# AGENTS.md — Harness Packages

This directory contains all `@deepseek-ai/dsh-*` harness packages. When editing code here, follow these conventions:

- **Effect-based registrations**: every contribution (tool, section, adapter, agent, event listener) goes through `ctx.effect()` / `ctx.on()`, and `register()` methods return disposers. Never use bare arrays or manual cleanup.
- **Declaration merging**: services declare their ctx key in `declare module 'cordis' { interface Context { } }` and their events in `interface Events`. Merge-extensible maps (`ContentBlockMap`, `MessageSourceMap`, `FinishReasonMap`, `TurnTriggerMap`, `TurnEndReasonMap`, `SessionEventMap`) are how plugins add new variants.
- **Waterfall semantics**: `ctx.waterfall` listeners receive `(...args, next)`; call `next()` to delegate, or return without it to short-circuit (veto). Never call `next()` after returning.
- **Plugin export shape — namespace OR default, never both.** A *service* package exports the service class as `export default` (the Loader instantiates it). A *function/namespace* plugin exports `name` / `inject` / `Config` / `apply` as separate named exports and **must NOT add `export default`** — the cordis Loader's `unwrapExports` does `exports.default ?? exports`, so a stray default export collapses the module to the bare `apply` function and silently discards the `inject`/`name`/`Config` namespace, leaving the plugin with no injected services (it then throws `cannot get property … without inject` at load). See [docs/postmortem/0001](../docs/postmortem/0001-acp-default-export-drops-inject.md).
- **Read an optional (non-injected) service via `ctx.get(name)`, not `ctx.<name>`.** For a service a plugin reads opportunistically but deliberately leaves out of `static inject` (e.g. `AgentLoop` reading `sessionPersistence`), the `ctx.<name>` property proxy resolves by an ancestor-only fiber walk that throws when the call arrives through a foreign traceable shadow (the service lives on a sibling fiber). `ctx.get(name)` is the topology-independent global-store lookup, strict by default (an inactive/absent backend reads as `undefined` — prefer it over the `ctx.get(name, false)` overload, which also skips the active-state check). Services that ARE in `static inject` resolve fine via `ctx.<name>`. See [docs/postmortem/0001](../docs/postmortem/0001-acp-default-export-drops-inject.md).
- **Tests**: vitest in `packages/<group>/<pkg>/tests/*.spec.ts`. Every registry needs an HMR-safety test (register a plugin, dispose its fiber, assert cleanup). Err on the side of more tests — edge cases, error paths, event ordering, races. A plugin shipped via `cordis.yml` also needs at least one test that drives it through the REAL Loader/export path (hand-built `ctx.plugin({...})` mounts bypass `unwrapExports` and cannot catch a broken export shape) — see AGENTS.md § Defensive patterns "Line coverage is not behavior coverage". Real-API (with-key) e2e tests are cheap here (we are DeepSeek) and welcome — write many, especially smoke tests; see AGENTS.md § Secrets / .env.

Naming notes:
- A *service* `src/index.ts` exports the service class as `export default` + all public types; a *function/namespace plugin* `src/index.ts` exports `name`/`inject`/`Config`/`apply` as named exports and NO default (see the plugin-export-shape rule above)
- `src/types.ts` contain only types — no runtime code
- Tests live at package level under `tests/`, not `src/__tests__/`
- A package's README and module/JSDoc comments are part of the change: when you alter behavior (config keys, defaults, error codes, wire fields), update them in the same commit. CI runs `pnpm run doc-sync`, which typechecks fenced `ts` blocks in `packages/*/*.md` and `packages/*/*/*.md`, regenerates the cordis events/services catalog from the `interface Events` / `interface Context` declarations (failing if the committed copy is stale), and checks markdown wrapping across this file too — but it does NOT catch prose drift (config keys, defaults, error codes), so those stay on the author. A new event needs an `@mode` tag on its JSDoc (the catalog generator hard-errors without it — see the root AGENTS.md).

Read the per-package README.md for package-specific details: service API, events, extension points, TODOs.
