b0422f2a50
Codex review of the trace-event fold found two merge-blockers. Blocker #1 — format version. Folding usage onto assistant/message and removing the standalone usage/error events changed the persisted SessionEventMap shape, which per the AGENTS.md "bump the version and reject — don't migrate" policy requires a backend to reject any non-current log. Centralize the version in an exported SESSION_FORMAT_VERSION constant (dsh-session), read by both write sites (Session constructor default, SessionStore.prepare header) and the coordinator's load-time assertVersion check. The constant is pinned at 0: while unreleased the on-disk format is unstable/pre-release, so breaking shape churn is absorbed at v0 (no monotonic bump until the first tagged release) and any non-0 log is rejected on load — no migration. Update every test/fixture/doc that stamps a currently-written header to the constant, bump the ACP snapshot fixture + golden headers to v0, and keep the version-rejection test meaningful by switching its bad value to a clearly non-current 99. AGENTS.md documents both the monotonic (SQLite SCHEMA_VERSION) and pinned-0 (session log) pre-release stances. Blocker #2 — restore the late turn-end warn. failTurn now sets the error reason only while the turn is still open; once turn/end is appended (a throwing agent/turn-end listener after closeTurn) the reason can no longer reach the durable log, so the late throw is logged via ctx.logger.warn instead of vanishing into a futile post-close assignment. A regression test asserts the warn fires. Also guard the normal-step assistant/message append with the same content-or-usage condition as the max-tokens branch (a content-less, usage-less step records no trace-only row), with a covering test.
acp-agent example
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.
pnpm run demo:acp # needs DEEPSEEK_API_KEY (repo-root .env or env)
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).
stdout is the protocol
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.
Zed configuration
Add to your Zed settings.json under agent_servers:
{
"agent_servers": {
"DeepSeek Harness": {
"command": "pnpm",
"args": ["--dir", "/path/to/deepseek-harness", "run", "demo:acp"],
"env": { "DEEPSEEK_API_KEY": "sk-…" }
}
}
}
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/ui/acp), so launch the server from the harness repo with pnpm --dir … and let ACP carry the workspace path per session.
Snapshot tests (record-once / replay-deterministic)
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 @deepseek-ai/dsh-llm-replay, 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). A scenario that needs the agent to operate on existing files ships an optional <scenario>/workspace/ directory — the harness copies its contents into the temp cwd before the run (see workspace-edit). See docs/rfc/implemented/2026-06-19-acp-snapshot-tests.md for the full design.
MVP limitations
The bridge supports N concurrent sessions per connection, each in its own workspace cwd (RFC 011). Remaining limits: prompts support ACP's baseline text and resource_link blocks only, additionalDirectories and mcpServers are rejected, and the tool-permission gate is deferred (TODO(rfc010-permission-gate) — tools run with the executor's full authority). See packages/ui/acp/README.md for the full contract.