabledReason?, composer }. The composer capability provides insertText, focus, and asynchronous submit; submit returns submitted only when the native composer accepts the operation, otherwise blocked or unavailable.

Backend contract

Plugin lifecycle surface

Event delivery is best-effort: Kandev makes the initial attempt plus retries with 5s, 15s, and 45s delays, and a bounded in-memory queue/error buffer can drop events during sustained overload or restart. Use EventID for deduplication and a source-of-truth reconciliation path when loss matters. The full subscription vocabulary and wildcard rules are in the manifest reference.

Host API matrix

The Go signatures, filters, DTOs, and pagination types live in apps/backend/pkg/pluginsdk/host.go and data_types.go. api_write task/message methods are implemented in the current branch; do not repeat older docs that call them reserved.

Host calls are request-scoped rather than registrations: pass the handler context, handle cancellation, and close any files or external clients created by the plugin. There is no Host cleanup callback. Typical calls are host.SetState(ctx, "task", taskID, "note", value), host.Tasks().List(ctx, filter, page), host.Tasks().Create(ctx, pluginsdk.CreateTaskInput{...}), host.Messages().Send(ctx, taskID, sessionID, text), and host.InvokeUtilityAgent(ctx, prompt); each fails with PermissionDenied when its manifest capability is absent.

Task-oriented recipes

The snippets below are deliberately small. Keep the full template Makefile and release workflow from the official scaffold.

The maintained in-tree fixture shows the same surfaces end to end: its Go backend, manifest, and native bundle are the source examples used by the package and browser tests.

1. UI-focused plugin

Use a no-op backend because the managed installer requires a host executable.

# manifest.yaml
id: "acme-dashboard"
api_version: 1
version: "0.1.0"
display_name: "Acme Dashboard"
runtime:
  type: binary
  executables:
    linux-amd64: server/plugin-linux-amd64
ui:
  bundle: "/ui/bundle.js"

// server/main.go
package main

import "github.com/kandev/kandev/pkg/pluginsdk"

func main() { pluginsdk.Serve(&pluginsdk.UnimplementedPlugin{}) }

// ui/bundle.js
window.registerKandevPlugin("acme-dashboard", {
  initialize(registry, host) {
    function Page() {
      return host.jsx("main", null, "Acme dashboard");
    }
    registry.registerRoute("/acme-dashboard", Page);
    registry.registerNavItem({
      id: "home",
      label: "Acme",
      path: "/acme-dashboard",
      icon: "chart",
    });
  },
});

2. Go backend with Host state

type Plugin interface {
	// OnEvent handles a single bus event delivery. A non-nil error causes
	// kandev to retry (3 retries, 5s/15s/45s backoff).
	OnEvent(ctx context.Context, e *Event) error

	// HandleWebhook handles an inbound request relayed from
	// POST /api/plugins/{id}/webhooks/{key}.
	HandleWebhook(ctx context.Context, req *WebhookRequest) (*WebhookResponse, error)
}

Embed pluginsdk.UnimplementedPlugin and override only the methods you need It is a no-op base that also implements HostSetter, so Serve injects a live Host into your plugin once the broker connection back to kandev is established (retrieve it later via p.Host()).

Webhooks

Declare each webhook key in manifest.yaml. Kandev relays GET and POST requests for /api/plugins/<id>/webhooks/<key> to HandleWebhook; undeclared keys return 404. Request bodies are limited to 4 MiB and requests that exceed the limit return 413 before reaching the plugin. Kandev does not authenticate webhook callers or enforce the manifest's informational method, so validate the HTTP method and the upstream provider's signature before any side effect.

The Host API

A plugin calls back into kandev through the injected Host:

type Host interface {
	GetState(ctx context.Context, scope, scopeID, key string) (value map[string]any, found bool, err error)
	SetState(ctx context.Context, scope, scopeID, key string, value map[string]any) error
	DeleteState(ctx context.Context, scope, scopeID, key string) error
	ListState(ctx context.Context, scope, scopeID string) ([]StateEntry, error)

	// GetConfig returns the plugin's own operator-editable config (set via
	// Settings > Plugins > <plugin>, generated from manifest config_schema).
	// Ungated: always readable, secret values included. Kandev restarts a
	// running plugin when its config changes, so re-read at startup.
	GetConfig(ctx context.Context) (map[string]any, error)

	// GetSecret/SetSecret/DeleteSecret manage a plugin-owned secret in
	// kandev's encrypted vault, namespaced to this plugin. Require the
	// `secrets` capability.
	GetSecret(ctx context.Context, key string) (value string, found bool, err error)
	SetSecret(ctx context.Context, key, value string) error
	DeleteSecret(ctx context.Context, key string) error

	// RevealSecret resolves an operator-provided secret reference (e.g. a
	// config value pointing at a shared kandev secret) to its cleartext
	// value. For secrets the plugin itself owns, use GetSecret/SetSecret.
	RevealSecret(ctx context.Context, ref string) (string, error)

	EmitEvent(ctx context.Context, name string, payload map[string]any) error

    // Tasks/Sessions/Workspaces/Workflows/AgentProfiles/Repositories return
	// Host data accessors. List/Get operations require their own api_read
	// resource; task Create/Update/Move require api_write:tasks.
	Tasks() TaskReader
	Sessions() SessionReader
	Workspaces() WorkspaceReader
	Workflows() WorkflowReader
	AgentProfiles() AgentProfileReader
	Repositories() RepositoryReader

	// Messages.List reads historical content (api_read:messages); Send
	// delivers a user prompt through the task session (api_write:messages).
	Messages() MessageReader

	// InvokeUtilityAgent runs a one-shot completion using this plugin's
	// selected utility agent (capability agent_invoke). No API key of your
	// own; FailedPrecondition when no valid enabled agent is selected.
	InvokeUtilityAgent(ctx context.Context, prompt string) (string, error)
}

Executor profiles are an additive, optional Host extension so older Host implementations remain source-compatible. Discover it through the SDK helper:

profiles, ok := pluginsdk.ExecutorProfiles(host)
if ok {
	items, page, err := profiles.List(ctx, pluginsdk.Page{})
	// handle items, page, and err
}

Declare api_read: ["executor_profiles"] before using this reader. A host that does not implement the extension returns ok == false; an implemented reader without the capability returns PermissionDenied from List.

Pending agent interactions are an additive, optional Host extension too; discover it the same way with pluginsdk.Interactions(host). See "Pending agent interactions" below for the contract.

Host state is a small key/value store kandev keeps for your plugin in its own database. Each entry is addressed by a (scope, scopeID, key) triple and holds a JSON object (map[string]any): SetState upserts one, GetState reads it back (found is false when the key was never set), DeleteState removes it, and ListState returns every entry under a (scope, scopeID). Values are JSON objects, not bare scalars; wrap a number as map[string]any{"n": 3}. State is namespaced per plugin (kandev injects your plugin id server-side, so no plugin can read or write another's), survives restarts, is captured by kandev's database backups, and is deleted when the plugin is uninstalled. Reach for it when you want kandev to durably remember something small and structured for you; use the writable data directory below for arbitrary files you'd rather manage yourself.

scope partitions that store by what a value belongs to: instance (the whole kandev instance; scopeID empty), or workspace / task / agent with scopeID set to that entity's id. A per-task counter, for example, is SetState(ctx, "task", taskID, "count", map[string]any{"n": 3}); kept separate from every other task's.

EmitEvent publishes plugin.<your-plugin-id>.<name> on kandev's internal event bus for delivery to any subscriber (including other plugins).

The data-reader accessors return typed, paginated readers, for example host.Tasks().List(ctx, TaskFilter{...}, Page{Limit: 50}) returns ([]Task, *PageInfo, error) with an opaque PageInfo.NextCursor for the next page. See pkg/pluginsdk/data_types.go for the full Task, Workspace, Workflow, WorkflowStep, AgentProfile, Repository, Session, Message, and filter/page types.

host.Messages().List(ctx, MessageFilter{...}, Page{...}) reads historical conversation content (capability api_read:messages). Filter by SessionIDs, TaskIDs, a Since/Until created_at window (RFC3339; Since inclusive, Until exclusive, the natural way to fetch "yesterday"), and message Types. Each Message carries id, session_id, task_id, turn_id, author_type (user or agent), content, type, and created_at. content has kandev's injected <kandev-system> blocks stripped; a plugin never sees raw system prompts.

