Document the architecture and rewrite AGENTS.md

docs/architecture.md: layering, service map, event taxonomy, the
session/turn/step lifecycle, Cordis waterfall semantics, an extension
cookbook, the plugin sanity checklist mapping every MVP feature to its
extension mechanism, and the deferred-work TODO list (sub-agents,
persistence backends, compaction, DeepSeek V4 adapter, parallel tool
execution, streaming-protocol review).

AGENTS.md: repo layout, commands, conventions (dsh-* naming, ESM,
effect-based registrations, declaration merging, waterfall semantics),
and the vendoring policy pointer.
This commit is contained in:
Tianyi Cui
2026-06-11 10:55:05 +08:00
parent 53d1ef4a74
commit cacfae3cae
3 changed files with 401 additions and 2 deletions

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@@ -4,9 +4,80 @@ This is the monorepo for the DeepSeek Harness group. It currently hosts the code
## Architecture
This codebase is based on the **Cordis** framework. All necessary Cordis dependencies are copied into this monorepo as vendored source instead of being depended on via npm.
This codebase is based on the **Cordis** framework, built microkernel-style: **everything is a plugin**. All necessary Cordis dependencies are copied into this monorepo as vendored source (under `vendor/`) instead of being depended on via npm.
Read [docs/architecture.md](docs/architecture.md) before changing anything under `packages/` — it defines the service map, the event taxonomy, the session/turn/step lifecycle, and the plugin cookbook.
## Design Documents
- [Coding Harness MVP 需求分析](https://trtgsjkv6r.feishu.cn/wiki/ZwK6wfBE9i91V6kzMGYcgRGanxg) — requirement analysis for the initial MVP.
- [微内核Harness实现思路](https://trtgsjkv6r.feishu.cn/wiki/VS9Lw1kQki6mDJk2UHocyuphnsc) — discussion of the microkernel plugin-style architecture ("everything is a plugin").
## Repository Layout
```
vendor/ Vendored Cordis framework source (original npm names, private).
See vendor/README.md for the manifest, local-modification log,
and the upstream sync procedure. Do NOT edit casually — every
divergence must be logged there.
packages/ Harness packages, all named @deepseek-ai/dsh-<name>:
llm/ abstract LLM service + content-block vocabulary (no real adapter yet)
session/ event-sourced session log + in-memory store
system-prompt/ prompt-section + tool-schema assembly registry
tools/ tool registry + tools/execute waterfall
agent/ Agent interface, registry, agent/* event vocabulary
agent-loop/ THE concrete plugin: LoopAgent + the loop driver
examples/ Runnable demos (not workspaces). echo-agent = mock model + echo
tool + stdio UI + JSONL persistence, wired via cordis.yml.
docs/ architecture.md — the design doc.
scripts/ build.ts — dumble JS bundling for all packages.
```
## Commands
```sh
yarn install # Yarn 4 workspaces (node-modules linker), node >= 24
yarn test # vitest run (packages/*/tests/**/*.spec.ts)
yarn typecheck # tsc -b tsconfig.build.json (declarations only)
yarn build # typecheck + dumble JS bundles into each package's lib/
yarn demo # run examples/echo-agent (needs --expose-internals, the
# script passes it; type "echo hi" to see a tool call)
```
Dev/test/demo run **unbuilt** via tsx + the `paths` map in the root
`tsconfig.json` (`vitest` resolves through `tsconfig.test.json`). Building is
only needed for publishing/consumption outside the repo.
## Conventions
- **Package naming**: every npm package in this repo is `@deepseek-ai/dsh-<name>`
(vendored packages keep their upstream names and are `private: true`).
- **ESM everywhere** (`"type": "module"`); imports between workspace packages
use package names, never relative paths across package boundaries.
In-package imports use explicit `.ts` extensions (allowImportingTsExtensions).
- **`cordis` is a peerDependency** (+ devDependency) of every harness package,
mirroring upstream convention.
- **Registrations are effects**: anything a plugin contributes (adapter, tool,
section, agent, event listener) goes through `ctx.effect()` / `ctx.on()` so
disposal and HMR work. If you write a registry, `register()` must return the
disposer.
