Tianyi Cui
c182543dd5
Per a design revision, the per-scenario snapshot fixture becomes EXACTLY the persisted session JSONL (<scenario>/session.jsonl) rather than a hand-authored llm.json. The log already holds all LLM behavior (assistant/chunk carries every StreamChunk) AND all harness behavior (tool/call, tool/result, turn/*, usage), so one artifact drives replay and doubles as a behavioral golden. llm-replay becomes replay-only (the record-tee is removed; recording is now "run the real agent once and harvest the .jsonl", done by the harness in a later commit). deriveReplayScript(events) groups assistant/chunk by (turn,step) in log order — exact because the loop makes one ctx.llm.stream() call per step and tags each chunk with the current (turn,step). The two failure modes the log can't express (a thrown stream — no terminal finish; cancel/hang — timing) use an optional replay.override.json sidecar. Hardens against a Codex review finding: a derived group is only valid if it ends in a `finish` chunk. A group without one is the fingerprint of a thrown stream() and is NOT silently replayed as a clean stop — deriveReplayScript throws, naming the (turn,step), so a missing sidecar override fails loud. Updates the unit tests (parse/derive/load helpers, sidecar override, finish- terminated grouping, HMR), the example README, and the RFC prose to the JSONL format. Two goldens (stdout transcript + re-persisted JSONL) and the harness wiring land in the next commit.
40 lines
2.8 KiB
Markdown
40 lines
2.8 KiB
Markdown
# acp-agent example
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The DeepSeek Harness coding agent exposed as an **Agent Client Protocol (ACP)** server over JSON-RPC stdio — drive it from Zed or any other ACP client.
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```sh
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pnpm run demo:acp # needs DEEPSEEK_API_KEY (repo-root .env or env)
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```
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This boots `@deepseek-ai/dsh-acp` over the shared provider/tool core (`../base.yml`), with `agent-loop` configured with **no pre-created agents** (ACP `session/new` creates them on demand) and JSONL session persistence (so `session/load` works).
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## stdout is the protocol
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This example loads **no stdout logger** — `stdout` carries the JSON-RPC frames, and any other write corrupts them. Do not add `@cordisjs/plugin-logger-console` or a stdio UI here. Use a stderr exporter if you need logs.
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## Zed configuration
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Add to your Zed `settings.json` under `agent_servers`:
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```json
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{
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"agent_servers": {
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"DeepSeek Harness": {
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"command": "pnpm",
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"args": ["run", "demo:acp"],
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"env": { "DEEPSEEK_API_KEY": "sk-…" }
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}
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}
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}
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```
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The editor sets each session's `cwd` to the project it opens; the agent's bash tools run there (see the per-session `cwd` note in `packages/acp`), so the server does not need to be launched in the workspace.
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## Snapshot tests (record-once / replay-deterministic)
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This example is the home of the harness's **snapshot tests** — they boot this server as a real subprocess, drive it with a deterministic input script, and diff its normalized output against committed golden files. The model is made deterministic by `src/llm-replay.ts`, a function/namespace plugin that installs an `llm/stream` waterfall listener and short-circuits it, serving model streams reconstructed from a recorded **session JSONL** fixture (`<scenario>/session.jsonl`) — so replay needs no API key. The fixture IS the persisted session log: its `assistant/chunk` events carry every `StreamChunk`, so grouping them by `(turn, step)` reconstructs each `stream()` call (one model call per loop step). Recording is therefore "run the real agent once and harvest the `.jsonl`". The two failure modes not expressible as logged chunks — a pure throw before any chunk, and cancel/hang — use an optional `<scenario>/replay.override.json` sidecar (a `ReplayEntry[]` that replaces the derived script). See [docs/rfc/implemented/2026-06-19-acp-snapshot-tests.md](../../docs/rfc/implemented/2026-06-19-acp-snapshot-tests.md) for the full design.
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## MVP limitations
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The bridge supports N concurrent sessions per connection, each in its own workspace `cwd` (RFC 011). Remaining limits: text-only prompts, `additionalDirectories` rejected (a session operates in its single `cwd`), and the tool-permission gate is deferred (`TODO(rfc010-permission-gate)` — tools run with the executor's full authority). See `packages/acp/README.md` for the full contract.
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