Pending agent interactions

An agent sometimes stops and waits for a person: a tool-permission request, or a structured question bundle. If your plugin surfaces attention (an inbox, a notifier, a dashboard badge), read that from the interaction API rather than from session state. WAITING_FOR_INPUT also describes an ordinarily completed turn, so a plugin that branches on state alone tells people they owe an answer they do not.

interactions, ok := pluginsdk.Interactions(host)
if !ok {
    // Host predates the interaction API.
    return nil
}
pending, _, err := interactions.ListPending(ctx, pluginsdk.InteractionFilter{
    TaskIDs: []string{taskID},
}, pluginsdk.Page{Limit: 50})

Each Interaction carries ID (the pending id every response keys on), Kind (permission or clarification), the task, session and turn ids, a normalized Status, timestamps, and everything needed to render a valid response: Options for a permission, Questions (each with its own options) for a clarification bundle. AgentDisconnected marks a still-pending clarification whose original waiter went away; it remains answerable, and answering it resumes the session in a new turn, so do not treat it as resolved.

Interactions().Get(ctx, id) resolves any interaction, including resolved ones. That is how an event-driven cache reconciles: an id from an event you replayed or a snapshot you took before a restart still resolves to its current state instead of vanishing.

Responding requires api_write: ["interactions"] and goes through the same services the native UI drives, so the agent actually unblocks:

_, err := interactions.RespondToPermission(ctx, pluginsdk.PermissionResponse{
    InteractionID: interaction.ID,
    OptionID:      interaction.Options[0].OptionID,
})

OptionID must name one of the interaction's declared options; Kandev derives the approve/deny outcome from that option's Kind, so you cannot report an outcome the agent never offered. Set Cancelled: true (with an empty OptionID) to dismiss the request instead. AnswerClarification takes one answer per question in the bundle; CancelClarification(ctx, id, reason) declines the bundle on the user's behalf and works whether or not the original waiter is still parked.

Writes are terminal-once. The first response wins; a later attempt against an already-resolved interaction returns gRPC FailedPrecondition, and an unknown id returns NotFound. Branch on those two to tell "someone else answered first" apart from "my cached id is stale". Do not retry a FailedPrecondition.

host.InvokeUtilityAgent(ctx, prompt) runs a one-shot, non-interactive LLM completion using the utility agent selected for this plugin in Settings > Plugins > <plugin> (capability agent_invoke), and returns its text. Declare the selector in manifest.yaml:

capabilities:
  agent_invoke: true

config_schema:
  type: object
  properties:
    utility_agent:
      type: string
      format: utility-agent
      title: Utility Agent
      description: Agent used for this plugin's LLM calls
  required: ["utility_agent"]

The picker displays configured built-in and custom agent names but stores the selected agent's stable ID. Omit utility_agent from required only when the plugin supports operating without LLM delegation; optional selectors include a Not set choice. The plugin needs no provider API key because it delegates to a kandev-configured agent. A missing, deleted, or disabled selection returns gRPC FailedPrecondition, so handle that as "ask the operator to configure one" rather than a transient failure. This is the LLM step behind, e.g., a "summarize yesterday" plugin: read the conversation with host.Messages(), then summarize it with host.InvokeUtilityAgent(...).

Capability gating. Every Host RPC except GetConfig and EmitEvent is checked against your manifest's capabilities before the handler runs: GetState/SetState/DeleteState/ListState require capabilities.state: true; GetSecret/SetSecret/DeleteSecret/ RevealSecret require capabilities.secrets: true; InvokeUtilityAgent requires capabilities.agent_invoke: true; each data-reader accessor requires its resource in capabilities.api_read (e.g. tasks, sessions, messages, interactions, workspaces, workflows, agent_profiles, repositories). Calling one without the declared capability returns gRPC PermissionDenied with a message naming the missing capability; declare what you use.

Live Host writes

api_write is live, not advisory. Declare only the exact resource you mutate: api_write: ["tasks"] enables host.Tasks().Create(ctx, CreateTaskInput{...}), .Update(ctx, UpdateTaskInput{...}), and .Move(ctx, MoveTaskInput{...}); api_write: ["messages"] enables host.Messages().Send(ctx, taskID, sessionID, text); api_write: ["interactions"] enables the interaction response methods above. A blank sessionID targets the task's primary session. Send queues behind a running session or resumes/starts it when appropriate, returning queued, sent, or started.

Task writes use Kandev's first-party service layer, so normal task events and browser updates occur. Kandev stamps the source as plugin:<id> and reserves the metadata.source key; plugin metadata is stored under that source. .Update writes only title, description, and state: it rejects a workflow step change. Moving a task between workflow steps goes through .Move instead, which routes through the same path the board's own drag-and-drop move uses (validation, WIP admission, task.moved publication, auto-start gates, queue reconciliation), so a plugin-driven move triggers on_enter/on_exit step actions the same way a manual move does. Creating a task can select an existing repository or provide a complete, credential-free remote descriptor only when the plugin owns that repository_providers id. Treat all write calls as user-visible mutations and honor ctx.Done().

Authenticated declared actions

Use a manifest actions entry for a browser action that needs the current Kandev identity and a Kandev resource, not a public webhook. The bundle calls host.api.invokeAction; Kandev authenticates the request, authorizes the declared scope, strips selectors from the untrusted body, and calls the plugin's optional ActionHandler with a VerifiedActionContext.

min_kandev_version: "0.91.1"
actions:
  - key: "pullrequests.link"
    scope: "task"
    access: "authenticated"
    max_body_bytes: 32768

access defaults to authenticated. Set it to admin for instance-wide configuration or credentials that only a Kandev administrator may manage. The host checks this policy before reading the bounded envelope or invoking the plugin, so the plugin does not need to infer roles from actor IDs. An admin action requires min_kandev_version: "0.91.1" or later; validation rejects a missing or older minimum because earlier hosts do not enforce action access.

const result = await host.api.invokeAction(
  "pullrequests.link",
  {
    taskId,
    body: { pullRequestId },
  },
  { signal: controller.signal },
);

The JSON envelope uses camelCase resource selectors: { workspaceId?, taskId?, sessionId?, repositoryId?, body? }. It is not a source of authority. A workspace action requires only workspaceId; a task action requires taskId (an optional matching workspaceId is checked) and may include repositoryId only when that persisted repository is attached to the task. It may include sessionId only when that session belongs to the task. When both are present, Kandev verifies the repository worktree and derives its non-empty head branch; a repository action requires workspaceId and repositoryId. The plugin gets only host-verified actorID, workspaceID, taskID, sessionID, repositoryID, and derived headBranch plus the bounded JSON Body. Unknown actions return 404; bad envelopes and scope-selector combinations return 400; unauthenticated calls return 401; and members calling an admin action receive 403.

The host gives each action 15 seconds and cancels its RPC when the browser abandons the request. Pass the AbortSignal supplied to your UI calls, and in the backend check ctx.Done() before and during provider I/O. An action reply is capped at 1 MiB. A zero response status means 200; explicit statuses from 200 through 599 let the plugin report safe domain failures such as 400, 409, or 429. The response may set only Content-Type, Cache-Control, ETag, or Retry-After; the host rejects invalid statuses, redirects, cookies, arbitrary headers, and unexpected internal error text.

Use pluginsdk.CategorizeActionError or pluginsdk.CategorizeActionErrorWithRetry inside the backend instead of classifying err.Error() text. The stable categories are invalid_argument, unauthenticated, permission_denied, not_found, conflict, rate_limited, unavailable, and upstream; pluginsdk.ActionErrorHTTPStatus projects their shared HTTP status. Preserve wrapped causes for errors.Is/errors.As, but return a sanitized response message. A retry hint belongs in the typed error and the allowed Retry-After header, never in string parsing.