- **Typed events via declaration merging**: services declare their events in
`declare module 'cordis' { interface Events { … } }`, and their ctx key in
`interface Context`. Extensible unions use the merge-extensible-map pattern
(see `ContentBlockMap`, `MessageSourceMap`).
- **Waterfall semantics**: `ctx.waterfall` listeners receive `(...args, next)`
and MUST call `next()` to delegate; returning without it short-circuits.
This is the veto mechanism — use deliberately.
- **Plugins, not loop changes**: new behavior goes into a plugin on the
documented extension seams (see the plugin sanity checklist in
docs/architecture.md). Changing `agent-loop` requires updating that doc.
- **Tests**: vitest, colocated under `packages/<name>/tests/*.spec.ts`. Every
registry needs an HMR-safety test (dispose the contributing fiber, assert
cleanup).
## Vendoring Policy
`vendor/` packages are pinned source copies (manifest with upstream commit
SHAs in [vendor/README.md](vendor/README.md)). To update one, follow the sync
procedure there; re-apply (or retire) the logged local modifications and rerun
`yarn test && yarn build`.

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@@ -8,4 +8,12 @@ Monorepo for the DeepSeek Harness group.
## Development
This monorepo is built on the [Cordis](https://github.com/cordiverse/cordis) framework. See [AGENTS.md](AGENTS.md) for codebase conventions and agent instructions.
This monorepo is built on the [Cordis](https://github.com/cordiverse/cordis) framework (vendored as source under `vendor/`), microkernel-style: everything is a plugin.
```sh
yarn install
yarn test # vitest
yarn demo # runnable echo-agent example
```
See [AGENTS.md](AGENTS.md) for layout, commands, and conventions, and [docs/architecture.md](docs/architecture.md) for the design.

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docs/architecture.md Normal file
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# DeepSeek Harness Architecture
This document describes the phase-1 architecture of the DeepSeek Harness — the
foundation of **DeepSeek Code**. The governing principle, from the
[microkernel design discussion][microkernel-doc], is:
> **Microkernel approach. Everything is a plugin.**
The harness core is deliberately tiny: a handful of abstract services plus one
concrete plugin (the agent loop). Every product feature — tools, hooks,
compaction, sandboxing, UI, persistence, sub-agents, MCP, skills — is meant to
be written as a plugin against the extension surface described here, without
modifying the loop.
Requirement context: [Coding Harness MVP 需求分析][mvp-doc].
[microkernel-doc]: https://trtgsjkv6r.feishu.cn/wiki/VS9Lw1kQki6mDJk2UHocyuphnsc
[mvp-doc]: https://trtgsjkv6r.feishu.cn/wiki/ZwK6wfBE9i91V6kzMGYcgRGanxg
## Layering
```
┌─────────────────────────────────────────────────────────────┐
│ future plugins: tools, hooks, compaction, sandbox, UI, MCP… │
├─────────────────────────────────────────────────────────────┤
│ @deepseek-ai/dsh-agent-loop (the ONE concrete plugin) │
├─────────────────────────────────────────────────────────────┤
│ @deepseek-ai/dsh-agent (vocabulary + registry) │
│ @deepseek-ai/dsh-tools (registry + exec waterfall)│
│ @deepseek-ai/dsh-system-prompt (assembly registry) │
│ @deepseek-ai/dsh-session (event-sourced log) │
│ @deepseek-ai/dsh-llm (abstract model service) │
├─────────────────────────────────────────────────────────────┤
│ vendor/: cordis, loader, include, group, timer, hmr, │
│ logger-console, cosmokit, schemastery │
└─────────────────────────────────────────────────────────────┘
```
Dependency rule: plugins depend on interface packages, never on
`dsh-agent-loop`. The loop itself is swappable — UI/hook/tool plugins keep
working against the `dsh-agent` vocabulary if the loop is replaced.
