docs(rfc): sharpen agent-loop, timer, and leaf-config accuracy

Self-review against the actual source surfaced three imprecisions:

- agent-loop placement: the core bundle forwards agent-loop's `agents`
  list as its own config (default []), matching AgentLoop.Config, rather
  than hardcoding []. This is what lets a shared core coexist with stdio
  pre-creating `main` and acp pre-creating none — and it directly rebuts
  the reason base-core.yml gives today for keeping the loop out of core.
- timer is universal and stdout-safe, so it lives in the shared spine,
  not the per-app front-door cluster (only logger + hmr are app-specific).
- model/systemPrompt land in different places per app (stdio onto the
  pre-created agent, acp onto the bridge plugin), routed by the app
  package's own Config — not a single uniform bundle entry.
This commit is contained in:
Tianyi Cui
2026-06-20 23:25:11 +08:00
parent 034779d761
commit d9c9c5d403

View File

@@ -4,18 +4,18 @@ Status: proposed
## Problem
An example folder is supposed to be *thin* — the variable wiring of a demo, not the demo's machinery. Today it is thick. Each example carries a hand-rolled `start.ts` boot bootstrap, an infra preamble (`logger`/`timer`/`hmr`), nested includes of three shared YAML fragments, and per-example `agent-loop`/persistence/system-prompt config. The actual app — the spine of services every agent needs — is spread across the leaf and the [base.yml](../../../../examples/base.yml) / [base-core.yml](../../../../examples/base-core.yml) / [acp-tail.yml](../../../../examples/acp-agent/acp-tail.yml) includes.
An example folder is supposed to be *thin* — the variable wiring of a demo, not the demo's machinery. Today it is thick. Each example carries a hand-rolled `start.ts` boot bootstrap, an infra preamble (`timer`, and — for the stdio demos — `logger` + `hmr`), nested includes of three shared YAML fragments, and per-example `agent-loop`/persistence/system-prompt config. The actual app — the spine of services every agent needs — is spread across the leaf and the [base.yml](../../../../examples/base.yml) / [base-core.yml](../../../../examples/base-core.yml) / [acp-tail.yml](../../../../examples/acp-agent/acp-tail.yml) includes.
The deeper problem is a **coupled front-door cluster** that lives at the leaf with nothing enforcing it. Choosing the ACP bridge over `ui-stdio` is not one swappable line: an ACP server must **drop the stdout console logger** (stdout is the JSON-RPC channel — a stray log corrupts the frames), omit `hmr` (the editor owns the subprocess), and pre-create **no** agents (ACP `session/new` creates them on demand), whereas the stdio app needs a console logger, `hmr`, and a pre-created `main`. Today that coupling is enforced only by prose warnings in [acp-agent/cordis.yml](../../../../examples/acp-agent/cordis.yml) and [base-core.yml](../../../../examples/base-core.yml). A leaf that wires a console logger into the ACP config is a one-line, comment-only mistake away — exactly the [stdout-purity footgun](../../implemented/feature/2026-06-18-acp-terminal-and-tool-rendering.md) the examples guard by hand. The three `start.ts` files also duplicate the Loader-boot tail, the `.env` loader, and (for ACP) snapshot-mode branching and the stdin-dispose lifecycle.
The deeper problem is a **coupled front-door cluster** that lives at the leaf with nothing enforcing it. Choosing the ACP bridge over `ui-stdio` is not one swappable line: an ACP server must **drop the stdout console logger** (stdout is the JSON-RPC channel — a stray log corrupts the frames), omit `hmr` (the editor owns the subprocess), and pre-create **no** agents (ACP `session/new` creates them on demand), whereas the stdio app needs a console logger, `hmr`, and a pre-created `main`. (`timer` is the one infra plugin common to both — it writes nothing to stdout — so it belongs in the shared spine, not the cluster.) Today that coupling is enforced only by prose warnings in [acp-agent/cordis.yml](../../../../examples/acp-agent/cordis.yml) and [base-core.yml](../../../../examples/base-core.yml). A leaf that wires a console logger into the ACP config is a one-line, comment-only mistake away — exactly the [stdout-purity footgun](../../implemented/feature/2026-06-18-acp-terminal-and-tool-rendering.md) the examples guard by hand. The three `start.ts` files also duplicate the Loader-boot tail, the `.env` loader, and (for ACP) snapshot-mode branching and the stdin-dispose lifecycle.