Provider, task, review, and reference registrations

A native bundle can register a manifest-owned repository provider with registry.registerRepositoryProvider(...), children of the task menu's Link submenu with registerTaskAction(...), and review data/panels with registerReviewProvider(...). These registrations are revoked automatically when the plugin disables or uninstalls. Repository and review providers are exclusive by provider id; declare the id in repository_providers before registering it. Provider IDs must already be canonical lowercase identifiers; the manifest and runtime registry reject case variants instead of treating them as separate owners. Provider callbacks receive an AbortSignal and must cancel fetches rather than publishing results after their host surface has gone away. Kandev overwrites RepositoryInspection.providerId with the owning registration ID for both listing and URL inspection, so result data cannot claim another provider's namespace.

matchesURL is an optional, synchronous performance hint, never an ownership decision. Omit it when ownership depends on workspace configuration (especially self-hosted origins). Kandev asks every remaining candidate to run cancellable, workspace-scoped inspectURL; return null for a URL the configured provider does not own. Exactly one structured inspection may succeed. Multiple successes are rejected as ambiguous instead of selecting registration order, while a real inspection failure is surfaced when no provider establishes ownership.

First-use repository task creation

The browser inspectURL callback supports the repository picker. Its result is display data and is not trusted for a native task write. To support a native task that uses a repository not yet saved in the workspace, declare this action:

actions:
  - key: "repositories.inspect"
    scope: "workspace"
    max_body_bytes: 16384

Kandev invokes the active manifest owner from the backend. It supplies a verified workspace context and a body with only the submitted URL:

{"url":"https://code.example.com/owner/repository"}

The preferred response nests the complete descriptor under repository:

{
  "repository": {
    "provider_id": "acme",
    "provider_host": "https://code.example.com",
    "provider_scope": "workspace-a",
    "provider_repository_id": "owner/repository",
    "owner_or_project": "owner",
    "name": "repository",
    "clone_url": "https://code.example.com/owner/repository.git",
    "default_branch": "main"
  }
}

The host also accepts the descriptor fields at the top level for compatibility. Return {"matched":false} when the provider does not own the URL. The host requires a matching provider_id, a valid HTTPS provider origin, a scope of at most 512 bytes, and complete repository identity fields. The clone URL must be HTTPS, contain no credentials, and use the same origin as provider_host. Provider and repository identity fields must not contain NUL bytes. The host also checks any provider scope or repository ID hint that came from the picker.

The action has a 15-second deadline and a 1 MiB response limit. Do not return credentials or provider error details. Invalid output maps to a validation error, {"matched":false} maps to not found, and provider or transport failures map to an unavailable error. After successful inspection, Kandev persists the validated descriptor with the normal native task flow. Existing repository IDs and built-in provider URLs continue to use their existing paths.

A code-host review provider may publish normalized task chrome on each snapshot:

interface ReviewItemSummary {
  providerId: string;
  reviewKey: string;
  title: string;
  url: string;
  connectionScope: string;
  repositoryId: string;
  changeRequestNumber: string | number;
  state: string;
  taskStatus?: {
    number: number | string;
    state: "open" | "merged" | "closed" | "draft";
    pipelineState: "success" | "failure" | "pending" | "neutral";
    checks: readonly {
      id: string;
      label: string;
      state: "success" | "failure" | "pending" | "neutral";
      detail?: string;
      url?: string;
    }[];
    review?: {
      state: "approved" | "changes_requested" | "pending";
      approved: number;
      required?: number;
      requested?: number;
    };
    unresolvedComments?: number;
    loading?: boolean;
    error?: string;
    updatedAt?: number;
  };
}

Kandev automatically renders taskStatus in the same task-topbar button, composer CI chip, desktop hover popover, and mobile drawer used by first-party code hosts. A rendered linked-task row acquires a deduplicated initial provider refresh, so its semantic icon color updates before hover; hover/focus can refresh again. Active topbar/composer status refreshes every 90 seconds. Do not register chat-top-bar/composer lookalikes or run another status poller in the plugin.

If persisted repositories from your provider should populate Kandev's native task branch picker, also declare a workspace-scoped repositories.branches action. Kandev calls it from the backend with body.repository containing the stored, credential-free snake-case descriptor (provider_id, provider_host, provider_repository_id, owner_or_project, name, clone_url, and default_branch). Return {"branches":[{"name":"main","commit":"optional","is_default":true}]}. The active manifest owner is resolved by Kandev; never use browser input to choose the repository or provider for this operation.

reference_sources declares dynamic # composer sources. Implement both SearchEntityReferences and AuthorizeEntityReference: search candidates are display data only. At submission Kandev reconstructs the canonical reference, checks its workspace/provider/kind, and calls the active plugin again with the submission purpose. Return allow only after a current provider-side access check; timeout, error, disabled plugin, or denial fails closed.

For a manifest-owned repository provider, ResolveGitCredential and GetGitCredentialBinding are optional SDK extensions used by the generic Git credential broker. Credentials are transient and must never be logged or persisted. The binding is a non-secret, opaque revision for the exact verified provider/workspace/task/session/repository/host/path scope. Change it whenever credentials rotate or disconnect; Kandev compares it around redemption and revokes provider leases when the plugin becomes inactive, so stale helpers fail closed. Kandev supplies that complete scope for initial host-side cloning too; plugins should reject missing task, session, or repository identity rather than weakening authorization to workspace-only access. The same contract is used for pre-environment origin refresh. Once it succeeds, Kandev's local and worktree preparers use refreshed refs and do not contact the remote again outside the credential seam.

External login (capabilities.auth). An auth-capable plugin can log a visitor in against an external IdP (OIDC/SAML). Handle the IdP callback / SAML ACS in a webhook, validate the token yourself, then set the reserved X-Kandev-Auth-Login response header to a JSON object {"provider","subject","email","display_name"}. Kandev maps it to a user (link-by-email or just-in-time member provisioning), mints the session, and sets the session cookie itself (the host derives the name from the request host: kandev_session on default ports, kandev_session_<port> otherwise, unless auth.cookieName is explicitly configured, in which case that name is used verbatim and must be unique per cookie host); your plugin never handles the raw token, and any Set-Cookie you return is dropped. Requires authentication enabled; emitting the header without capabilities.auth returns 403.

Declare both the initiate webhook and the callback webhook with access: public. Kandev checks the initiate key before it shows the login button. The manifest has no callback field, so your plugin must declare the callback key separately. Kandev logs a warning when a declared initiate webhook is not public.

You MUST only assert an email the IdP has verified as owned by subject. Kandev auto-links that email to (or provisions) an account, so an unverified or user-settable email claim is an account-takeover vector. Kandev refuses to auto-link to an admin account as defense-in-depth, but it cannot tell a verified email from an unverified one; that is on your plugin. See ADR 0050.

Writable data directory. Kandev injects KANDEV_PLUGIN_DATA_DIR into every spawned plugin subprocess: a per-plugin writable directory (~/.kandev/plugins/<id>/data) for anything you'd rather keep on disk than in Host state.

Host-state idempotency example

Declare state, embed the no-op base, and read the Host at handling time because the broker connection may not exist during construction.

capabilities:
  events: ["task.created", "task.state_changed"]
  state: true

import (
  "context"
  "errors"
)

type plugin struct{ pluginsdk.UnimplementedPlugin }

func (p *plugin) OnEvent(ctx context.Context, event *pluginsdk.Event) error {
  if event == nil || event.EventID == "" { return errors.New("event ID is required") }
  host := p.Host()
  if host == nil { return errors.New("plugin host unavailable") }
  value, found, err := host.GetState(ctx, "instance", "", "events")
  if err != nil { return err }
  if !found { value = map[string]any{} }
  processed, _ := value["processed_event_ids"].(map[string]any)
  if processed == nil { processed = map[string]any{} }
  if _, seen := processed[event.EventID]; seen { return nil }
  count := 0.0
  if found { count, _ = value["count"].(float64) }
  processed[event.EventID] = true
  value["processed_event_ids"] = processed
  value["count"] = count + 1
  return host.SetState(ctx, "instance", "", "events", value)
}

The durable EventID claims make retries no-ops. Delivery is sequential per plugin, while Host state itself has no transaction primitive; keep the claim and counter in one state update and bound or prune old claims in a long-lived plugin.

Optional: native UI

A plugin may ship ui.bundle in its manifest: a static browser ES module served verbatim from the extracted package directory. It may be hand-written or generated by your checked-in UI build; package the resulting bundle and never bundle a second React or Radix runtime.

The single entry point: the bundle, once evaluated, calls window.registerKandevPlugin(id, { initialize(registry, host), destroy?() }). Kandev's frontend host imports the bundle on boot (or on runtime enable), then calls initialize(registry, host). On disable/uninstall it calls destroy?.() and bulk-revokes every registration the plugin made.