## Service map
| ctx key | Class | Package | Role |
|---|---|---|---|
| `ctx.llm` | `LlmService` | dsh-llm | adapter registry; `stream()` / `streamBlocks()` / `generate()` |
| `ctx.sessions` | `SessionStore` | dsh-session | creates/holds event-sourced `Session`s |
| `ctx.systemPrompt` | `SystemPrompt` | dsh-system-prompt | ordered sections + tool schemas → `assemble()` |
| `ctx.tools` | `ToolRegistry` | dsh-tools | tool definitions; `execute()` through waterfall |
| `ctx.agents` | `AgentRegistry` | dsh-agent | live `Agent` handles |
| `ctx.agentLoop` | `AgentLoop` | dsh-agent-loop | creates `LoopAgent`s and drives their loops |
All registrations (`registerAdapter`, `section`, `tools`, `register`, …) go
through `ctx.effect()` and return disposers, so plugin hot-reload (vendored
HMR) and fiber disposal clean up automatically.
## The vocabulary (dsh-llm)
Messages are arrays of typed **content blocks** (`text`, `reasoning`,
`tool-call`, `tool-result`, `image`); the union is derived from the
merge-extensible `ContentBlockMap`, so plugins can add block types via
declaration merging. The same merge-extensible-map pattern is used for
`MessageSource`, `FinishReason`, `TurnTrigger`, and `TurnEndReason` — typed
sum types instead of strings.
Streaming is a raw chunk protocol (`block-start`, `text-delta`,
`reasoning-delta`, `tool-call-delta`, `block-end`, `usage`, `finish`).
`BlockAssembler` is the single shared implementation that assembles chunks
into blocks/messages; the loop logs raw chunks (replay fidelity) while feeding
the same chunks through an assembler.
`LlmAdapter` is the provider seam: subclass, implement `stream()`, call
`ctx.llm.registerAdapter(models, adapter)`.
**TODO**: the DeepSeek V4 adapter is the first real adapter (next phase); the
streaming protocol gets a careful review then.
## Event-sourced sessions (dsh-session)
A `Session` is an append-only log of typed `SessionEvent`s — the single source
of truth. The LLM message history is *derived* from the log
(`deriveMessages()`):
- `user/message` → user message
- `assistant/message` → assistant message (raw `assistant/chunk` events are
replay/UI data and are skipped in derivation)
- `tool/result` → user message carrying a `tool-result` block
- `context/message`, `steering/message` → user-role messages wrapped in a
tagged envelope (`<context source="…">…</context>`) at their chronological
position — the "system-reminder" pattern; models distinguish them from real
user prompts by the envelope. **TODO(review)**: revisit the envelope once a
real adapter exists.
Replay/fork = `ctx.sessions.create(id, seedEvents)`. Trace/telemetry = listen
to `session/event`.
**Durability seam**: `session/event` is a synchronous notification;
persistence plugins buffer (write-behind) and drain at the awaited
`session/flush` checkpoint the loop fires at every turn end (see
`examples/echo-agent/src/session-jsonl.ts` for the pattern).
**TODO**: real persistence backends (JSONL per session dir, sqlite) are a
future phase.
## Prompt assembly (dsh-system-prompt)
Plugins contribute `PromptSection`s (named, ordered, static or computed) and
tool-schema providers. `assemble()` returns a `PromptAssembly { sections,
tools }` through the `system-prompt/assemble` waterfall.
Tool schemas are deliberately **part of the assembly**: "what the model is
told it can do" is one coherent thing managed here, even though adapters
transmit schemas as the wire-level `tools` field rather than prompt text.
## Tool pipeline (dsh-tools)
`ToolRegistry.register()` takes schema + `execute()`. The registry feeds its
schemas into the system-prompt assembly automatically.
`execute()` runs through the **`tools/execute` waterfall** — the single seam
where sandbox, permission, hooks, and plan-mode plugins wrap or veto a call.
This collapses Claude Code's validate → PreToolUse → permission → execute →
PostToolUse pipeline into ordered waterfall listeners.
**TODO**: tool shapes get revisited when real tools land (e.g. a
concurrency-safety hint for parallel execution; phase 1 executes tool calls
sequentially).
## Agents (dsh-agent) and the loop (dsh-agent-loop)
`Agent` is the handle every plugin programs against:
- `send(content)` — queued message; starts a turn when idle, else next turn
- `steer(content)` — mid-turn injection, drained **between steps**; behaves
like `send` when idle
- `inject(content)` — in-session context (`context/message` event) without
triggering a turn; the next request sees it (Claude Code attachment /
system-reminder analog)
- `abort(reason)` — aborts the in-flight step via `AbortSignal`
- `session`, `status`, `options`
**TODO(sub-agents)**: `spawn`/`fork` land on `AgentLoop.create()` — fork seeds
the child Session with the parent's event log, spawn starts fresh; children
are ordinary `Agent` handles so `steer()` and event subscription work
uniformly. Inter-agent channels beyond these primitives are deliberately
deferred.
