Tianyi Cui
436305b1c2
Codex's second pass caught that the prior doc fix swapped one wrong primitive for another: framing teardown as cancel()+whenIdle() (or awaiting agent.whenIdle() on disposal) is still wrong. whenIdle() only OBSERVES quiescence; cancel() only stops queued/in-flight work. Neither unregisters the agent or detaches the session. Real teardown is AgentHandle.dispose(), whose disposer does `stop(); await agent.done` — stop the loop, await its exit, and unregister (packages/core/agent-loop/src/index.ts:271). Copying the old framing would reintroduce the orphaned-agent/session leak the AgentHandle seam exists to prevent. - docs/architecture.md: whenIdle() is a non-owner quiescence-observation hook, explicitly NOT teardown; teardown is `await AgentHandle.dispose()`. - docs/cookbook/extension-cookbook.md (prose + the ts comment): tear agents down via AgentHandle.dispose(), not agent.whenIdle(). - docs/rfc/proposed/feature/2026-06-14-acp-agent-client-protocol.md: the lifecycle/disposal paragraph routes teardown through the handle's dispose().
87 lines
4.7 KiB
Markdown
87 lines
4.7 KiB
Markdown
# Cookbook: extension plugin shapes
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The three plugin shapes you write against the harness extension surface, as illustrative snippets (elided imports and helper stubs — not copy-paste-complete). For the full step-by-step guides see [adding a package](./adding-a-package.md), [adding a tool](./adding-a-tool.md), and [adding an LLM adapter](./adding-an-llm-adapter.md); for the seams these hook into see [docs/architecture.md](../architecture.md).
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## A tool plugin
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A tool registers on `ctx.tools`. The annotated `defineTool` example (typed `execute` args, result shaping, the `run_in_background` pattern) lives in [adding-a-tool.md](./adding-a-tool.md) — that guide is the source of truth for the tool shape. Raw JSON-Schema `ToolDefinition`s are also accepted by `ctx.tools.register()` directly (that is how MCP-sourced tools arrive); `defineTool` is the typed sugar for first-party tools.
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## A hook plugin (permission gate)
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A hook wraps the `tools/execute` waterfall to veto or rewrite a call — the seam where sandbox, permission, and plan-mode plugins live.
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```ts
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import type { Context } from 'cordis'
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import type { ToolExecution } from '@deepseek-ai/dsh-tools'
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declare function isAllowed(exec: ToolExecution): Promise<boolean>
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export const name = 'permission-gate'
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export function apply(ctx: Context) {
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ctx.on('tools/execute', async (exec, next) => {
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if (!(await isAllowed(exec))) {
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return {
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callId: exec.callId,
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content: [{ type: 'text', text: 'Denied by policy.' }],
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isError: true,
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}
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}
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return next()
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})
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}
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```
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## A UI plugin
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A UI plugin consumes `agent/stream-chunk` and session events for rendering, and drives input back in via `agent.send()` / `agent.steer()`.
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```ts
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import type { Context } from 'cordis'
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import { AgentId } from '@deepseek-ai/dsh-agent'
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declare function render(text: string): void
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declare function onUserInput(handler: (text: string) => void): void
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export const name = 'my-ui'
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export const inject = ['agents']
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export function apply(ctx: Context) {
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ctx.on('agent/stream-chunk', (agent, turn, step, chunk) => {
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if (chunk.type === 'text-delta') render(chunk.text)
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})
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onUserInput(text => ctx.agents.get(AgentId('main'))?.send([{ type: 'text', text }]))
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}
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```
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## A client-driver plugin (external protocol bridge)
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A *client driver* is a UI plugin whose "user" is another program speaking a wire protocol rather than a human at a terminal. It owns the process's stdio (so it must run with **no stdout logger** — every non-protocol byte corrupts the stream), creates/resumes agents on demand through the `dsh-agent` factory seam, translates harness events (`session/event`, `agent/*`) into outbound protocol messages, and translates inbound requests back into `agent.send()` / `agent.cancel()`. Two harness-specific contracts make it correct: resolve each request exactly once off a settle signal (the turn can end without its `agent/turn-end` event firing — fall back through the logged `turn/end` record), and tear each agent down through its `AgentHandle.dispose()` (which stops the loop, `await`s its exit, and unregisters), not just `cancel()` — disposal must *reach* quiescence, not merely request it.
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`packages/ui/acp` is the worked example: it bridges the agent to the Agent Client Protocol (JSON-RPC over stdio) so Zed and other ACP editors can drive it. See its README for the full method surface and the deferred-permission-gate note.
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```ts
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import type { Context } from 'cordis'
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export const name = 'my-protocol-bridge'
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export const inject = ['agents', 'sessions', 'sessionPersistence']
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export function apply(ctx: Context) {
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// Stream every logged assistant text/reasoning delta out to the client.
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ctx.on('session/event', (_session, event) => {
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if (event.type === 'assistant/chunk') {
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const chunk = event.data.chunk
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if (chunk.type === 'text-delta') {
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// sendToClient({ kind: 'message_chunk', text: chunk.text })
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}
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}
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})
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// Inbound "prompt": create/resume an agent and feed it; settle on turn end.
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// Teardown reaches quiescence via AgentHandle.dispose() (stop + await exit).
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}
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```
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## Runnable wirings
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Three complete examples load their plugin trees from `cordis.yml` with HMR: [`examples/echo-agent`](../../examples/echo-agent) (mock model + echo tool — the all-mock skeleton check, `pnpm run demo:echo`), [`examples/coding-agent`](../../examples/coding-agent) (DeepSeek V4 + the bash tool suite — the real thing, `pnpm run demo:coding`), and [`examples/acp-agent`](../../examples/acp-agent) (the same coding agent exposed as an ACP server over JSON-RPC stdio — the client-driver shape, `pnpm run demo:acp`). The two real demos share their provider/tool core via [`examples/base.yml`](../../examples/base.yml).
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