Registry surface (registry: PluginRegistry, passed to initialize):

interface PluginRegistry {
  // Top-level SPA route, exact-match against window.location path. The host
  // wraps the page in kandev's title bar by default; configure or opt out
  // via options.topbar.
  registerRoute(
    path: string,
    Component: React.ComponentType,
    options?: PluginRouteOptions,
  ): void;
  // Sidebar/main nav entry, rendered by <PluginNavItems/>.
  registerNavItem(item: NavItem): void;
  // Route under /settings/plugins/{id}/..., rendered inside the settings shell.
  registerSettingsRoute(path: string, Component: React.ComponentType): void;
  // Native Settings > Integrations entry and global/workspace settings page.
  registerIntegrationSettings(
    registration: IntegrationSettingsRegistration,
  ): void;
  // Named slot injection. Initial slots: "task-sidebar", "settings-nav",
  // "main-nav-footer", "chat-input-actions", "chat-top-bar", "main-top-bar",
  // "app-status-bar-left", "app-status-bar-right", and "plugin-settings"
  // (see "Named slots" below).
  registerComponent(
    slot: string,
    Component: React.ComponentType<{ slotProps?: unknown }>,
  ): void;
  // WS action handler, bridged into the existing lib/ws dispatch.
  registerWsHandler(action: string, handler: (payload: unknown) => void): void;
  // Bind a handler to a keybinding declared in this plugin's manifest
  // (ui.keybindings[].id). See "Keybindings" below.
  registerKeybinding(id: string, handler: (event: KeyboardEvent) => void): void;
}

type PluginIcon = string | React.ComponentType<{ className?: string }>;

interface NavItem {
  id: string;
  label: string;
  path: string;
  // Curated icon name or plugin-owned component; unknown names render the puzzle glyph.
  icon?: PluginIcon;
  // "main" (default): top-level sidebar entry. "integrations": renders inside
  // the sidebar's Integrations section alongside first-party integration links.
  // Both also render in the phone menu sheet, so plugin pages stay reachable
  // when the desktop sidebar is hidden.
  // "settings" is accepted by the type but not rendered by any sidebar section.
  // Use registerSettingsRoute for plugin administration, or
  // registerIntegrationSettings for service configuration in native Integrations.
  section?: "main" | "settings" | "integrations";
}

interface IntegrationSettingsRegistration {
  id: string;
  label: string;
  description: string;
  icon?: PluginIcon;
  Component: React.ComponentType<{ workspaceId?: string }>;
  // Optional action in the detail section header and integrations index card.
  // The surface identifies the host location.
  action?: React.ComponentType<IntegrationSettingsActionProps>;
}

type IntegrationSettingsActionSurface = "detail" | "index";

interface IntegrationSettingsActionProps {
  workspaceId?: string;
  surface: IntegrationSettingsActionSurface;
}

interface PluginRouteOptions {
  // Kandev-style title bar above the page. Default: enabled with a derived
  // title (from the matching nav item, else the plugin's display name).
  // Pass a PluginPageChrome to configure it, or `false` for a full-bleed
  // page that owns its own chrome (e.g. with host.ui.PageTopbar).
  topbar?: boolean | PluginPageChrome;
}

interface PluginPageChrome {
  title?: string;
  subtitle?: string;
  icon?: PluginIcon;
  backHref?: string; // default "/"
  backLabel?: string; // default "Kandev"
  actions?: React.ComponentType; // rendered on the right side of the topbar
}

Host API (host: PluginHostApi, passed to initialize):

interface PluginHostApi {
  pluginId: string;
  React: typeof import("react"); // shared host React instance; MUST use this, never bundle your own React
  jsx: typeof React.createElement; // convenience alias
  context: {
    getActiveWorkspaceId(): string | undefined;
    subscribeActiveWorkspace(listener): () => void;
    getWorkspaceIds(): readonly string[];
    subscribeWorkspaces(
      listener: (workspaceIds: readonly string[]) => void,
    ): () => void;
    getTaskCreationContext(workspaceId: string): TaskCreationContext | null;
    subscribeTaskCreationContext(workspaceId: string, listener): () => void;
    resolveRepositoryId(identity: {
      workspaceId: string;
      providerId: string;
      providerScope: string;
      providerRepositoryId: string;
    }): string | undefined;
  };
  api: {
    // fetch scoped to /api/plugins/{id}/...; relayed to your webhook handler.
    fetch(path: string, init?: RequestInit): Promise<Response>;
    // Authenticated manifest action. Selectors are verified by Kandev and
    // delivered separately from the untrusted body.
    invokeAction<T>(
      key: string,
      input?: {
        workspaceId?: string;
        taskId?: string;
        sessionId?: string;
        repositoryId?: string;
        body?: unknown;
      },
      options?: { signal?: AbortSignal },
    ): Promise<T>;
    // Backend API origin ("" when the SPA and API share an origin); lets a
    // plugin reach first-party kandev REST endpoints directly.
    baseUrl: string;
  };
  ui: PluginUIApi; // named curated host components; see @kandev/plugin-sdk
  i18n: {
    readonly locale: string;
    t(
      key: string,
      options?: {
        defaultValue?: string;
        count?: number;
        values?: Record<string, string | number>;
      },
    ): string;
    useTranslation(): {
      readonly locale: string;
      t: PluginHostApi["i18n"]["t"];
    };
  };
  theme: "light" | "dark";
  // Soft SPA navigation (history push/replace), same as the app's own router.
  navigate(href: string, options?: { replace?: boolean }): void;
  // Imperatively opens a modal window. See "Modal windows" below.
  openModal(options: PluginModalOptions): PluginModalHandle;
  // Native task change-request link workflow. See "Task link dialogs" below.
  openTaskLinkDialog(options: PluginTaskLinkDialogOptions): PluginModalHandle;
  // Registers one plugin-owned contributor with the native settings save bar.
  // The host prefixes the id with `plugin:<pluginId>:` before coordination.
  useSettingsSaveContributor(contributor: SettingsSaveContributor): void;
  // Publishes one integration registration's live enabled state for one
  // workspace. Persist the source of truth with host.storage and republish it
  // after load.
  setIntegrationEnabled(
    integrationId: string,
    workspaceId: string,
    enabled: boolean,
  ): void;
}

interface SettingsSaveContributor {
  id: string;
  order?: number;
  revision: string | number;
  isDirty: boolean;
  canSave?: boolean;
  invalidReason?: string;
  save(revision: string | number): Promise<void> | void;
  discard(revision?: string | number): Promise<void> | void;
}

interface PluginModalOptions {
  title?: string; // rendered in DialogHeader/DialogTitle; omit for no title
  description?: string; // supporting copy below the title
  content: React.ComponentType; // reuses the slot-component contract
  size?: "sm" | "md" | "lg" | "xl"; // default "md"
  dismissible?: boolean; // overlay click / Escape; default true
  presentation?: "dialog" | "drawer"; // default dialog
}

interface PluginTaskLinkDialogOptions {
  title: string;
  description: string;
  inputLabel: string;
  placeholder?: string;
  emptyError: string;
  failureMessage: string;
  successMessage: string;
  inputTestId?: string;
  errorTestId?: string;
  submitTestId?: string;
  onSubmit(reference: string, signal: AbortSignal): Promise<void>;
}

interface PluginModalHandle {
  close(): void; // no-op if already closed
}

A compatibility-only host.store remains for older bundles, but it is absent from @kandev/plugin-sdk. New plugins must not depend on private AppState records or mutate the SPA store.

A plugin bundle must render with host.React / host.jsx; bundling your own React copy breaks hook identity against the host tree.

host.ui is a curated @kandev/ui subset: Alert, Badge, Button, Card, Checkbox, Dialog, DropdownMenu, Input, Label, Pagination, ScrollArea, Select, Separator, Sheet, Skeleton, Spinner, Switch, Table, Tabs, Textarea, Tooltip (each with their compound sub-parts, e.g. DialogContent, TableRow) plus first-party app UI: Combobox (the app's picker), PageTopbar (the title bar a route gets by default via registerRoute's options.topbar, exposed here for routes that opt out and render their own chrome), and TaskCreateDialog, so a plugin can hand off task creation to kandev's real create-task flow (repo/branch/agent pickers, validation) instead of POSTing directly. Code-host plugins also receive ChangeRequestList, ChangeRequestRow, ChangeRequestDetail, IntegrationListToolbar, IntegrationScopeBar, IntegrationSaveQueryDialog, IntegrationStartTaskMenu, IntegrationIcon, TaskRowIndicator, IntegrationRepositoryFilter, and IntegrationCursorPagination. These are the same provider-neutral dashboard components used by Kandev's GitHub and GitLab pages. Supply normalized data and callbacks instead of cloning their markup: the shared Task preset menu opens TaskCreateDialog directly, while review stays in the plugin's registered task review surface. IntegrationIcon accepts semantic names (pull-request, pull-request-closed, merged, and filter) so code-host plugins use the host's exact glyphs instead of copying SVG paths. Runtime components remain host-owned; do not move or duplicate them in a plugin UI package. See apps/web/lib/plugins/host-api.ts for the exact current list.