### Loop lifecycle (session / turn / step)
- **Session**: the whole event log of one agent.
- **Turn**: triggered by ≥1 queued message; runs steps until the model stops
requesting tools and no plugin requests continuation.
- **Step**: one model request + its tool executions.
```
forever:
wait for queued messages (idle)
TURN: drain queued → session('user/message'…) → 'turn/start' → emit agent/turn-start
STEP loop:
emit agent/step-start
assembly = ctx.systemPrompt.assemble() ⟵ waterfall system-prompt/assemble
req = {model, system, tools, messages: session.deriveMessages(), signal}
req = waterfall agent/request ⟵ hooks, compaction, model switch
stream ctx.llm.stream(req) ⟵ waterfall llm/stream (raw chunks)
session('assistant/chunk'); emit agent/stream-chunk
session('assistant/message', 'usage')
msg = waterfall agent/step-result ⟵ post-process before tool dispatch
each tool-call (sequential):
session('tool/call'); ctx.tools.execute() ⟵ waterfall tools/execute
session('tool/result')
drain steering → session('steering/message'); emit agent/steering
emit agent/step-end
cont = waterfall agent/turn-continuation(default = hadToolCalls || steered)
if !cont: break
session('turn/end'); emit agent/turn-end
await ctx.parallel('session/flush', session) ⟵ durability checkpoint
idle (emit agent/status) unless more queued
```
### Event taxonomy
Declared in `@deepseek-ai/dsh-agent` (so nothing depends on the loop package).
| Event | Mode | Purpose |
|---|---|---|
| `agent/created` / `agent/disposed` / `agent/status` / `agent/queued` | emit | lifecycle + inbox notifications |
| `agent/turn-start` / `agent/turn-end` / `agent/step-start` / `agent/step-end` | emit | boundaries |
| `agent/request` | **waterfall** | mutate the final `GenerateOptions` before the model call |
| `agent/stream-chunk` | emit | token-level UI/log feed |
| `agent/step-result` | **waterfall** | post-process the assistant message before tool dispatch |
| `agent/steering` | emit | steering content injected |
| `agent/turn-continuation` | **waterfall** | override the continue/stop decision |
| `agent/error` | emit | step/turn errors |
| `tools/execute` (dsh-tools) | **waterfall** | wrap/veto/sandbox tool execution |
| `llm/stream` / `llm/generate` (dsh-llm) | **waterfall** | model-call interception |
| `system-prompt/assemble` (dsh-system-prompt) | **waterfall** | mutate the assembly |
| `session/created` / `session/event` (dsh-session) | emit | session lifecycle + log feed |
| `session/flush` (dsh-session) | parallel (awaited) | durability checkpoint |
### Cordis waterfall semantics (important)
`ctx.waterfall` is **around-middleware**, not a value reducer. Each listener
receives `(...args, next)`:
- call `next()` to delegate to later listeners (and ultimately the core
behavior), possibly wrapping it;
- return a value **without** calling `next()` to short-circuit (veto);
- listeners run in registration order; `prepend: true` jumps the queue.
Mutate the passed-in object (e.g. `options.model = '…'`) or return a
replacement value — both compose.