## Proposal
Make each example **mostly an invocation of an app package**, splitting the wiring along the existing [interface / implementation / consumer seam](../../implemented/architecture/2026-06-13-capability-seams.md): the **app package owns the composition**, the leaf `cordis.yml` owns only the **swappable choices** (which LLM adapter, which bash executor, model, prompt, persistence root).
- **`@deepseek-ai/dsh-agent-core`** — a Cordis bundle plugin for the providerless, executor-less, UI-less spine: `llm` + sessions + system-prompt + tools + agents + invariants + `tool-bash` + `agent-loop` (neutral `agents: []`). This is today's [base-core.yml](../../../../examples/base-core.yml) **minus** `bash-local`, **plus** the loop, as code instead of a YAML include.
- **`@deepseek-ai/dsh-agent-core`** — a Cordis bundle plugin for the providerless, executor-less, UI-less spine: `timer` + `llm` + sessions + system-prompt + tools + agents + invariants + `tool-bash` + `agent-loop`. This is today's [base-core.yml](../../../../examples/base-core.yml) **minus** `bash-local`, **plus** `timer` and the loop, as code instead of a YAML include. The bundle **forwards** `agent-loop`'s `agents` list as its own config (default `[]`, exactly the existing `AgentLoop.Config` shape in [packages/agent-loop/src/index.ts](../../../../packages/agent-loop/src/index.ts)) — so each app supplies its own pre-created agents. This is precisely the reason [base-core.yml](../../../../examples/base-core.yml) gives today for keeping `agent-loop` *out* of the shared core ("the examples disagree — stdio needs a pre-created `main`, acp needs none"); forwarding the config dissolves that objection — the loop is shared, the agents list is per-app.
- **`@deepseek-ai/dsh-stdio-agent`** and **`@deepseek-ai/dsh-acp-agent`** — app packages, each consuming `dsh-agent-core` and **baking in its coupled front-door cluster**: stdio = `ui-stdio` + console logger + `hmr` + a pre-created `main`; acp = the `acp` bridge + **no stdout logger** + no `hmr` + no pre-created agents. The coupling becomes structurally unreachable from the leaf.
- **Drop `start.ts`.** Each app package exposes a `bin`; the `demo:*` scripts invoke it (e.g. `dsh-stdio-agent ./cordis.yml`). The Loader-boot tail, `.env` loading, snapshot-mode selection, and stdin-dispose lifecycle move into that bin, owned by the app.
- **Collapse each leaf `cordis.yml`** to backends + config: the LLM adapter (`llm-deepseek` with apiKey/models, or `llm-replay`), the bash executor (`bash-local`), and one app-bundle entry carrying model / systemPrompt / persistence root. ~4 entries, no infra preamble.
- **Collapse each leaf `cordis.yml`** to backends + config: the LLM adapter (`llm-deepseek` with apiKey/models, or `llm-replay`), the bash executor (`bash-local`), and one app-bundle entry carrying the app's config (model, system prompt, persistence root — surfaced as the app package's own `Config`, which routes each value to wherever the app wires it: stdio onto its pre-created agent, acp onto the bridge plugin). A handful of entries, no infra preamble.
- **Fold echo-agent onto `dsh-stdio-agent`**, swapping the LLM backend to the local `mock-llm` and adding the local `echo-tool` at the leaf — the clean demonstration of "swap the backend, keep the app". `mock-llm.ts` / `echo-tool.ts` stay as example-local teaching plugins.
- **Retire** [base.yml](../../../../examples/base.yml), [base-core.yml](../../../../examples/base-core.yml), and [acp-tail.yml](../../../../examples/acp-agent/acp-tail.yml) — the spine they shared now lives in `dsh-agent-core`.