Native integration settings also expose IntegrationAuthStatusBanner, IntegrationEnabledControl, SettingsSection, SettingsCard, and WorkspaceScopedSection. The host supplies the shared settings layout and save coordination; the plugin supplies provider fields and persistence.

host.utils.integrationStatusRefreshMs is the host polling interval used by native integration health controls. Use it when a plugin must match that refresh cadence.

A repository provider may implement createChangeRequest. Kandev keeps the native Create PR dialog and Git eligibility rules, pushes the selected checkout through the executor, and only then invokes the provider with the host-verified task and persisted repository plus the session whose checkout was pushed. The provider should forward that sessionId as an authenticated task-action selector; Kandev derives the exact head branch from its session worktree and the plugin uses VerifiedActionContext.HeadBranch. Never send or trust a browser body source branch. Set supportsDraft: false when the provider cannot create drafts. Do not add a second plugin-owned create button or send provider creation through agentctl. Return { url, provider?, output?, linked?, associationError? }. When the remote change request exists but task association failed, return linked: false plus a safe associationError; Kandev warns the user to retry only the Link action and never offers to repeat remote creation. Respect the supplied AbortSignal: cancellation stops host feedback, but it cannot make an already-created remote change request safe to create again. An open registered review participates in the same native action eligibility, so the primary action stops offering Create PR once that change request is linked.

A review provider can implement the workspace association snapshot/subscription/refresh trio plus unlink. Kandev then owns sidebar/Kanban/list PR indicators and the shared desktop/mobile unlink control. unlink removes only the selected task association and must not delete the remote change request. After it resolves, Kandev refreshes both the task review snapshot and the workspace association snapshot. On desktop, hovering or keyboard-focusing an association indicator refreshes the matching task review and renders the same structured pull-request summary used by first-party providers. The host also leases one initial refresh for each rendered linked task, deduplicated with any topbar or panel consumer, so status color does not depend on first opening the popover. Publish ReviewItemSummary.taskStatus to supply state, review, and CI rows; do not add a plugin poller. Mobile exposes the same review data through the native Status and Review surfaces because it has no hover interaction.

Each ReviewTaskAssociation and ReviewItemSummary must include connectionScope, immutable repositoryId, and changeRequestNumber. Kandev matches them only by that complete identity, so a renamed repository remains linked while a new repository reusing the old display path cannot inherit its task or mutation authority. reviewKey is display and lookup data, never an authorization key. The host drops incomplete provider records instead of falling back to a mutable display key.

Registered review panels use host.ui.ChangeRequestDetail, the same detail component consumed by GitHub. Supply provider-neutral identity, state, branches, diff totals, description, reviews, requested reviewers, checks, comments, advertised actions, and refresh/context callbacks. Kandev owns the exact header and section layout, status icons, add-to-context behavior, one scroll container, loading/error states, and native desktop/mobile presentation. Provider-specific review markup is not a supported parity path.

Code-host plugins that must preserve a verified provider descriptor can pass TaskCreateDialog a create-mode transport override:

createTask?: (payload: TaskCreatePayload) => Promise<CreateTaskResponse>;

The callback receives the exact payload built by the native dialog. Route it through your authenticated plugin action and Host Tasks.Create. If omitted, the dialog keeps using Kandev's normal REST task endpoint. The callback is also used for the fresh-branch re-consent retry; edit and session modes ignore it. Send only the native task choices and a per-dialog idempotency identifier. Resolve the provider repository and branch again inside the authenticated plugin action; never accept a browser-supplied repository descriptor as authority. Reuse the identifier for retries of one submission, but generate a new one when the user opens a new launch so one change request can have multiple tasks.

Repository identity is not a display slug. RepositoryInspection.repositoryId must be the provider's immutable repository identifier. Self-managed providers also set providerScope to an opaque, credential-free connection identity that distinguishes instances sharing one authority (for example, two Data Center context roots). Kandev persists this as provider_scope and keys provider rows and managed clone paths by workspace + provider + scope + immutable repository ID. providerHost, owner, name, and clone URL remain routing/display data; reconnecting must not silently reinterpret an older unscoped row.

Modal windows

host.openModal(options) imperatively opens a host-owned Dialog, rendered by a <PluginModalHost/> mounted once inside the authenticated AppShell's theme/tooltip/toast provider tree, isolated behind its own error boundary, and auto-closed if the plugin is disabled or uninstalled while it's open. It's independent of keybindings: call it from a keybinding handler, a nav route, a slot component, or a WS handler. It complements the declarative host.ui.Dialog; reach for host.ui.Dialog when a dialog is embedded in a slot's own render tree, and host.openModal when you need to pop one open imperatively from anywhere in your plugin's code.

const handle = host.openModal({
  title: "Acme settings",
  content: SettingsPanel,
  size: "lg",
});

// later, e.g. after the panel calls back on save:
handle.close();

Task link dialogs

Code-host plugins must use host.openTaskLinkDialog(options) for a task menu's change-request link action. The host renders the same one-field workflow used by GitHub: title and description, inline validation, Cancel/Save footer, submitting state, success toast, and close-on-success. The plugin supplies provider copy and an authenticated submit callback. A child inside the existing Link submenu names only its target, such as Bitbucket Pull Request; do not repeat the parent verb.

host.openTaskLinkDialog({
  title: "Link Acme pull request",
  description: "Use an Acme pull request URL or key for this task.",
  inputLabel: "Pull request",
  placeholder: "workspace/repository#42",
  emptyError: "Enter an Acme pull request URL or key.",
  failureMessage: "Failed to link Acme pull request.",
  successMessage: "Acme pull request linked",
  onSubmit: async (reference, signal) => {
    await host.api.invokeAction(
      "pullrequests.link",
      {
        workspaceId,
        taskId,
        body: { reference },
      },
      { signal },
    );
  },
});

Named slots

registerComponent(slot, Component) injects a component into a host-defined slot. The host renders every plugin's component for that slot (each isolated behind an error boundary), so a slot may hold contributions from several plugins at once. Available slots:

plugin-settings is the one exception to "every plugin's component renders": it is owner-scoped, so the host renders only the component registered by the plugin whose settings page is being viewed. See "Plugin settings page" below.

For a third-party service, use registerIntegrationSettings(...) instead of a settings-nav slot. Kandev adds the native integration index card, workspace settings navigation, and global/workspace routes, then wraps the plugin component in the shared settings section. IDs must be URL-safe, cannot shadow built-in integrations, and stay owned until unload.

Workspace integration state and native save bar

The optional action component and the main integration component both receive the workspaceId from the URL. The action also receives surface, with the value "detail" for the settings header or "index" for the integrations card. Use the workspace value for the workspace that the user is editing. Do not replace it with host.context.getActiveWorkspaceId().

host.setIntegrationEnabled(integrationId, workspaceId, enabled) updates the live Enabled badge for one registration. The host checks the registration owner and keeps the value in memory only. Store the durable value with host.storage, then publish it for every workspace after plugin load:

function publishEnabled(host, integrationId, enabledByWorkspace) {
  for (const workspaceId of host.context.getWorkspaceIds()) {
    host.setIntegrationEnabled(
      integrationId,
      workspaceId,
      enabledByWorkspace.get(workspaceId) === true,
    );
  }
}

const unsubscribe = host.context.subscribeWorkspaces((workspaceIds) => {
  // Refresh durable values for new or removed workspace ids.
});

Use host.useSettingsSaveContributor for plugin drafts that must use the native Save changes bar. Contributor ids are local to the plugin. The host adds a plugin:<pluginId>: prefix before it stores the contributor, so a plugin cannot replace a host contributor with the same local id.