## Plugin sanity checklist
Every MVP feature (including the TODO-marked ones), with the mechanism that
implements it **without modifying the loop**:
| MVP feature | Plugin mechanism |
|---|---|
| Hook system (user + project level) | listeners on `agent/request`, `agent/step-result`, `tools/execute`, `agent/turn-continuation`; a hooks plugin bridges config files to shell commands |
| `/goal` | force-continue via `agent/turn-continuation` + `steer()` reminders |
| `/loop` | on `agent/turn-end`, `send()` the next iteration; or force-continue |
| Dynamic workflow | orchestrator plugin on `agent/turn-end` / `agent/step-end` driving `send`/`steer` (+ sub-agents later) |
| Queued + steering messages | core `Agent.send()` / `Agent.steer()` |
| Context compaction (auto + manual) | wrap `agent/request`: measure tokens, rewrite `req.messages`, append merged `compaction/*` session events; manual = a command plugin invoking the same routine |
| System prompt configurability | `ctx.systemPrompt.section()` with ordering |
| AGENTS.md (root) | a section provider reading the file |
| AGENTS.md (subdir, on-touch) + file-change notices | `agent.inject()` from a watcher / tool-result listener |
| Built-in tools (Read/Write/Edit/Bash/…) | `ctx.tools.register()`; schemas flow into the assembly automatically |
| ToolSearch / progressive disclosure | wrap `agent/request`, filter `req.tools` |
| Tool sandbox (landlock / sandbox-exec) | wrap `tools/execute` |
| Permission system / AskUserQuestion | wrap `tools/execute` (veto or ask); register an ask tool |
| Plan mode | wrap `tools/execute` (deny writes) + `agent/request` (inject mode prompt) |
| Sub-agents (spawn / fork / steer) | TODO seam on `AgentLoop.create()`; fork = seed Session with parent events; `steer()` on the child handle |
| MCP | one plugin per server: discover tools → `ctx.tools.register()` |
| Skills | section + tool registration; `inject()` skill content on invocation |
| Memory | section provider + tool |
| Scheduled tasks (cron) | plugin registers model-callable scheduling tools; timer fires → `send(…, {source: {kind: 'cron', …}})` when idle / `inject()` notification when busy |
| UI (GUI; CLI emits JSONL) | listen `agent/stream-chunk` + `session/event`; input → `send()` |
| Telemetry / replayable trace | `session/event` → JSONL; replay = `sessions.create(id, seed)` |
| DeepSeek V4 (and other) models | `LlmAdapter` subclass via `registerAdapter` |
| Plugin hot-reload | every registration is a `ctx.effect` → vendored HMR just works |
## Extension cookbook
### A tool plugin
```ts
import type { Context } from 'cordis'
export const name = 'my-tool'
export const inject = ['tools']
export function apply(ctx: Context) {
ctx.tools.register({
name: 'read_file',
description: 'Read a file from disk.',
parameters: { type: 'object', properties: { path: { type: 'string' } }, required: ['path'] },
async execute(args: any) {
const text = await readFile(args.path, 'utf8')
return [{ type: 'text', text }]
},
})
}
```
### A hook plugin (permission gate)
```ts
export const name = 'permission-gate'
export function apply(ctx: Context) {
ctx.on('tools/execute', async (exec, next) => {
if (!(await isAllowed(exec))) {
return {
callId: exec.callId,
content: [{ type: 'text', text: 'Denied by policy.' }],
isError: true,
}
}
return next()
})
}
```
### A UI plugin
```ts
export const name = 'my-ui'
export const inject = ['agents']
export function apply(ctx: Context) {
ctx.on('agent/stream-chunk', (agent, turn, step, chunk) => {
if (chunk.type === 'text-delta') render(chunk.text)
})
onUserInput(text => ctx.agents.get('main')?.send([{ type: 'text', text }]))
}
```
A complete runnable wiring lives in [`examples/echo-agent`](../examples/echo-agent)
(mock model + echo tool + stdio UI + JSONL persistence, loaded from
`cordis.yml` with HMR).
## Deferred work (TODO)
Tracked here deliberately — each is designed-for but not implemented:
- **Sub-agent spawn/fork semantics** (seam: `AgentLoop.create()`); inter-agent
channels beyond `send`/`steer`/events.
- **Persistence backends** (JSONL session dirs, sqlite) on the
`session/event` + `session/flush` seam.
- **Compaction implementation** (auto thresholds, summarization prompts) on
the `agent/request` seam, with its session-event types added by declaration
merging.
- **DeepSeek V4 adapter** — first real `LlmAdapter`; triggers the
streaming-protocol review (`TODO(review)` markers in dsh-llm).
- **Parallel tool execution** (concurrency-safety hints on ToolDefinition).
- **Session branching/tree** (pi-style entry tree) if needed beyond seed-based
forking.
- **Session event vocabulary review** once the loop and a persistence plugin
coexist (`TODO(review)` in dsh-session).