Composer actions

Register chat-input-actions, task-create-input-actions, or new-session-input-actions to add an action to the corresponding composer. Each receives the versioned PluginComposerSlotProps contract described above, including presentation and native insert, focus, and submit capabilities.

A task can hold several sessions, so both the active session and the full sessionIds list are provided. These are kandev session ids; resolving one to an agent/ACP transcript id (for example, to key per-session cost data from a tool like tokscale) is your plugin's job. Do that server-side in your plugin backend via the Host data API (host.Sessions() exposes each session's ACPSessionID), not in the bundle: propagate the ids from the UI to your backend over host.api.fetch(...), and let the backend do the matching.

function makeChatAction(host) {
  const { jsx: h, ui } = host;
  const { Button, Tooltip, TooltipTrigger, TooltipContent } = ui;

  return function ChatAction({ slotProps }) {
    const { taskId } = slotProps ?? {};
    return h(
      Tooltip,
      null,
      h(
        TooltipTrigger,
        { asChild: true },
        h(
          Button,
          {
            type: "button",
            variant: "ghost",
            size: "icon",
            className: "h-7 w-7 cursor-pointer hover:bg-muted/40",
            "aria-label": "Open plugin page",
            onClick: () => host.navigate("/hello-world"),
          },
          /* an icon element built with host.jsx */ myIcon(h),
        ),
      ),
      h(TooltipContent, null, taskId ? `Task: ${taskId}` : "Plugin action"),
    );
  };
}

// inside initialize(registry, host):
registry.registerComponent("chat-input-actions", makeChatAction(host));

Match the first-party toolbar buttons: Button from host.ui with variant="ghost", size="icon", h-7 w-7, cursor-pointer, and a 16px (h-4 w-4) icon. Wrap it in host.ui.Tooltip so it reads like the native mic/attach controls. kandev-plugin-hello/ui/bundle.js ships a working example.

Session top bar

Register a chat-top-bar component to surface at-a-glance status in the session top bar, beside first-party document/editor/debug controls. The host passes the current context as slotProps:

type ChatTopBarSlotProps = {
  taskId: string | null;
  taskTitle?: string;
  workspaceId: string | null;
  activeSessionId: string | null; // session the top bar is bound to
  sessionIds: string[]; // every kandev session id on the task
};

Like chat-input-actions, both the active session and the full sessionIds list are provided (see the note above about resolving kandev session ids to ACP transcript ids server-side). The top bar is a compact horizontal strip, so keep contributions to small badges or h-7 buttons that match the native metric chips.

// inside initialize(registry, host):
registry.registerComponent("chat-top-bar", makeTopBarStatus(host));

Default app top bar

Register a main-top-bar component to add status or a small action to the default app top bar, the strip across the Home, Kanban, and Tasks views, beside the CPU/DB metrics and the view/display controls. This is the app-wide, task-agnostic counterpart to chat-top-bar: use it for something that isn't tied to one session (a workspace-level indicator, a global quick action). The host passes:

type MainTopBarSlotProps = {
  workspaceId: string | null; // workspace the top bar is showing, null on global home
  workspaceLabel?: string; // human-readable workspace name, when known
  currentPage: "kanban" | "tasks";
  presentation: "desktop" | "mobile";
};

Because the bar is not scoped to a task, no task/session ids are provided. Like chat-top-bar it is a compact horizontal strip, so keep contributions to small badges or icon buttons. On a phone, presentation is "mobile"; the contribution joins the horizontally scrollable middle strip between the fixed Kandev link and menu button. Use host.ui.Button for documented icon actions. The host normalizes those buttons to a 32px box and their SVG icons to 16px. Do not add a second horizontal scroll container. Desktop contributions keep their existing sizing.

// inside initialize(registry, host):
registry.registerComponent("main-top-bar", makeAppBarStatus(host));

Plugin settings page

Register a plugin-settings component to render your own UI inline on your plugin's administration page (Settings > Plugins > <plugin>), at the top above the schema-driven settings form. Use it for package/runtime health or custom controls alongside that form. Service credentials, provider health, defaults, and saved watches belong in registerIntegrationSettings(...). The host passes:

type PluginSettingsSlotProps = {
  pluginId: string; // the plugin whose settings page is being viewed (always yours)
  status: "registered" | "active" | "error" | "disabled" | "uninstalled";
};

Unlike the other slots, plugin-settings is owner-scoped: the host renders only the component registered by the plugin currently being viewed, so your card appears on your own settings page and never on another plugin's; you do not need to gate on slotProps.pluginId yourself. The host provides no wrapper card, so your component owns its own card and can render null when it has nothing to show.

// inside initialize(registry, host):
registry.registerComponent("plugin-settings", makeSettingsStatus(host));

Global Status bar

Register app-status-bar-left or app-status-bar-right for app-wide, compact status UI. Kandev mounts exactly one presentation: a 24 px bar on tablet and desktop, or an in-flow Status drawer section on phone. Keep bar content small; render a touch-usable row when presentation is "mobile-drawer".

function StatusContribution({ slotProps }) {
  const { placement, presentation, activeTaskId } = slotProps ?? {};
  return host.jsx(
    "span",
    {
      className:
        presentation === "bar"
          ? "truncate text-xs"
          : "block min-h-11 px-3 py-2",
    },
    `${placement}: ${activeTaskId ?? "no active task"}`,
  );
}

registry.registerComponent("app-status-bar-left", StatusContribution);
registry.registerComponent("app-status-bar-right", StatusContribution);

Each contribution receives this exact context:

type AppStatusBarSlotProps = {
  placement: "left" | "right";
  presentation: "bar" | "mobile-drawer";
  density: "full" | "compact";
  pathname: string;
  activeWorkspaceId: string | null;
  activeTaskId: string | null;
  activeSessionId: string | null;
};

The IDs are opaque context hints. Use a typed host.context read or a host-verified plugin action when the public contract exposes the needed record; request a context API extension rather than reading private store slices. Each component registration is one opaque item: Kandev does not inspect or separately reorder its children. The slot chooses the default side. A user can Cmd-drag (macOS) or Ctrl-drag (other desktop platforms) with a mouse across the full bar, and Kandev preserves that backend-owned order across reloads, restarts, and plugin disable/enable. Phone lists the saved left sequence followed by the saved right sequence and does not offer drag ordering. There is no keyboard-arrow, touch, or plugin-priority ordering API. Enable, disable, and uninstall update the live surface without a reload, and each contribution has its own error boundary. A full-bleed route (topbar: false) owns its own chrome; mount the host Status trigger there if that route should expose Status.

3. Task panel with task-scoped Host state

There is now a real registerTaskPanel and per-user host.storage; prefer them over the old task-sidebar-plus-webhook workaround.

capabilities:
  user_state: true

function useNoteValue(taskId, panelId) {
  const [value, setValue] = host.React.useState("");
  const [loadedTaskId, setLoadedTaskId] = host.React.useState(null);
  const [readError, setReadError] = host.React.useState(false);
  const updatedAtRef = host.React.useRef(undefined);
  const dirtyRef = host.React.useRef(false);
  // Holds cancellation/generation state outside the effect so `refresh` is a
  // stable function the conflict-refetch below can also call, instead of
  // duplicating the read-and-commit logic without its guards.
  const guardRef = host.React.useRef({ cancelled: false, generation: 0 });

  const refresh = host.React.useCallback(
    (options = {}) => {
      const preserveValue = options.preserveValue ?? dirtyRef.current;
      const guard = guardRef.current;
      const generation = ++guard.generation;
      return host.storage.get("task", taskId, "note").then(
        (entry) => {
          // Ignore a response that resolves after taskId changed, the panel
          // unmounted, or a newer refresh started; otherwise a stale read
          // (the previous task's note, or one of two overlapping reads that
          // resolved out of order) can land in the current field.
          if (guard.cancelled || generation !== guard.generation) return;
          if (!preserveValue && !dirtyRef.current)
            setValue(entry ? entry.value : "");
          updatedAtRef.current = entry ? entry.updatedAt : undefined;
          setLoadedTaskId(taskId);
          setReadError(false);
          return true;
        },
        () => {
          // Do not mark the task loaded after a rejected read. Rendering an
          // empty editor here would allow its first save to omit
          // ifUnmodifiedSince and overwrite an existing note. Keep the panel
          // in a retry state until an authoritative read succeeds.
          if (guard.cancelled || generation !== guard.generation) return false;
          setReadError(true);
          return false;
        },
      );
    },
    [taskId],
  );

  host.React.useEffect(() => {
    const guard = guardRef.current;
    guard.cancelled = false;
    // Clear the previous task's value/timestamp synchronously; otherwise it
    // stays on screen (and could be sent as ifUnmodifiedSince under the new
    // taskId) until this effect's first refresh() resolves.
    setValue("");
    updatedAtRef.current = undefined;
    dirtyRef.current = false;
    setLoadedTaskId(null);
    setReadError(false);
    refresh();
    // Scope echo suppression to this panel instance rather than the shared
    // per-tab default writer id; otherwise a second surface editing the
    // same note (a kanban shortcut, another panel) looks like this panel's
    // own echo and its write never arrives here.
    const unsubscribe = host.storage.subscribe(
      { scope: "task", scopeId: taskId, key: "note", writerId: panelId },
      refresh,
    );
    return () => {
      guard.cancelled = true;
      unsubscribe();
    };
  }, [taskId, panelId, refresh]);
  return {
    value,
    setValue,
    updatedAtRef,
    dirtyRef,
    loaded: loadedTaskId === taskId,
    readError,
    refresh,
  };
}

function NotesPanel({ taskId, panelId }) {
  const {
    value,
    setValue,
    updatedAtRef,
    dirtyRef,
    loaded,
    readError,
    refresh,
  } = useNoteValue(taskId, panelId);
  const [conflict, setConflict] = host.React.useState(false);
  const [writeError, setWriteError] = host.React.useState(false);
  const pendingValueRef = host.React.useRef(undefined);
  const writeTimerRef = host.React.useRef(undefined);
  const writeInFlightRef = host.React.useRef(false);
  const writeBlockedRef = host.React.useRef(false);
  const writeGenerationRef = host.React.useRef(0);

  const flushWrite = host.React.useCallback(() => {
    if (
      writeBlockedRef.current ||
      writeInFlightRef.current ||
      pendingValueRef.current === undefined
    ) {
      return;
    }
    const generation = writeGenerationRef.current;
    const next = pendingValueRef.current;
    pendingValueRef.current = undefined;
    writeInFlightRef.current = true;
    host.storage
      .set("task", taskId, "note", next, {
        writerId: panelId,
        ifUnmodifiedSince: updatedAtRef.current,
      })
      .then((result) => {
        if (writeGenerationRef.current !== generation) return;
        updatedAtRef.current = result.updatedAt;
        dirtyRef.current = pendingValueRef.current !== undefined;
        setConflict(false);
        setWriteError(false);
      })
      .catch((error) => {
        if (writeGenerationRef.current !== generation) return;
        // Stop the queue on a conflict. Refresh only the authoritative
        // timestamp and preserve the local value so the user can choose
        // whether to retry their edit; never replace dirty text silently.
        pendingValueRef.current = pendingValueRef.current ?? next;
        writeBlockedRef.current = true;
        if (error.name === "PluginStorageConflictError") {
          setConflict(true);
          return refresh({ preserveValue: true });
        }
        setWriteError(true);
      })
      .finally(() => {
        if (writeGenerationRef.current !== generation) return;
        writeInFlightRef.current = false;
        if (!writeBlockedRef.current && pendingValueRef.current !== undefined) {
          writeTimerRef.current = setTimeout(() => {
            if (writeGenerationRef.current !== generation) return;
            writeTimerRef.current = undefined;
            flushWrite();
          }, 150);
        }
      });
  }, [dirtyRef, panelId, refresh, taskId, updatedAtRef]);

  const scheduleWrite = host.React.useCallback(() => {
    if (writeBlockedRef.current || writeTimerRef.current !== undefined) return;
    const generation = writeGenerationRef.current;
    writeTimerRef.current = setTimeout(() => {
      if (writeGenerationRef.current !== generation) return;
      writeTimerRef.current = undefined;
      flushWrite();
    }, 150);
  }, [flushWrite]);

  const retryWrite = host.React.useCallback(async () => {
    if (!(await refresh({ preserveValue: true }))) return;
    writeBlockedRef.current = false;
    setConflict(false);
    setWriteError(false);
    scheduleWrite();
  }, [refresh, scheduleWrite]);

  host.React.useEffect(() => {
    const generation = ++writeGenerationRef.current;
    pendingValueRef.current = undefined;
    writeInFlightRef.current = false;
    writeBlockedRef.current = false;
    setConflict(false);
    setWriteError(false);
    return () => {
      if (writeGenerationRef.current === generation)
        writeGenerationRef.current += 1;
      pendingValueRef.current = undefined;
      writeInFlightRef.current = false;
      writeBlockedRef.current = false;
      if (writeTimerRef.current !== undefined)
        clearTimeout(writeTimerRef.current);
      writeTimerRef.current = undefined;
    };
  }, [taskId, panelId]);

  if (readError) {
    return host.jsx(
      "button",
      { type: "button", onClick: refresh },
      "Could not load this note. Retry",
    );
  }
  if (!loaded) return host.jsx("div", null, "Loading...");
  const editor = host.jsx(host.ui.RichTextEditor, {
    taskId,
    value,
    onChange: (next) => {
      setValue(next);
      dirtyRef.current = true;
      pendingValueRef.current = next;
      scheduleWrite();
    },
  });
  const status = conflict
    ? host.jsx(
        "div",
        null,
        "This note changed elsewhere. Your edit is preserved.",
        host.jsx(
          "button",
          { type: "button", onClick: retryWrite },
          "Retry my edit",
        ),
      )
    : writeError
      ? host.jsx(
          "div",
          null,
          "Could not save this note.",
          host.jsx("button", { type: "button", onClick: retryWrite }, "Retry"),
        )
      : null;
  return host.jsx("div", null, editor, status);
}

registry.registerTaskPanel({
  id: "notes",
  title: "Notes",
  icon: "book",
  Component: NotesPanel,
  mobileEnabled: true,
});

On a phone, all mobileEnabled panels appear under one Panels bottom-nav action. The picker uses a touch-sized, internally scrolling sheet with each panel's icon and title; selecting a row dismisses the picker and focuses that panel as the single full-height mobile surface. The component receives presentation: "mobile"; desktop dockview receives presentation: "desktop". The same registration and panel identity drive both viewports, so a panel remains selected through a slow or failed reload and is closed only after a ready generation omits it or the plugin is explicitly disabled/uninstalled.

writerId is appended to the host's own per-tab id, not a full replacement; a static value like panelId is the same across every tab that has that panel open, so two different tabs subscribing with the same raw panelId would otherwise suppress each other's real, cross-tab updates as if they were local echoes. Pass ifUnmodifiedSince (the updatedAt from the last get) to set and handle the resulting 409 by refetching, rather than silently discarding a concurrent edit. host.storage.list returns every entry under a (scope, scopeId) pair with no pagination; fine for a handful of keys per task, not for an unbounded per-item collection.

4. Webhook receiver

Declare the route, validate the method and provider signature inside the backend, and return a bounded status/body. Public webhooks are capped at 4 MiB. For plugin-UI operations, declare access: authenticated; those routes may raise max_body_bytes to 16 MiB. Kandev verifies the current user but strips its session cookie and PAT before relaying the remaining headers.

On an instance with authentication enabled, a caller identified by the session cookie must additionally look same-origin, because that cookie is ambient and a page on another site could otherwise make the browser send it. The host accepts the request in exactly two cases:

• it carries an accepted Origin; or
• it carries no Origin and Sec-Fetch-Site is same-origin or none.

Everything else is rejected, including Sec-Fetch-Site of cross-site or same-site and a request carrying neither header. Browsers omit Origin on same-origin GET and HEAD requests, so the second rule is what lets a panel poll its own webhook with GET. In practice host.api.fetch from an active ui.bundle satisfies it with no work on your part, whatever method you use.

Callers identified by a PAT are not subject to this check at all, because a PAT is not ambient. That is the supported way to call an authenticated webhook from outside a browser (a script, a CLI, your own backend); a replayed session cookie carries no origin signal and is refused.

webhooks:
  - key: "provider-events"
    description: "Provider event callback"
    method: "POST" # informational; enforce it in HandleWebhook

func (p *plugin) HandleWebhook(ctx context.Context, req *pluginsdk.WebhookRequest) (*pluginsdk.WebhookResponse, error) {
  if req.WebhookKey != "provider-events" || req.Method != http.MethodPost {
    return &pluginsdk.WebhookResponse{Status: http.StatusNotFound}, nil
  }
  if !validProviderSignature(req.Headers, req.Body) {
    return &pluginsdk.WebhookResponse{Status: http.StatusUnauthorized}, nil
  }
  // Decode, deduplicate, and enqueue the event before returning.
  return &pluginsdk.WebhookResponse{Status: http.StatusAccepted}, nil
}

5. Event subscriber

Subscribe to exact subjects or one-segment wildcards and make processing idempotent by EventID.

capabilities:
  events: ["task.created", "task.state_changed"]

func (p *plugin) OnEvent(ctx context.Context, event *pluginsdk.Event) error {
  // Apply the durable EventID claim pattern from the Host-state recipe before
  // performing side effects.
  if event.EventType == "task.created" { return p.handleTask(ctx, event.Payload) }
  return nil
}

For critical workflows, periodically reconcile from host.Tasks() or another Host reader because event queues are bounded and delivery is best-effort.

6. Task contributions

registerTaskMenuAction adds an item to native task menus. Group "edit" is card-only and nests inside the kanban card's Edit submenu. Group "primary" renders as a flat top-level item on cards and desktop/mobile task-row menus. task-card-indicators (see the named slots table) is the matching read-only surface, rendered beside the PR status icon on every card. task-card-tags is a sibling read-only surface with the same slotProps shape, mounted in its own row instead of that cramped title-row spot; reach for it when a contribution (for example, a row of tag chips) needs its own width. visible(context) and run(context) receive the actual presentation. The value is "desktop" or "mobile" for the current native task menu.

task-row-metadata is the plugin-agnostic compact counterpart for the sidebar task tree and /tasks list. It receives { taskId, workspaceId, workflowStepId, surface: "sidebar" | "task-list" }. Use it for read-only metadata such as labels, ownership, provider state, or tags. An empty slot adds no wrapper or spacing.

registry.registerTaskMenuAction({
  id: "enhance-notes",
  label: "Enhance notes",
  group: "edit",
  visible: (context) => Boolean(context.taskId),
  run: async (context) => {
    await host.storage.set("task", context.taskId, "note", "...");
  },
});

With no plugin action registered, the card's Edit item stays flat; once any plugin registers one for group "edit", it becomes Edit > Edit task followed by each visible action. A run that throws or rejects is caught and logged, not left to crash the card; the menu closes either way. Group "primary" actions render and behave the same way as their own top-level row, including in desktop and phone task-row menus. Do not patch first-party task components directly.

registerTaskFilter adds a client-side, multi-select filter section to the kanban board's display dropdown, next to the built-in Workflow and Repository sections. The plugin supplies its own options (including any "untagged"-style sentinel; the host does not special-case option values) and a matches predicate; filtering runs entirely against tasks already loaded in the board's in-memory state, with no backend query or persistence; selections reset on reload.

registry.registerTaskFilter({
  id: "tags",
  label: "Tags",
  getOptions: () => [
    { value: "bug", label: "Bug", color: "#ef4444" },
    { value: "untagged", label: "Untagged" },
  ],
  matches: (context, selected) => taskHasAnyTag(context.taskId, selected),
});

An empty selection is implicit "All" for that section: matches is only called once at least one option is selected, and a matches that throws is caught, logged, and treated as non-matching for that task.

Use registerTaskListFacet when a plugin owns values that users should sort or group on in the /tasks list. Values are synchronous and apply only to the currently loaded page. A facet is removed automatically when its plugin unloads; optional subscriptions let it refresh the page. Return each value at most once for a task. Keep the same label and color for a value across all tasks. Facet sorting uses the first value label after a case-insensitive alphabetical comparison. Tasks with multiple values appear in every matching group. A task without a value is shown in the host's Ungrouped section. A child whose parent does not match a group is rendered at that group's root.

registry.registerTaskListFacet({
  id: "tags",
  label: "Tag",
  getValues: ({ taskId, workspaceId }) => taskTags(taskId, workspaceId),
  subscribe: (listener) => tagStore.subscribe(listener),
});

Build, package, install, and test

Plugin repository

From the plugin repository created from the official template:

go test ./...
go vet ./...
make package-host       # local platform, fastest loop
make package            # all platforms declared by the template

The template's package target stages manifest.yaml, server/, ui/, and assets, then runs the monorepo plugin-pack command. If using a custom Makefile, the equivalent is:

rm -rf .build/stage
mkdir -p .build/stage/server
cp manifest.yaml .build/stage/manifest.yaml
if [ -d ui ]; then cp -R ui .build/stage/ui; fi
if [ -d assets ]; then cp -R assets .build/stage/assets; fi
go build -o .build/stage/server/plugin-$(go env GOOS)-$(go env GOARCH) ./server
go run github.com/kandev/kandev/cmd/plugin-pack \
  -dir .build/stage \
  -out acme-dashboard-0.1.0.tar.gz \
  -platform-only

plugin-pack requires manifest.yaml, rejects pre-supplied checksum files, and generates checksums.txt. It is a packager, not an exhaustive semantic or JavaScript validator: it does not execute the plugin or prove every referenced UI asset is valid.

In-tree fixture validation

The monorepo provides a maintained package smoke path without a production instance:

make -C apps/backend e2e-plugin-package
cd apps/backend
go test ./cmd/plugin-pack ./cmd/plugin-fixture ./internal/plugins/manifest \
  ./internal/plugins/pkgtar ./pkg/pluginsdk

The fixture build proves the current SDK/package shape and produces a host-platform archive. pkgtar.Install is the install-time authority for manifest validity, safe archive paths, checksums, managed runtime, and the host executable. It also extracts the package; it does not run the plugin or perform a full browser/module build.

Disposable-instance smoke test

Install the archive through Settings > Plugins or the local API:

curl -F "package=@acme-dashboard-0.1.0.tar.gz" \
  http://localhost:38429/api/plugins/install

Then enable it, open each registered route, exercise every declared webhook or event, verify denied capabilities fail as expected, and disable/re-enable to confirm destroy and state preservation. Uninstall only in a disposable instance; it removes the plugin package and KANDEV_PLUGIN_DATA_DIR.

Reinstalling the same id/version is rejected. Bump version or uninstall before repackaging.

Common mistakes

• Missing the leading slash: ui.bundle and ui.styles must be root-relative (/ui/bundle.js, /ui/plugin.css), not ui/bundle.js.
• Forgetting capabilities: every Host state, secret, data-reader, write, or utility-agent call fails with PermissionDenied unless its manifest capability is present.
• Confusing plugin_state with host.storage: Host state is backend, plugin-scoped JSON with no per-user identity; host.storage is per-user.
• Reusing a raw surface id as writerId: a static id like panelId is the same across every tab that has that surface open. Passed as-is to host.storage's writerId, it makes two different tabs look like the same writer and suppresses real cross-tab updates as if they were local echoes; the host already appends it to a per-tab id, so pass the surface id, not a fabricated combined string.
• Writing outside KANDEV_PLUGIN_DATA_DIR: arbitrary files belong below the injected per-plugin directory; do not write beside the Kandev database or into another plugin's directory.
• Leaving stale frontend registrations: use destroy, unsubscribe store/WS listeners, clear timers, and rely on host bulk revocation after disable or uninstall.
• Importing direct DB/internal packages: use apps/backend/pkg/pluginsdk and typed Host methods. Direct database access is outside the plugin contract.
• Trusting webhook metadata: webhooks[].method is informational. Public routes are not authenticated by Kandev, so validate method, signature, timestamp, replay protection, and body before side effects.
• Authenticated webhook access: a valid Kandev session or PAT, plus a same-origin request for the session case, is all the host checks. Any signed-in user reaches an authenticated webhook, so enforce your own per-user or per-role rules when the endpoint needs them. It is not an authorization boundary, and it is not a CSRF boundary for your own state either: the host proves the request came from its own origin, not that the user meant to trigger whatever your handler does.
• Bundling React: use host.React, host.jsx, and host.ui; a second React or Radix copy breaks shared contexts and portals.
• Shipping the wrong binary name: every declared executable must be under server/, match its - key, and include .exe on Windows.

Related: Plugins, Plugin manifest reference, Plugin marketplace, and Extending Kandev.