review: the persona becomes the system-prompt plugin's deployment config

Review round 2 (tianyicui inline comments):

- dsh-system-prompt itself registers the harness:identity (-100) and
  deployment:persona (0) sections — they must survive a swapped loop
  plugin, so they leave dsh-agent-loop; the persona text is the plugin's
  own validated 'persona' config. The model/cwd variables STAY on the
  loop: runtime facts of the agents it drives.
- AgentOptions.systemPrompt is deleted with all its forwarding plumbing:
  the app configs' systemPrompt keys become 'persona' routed through
  dsh-agent-core (schema = z.intersect of the owners'), the ACP bridge
  and tool-subagent stop carrying persona configuration, and subagent
  children now render the deployment persona like every other agent.
- Example personas drop transport/interface trivia (ACP, CLI) — facts
  irrelevant to the model.
- Root CONTEXT.md removed (not idiomatic); its persona definition was
  wrong under the new ownership anyway.
- Docs, READMEs, the prompt-variables RFC, and generated catalogs
  updated; new loop test pins the assemble-waterfall escape valve
  (an emptied assembly sends NO system field).

packages/ui/stdio-agent/README.md

@@ -11,7 +11,7 @@ A terminal chat always wants the same cluster, so the package owns it rather tha
 | Plugin | Why it is here |
 |---|---|
 | `@cordisjs/plugin-logger-console` | the console logger — stdout is just the terminal here, so logging to it is correct (the ACP app must NOT have this) |
-| `@deepseek-ai/dsh-agent-core` | the spine, pre-creating a `main` agent from this app's `model`/`systemPrompt` |
+| `@deepseek-ai/dsh-agent-core` | the spine, pre-creating a `main` agent from this app's `model` and carrying its `persona` |
 | `@deepseek-ai/dsh-session-persistence-jsonl` | durable JSONL session log under `persistenceRoot` |
 | `stdio-chat` (in-package module) | the readline UI, bound to the `main` agent |
 
@@ -24,7 +24,7 @@ The leaf `cordis.yml` supplies only the **swappable backends** — an LLM adapte
 | Key | Default | Routed to |
 |---|---|---|
 | `model` | (required) | the pre-created `main` agent's model |
-| `systemPrompt` | (required) | the `main` agent's persona template (may reference `{{model}}`) |
+| `persona` | — | the deployment persona template (may reference `{{model}}`), routed to `dsh-system-prompt` |
 | `persistenceRoot` | `./.sessions` | the JSONL backend's root directory |
 | `welcome` | `ready.` | the stdin-chat banner |
 | `resumeSessionId` | — | resume a persisted session id instead of starting fresh (sourced from an env var in the leaf) |
@@ -54,7 +54,7 @@ The leaf `cordis.yml` supplies only the **swappable backends** — an LLM adapte
   name: '@deepseek-ai/dsh-stdio-agent'
   config:
     model: deepseek-v4-flash
-    systemPrompt: 'You are a CLI coding assistant powered by the {{model}} model.'
+    persona: 'You are a coding assistant powered by the {{model}} model.'
 ```
 
 Swap `llm-deepseek` for a `mock-llm` leaf plugin and you have the echo demo — "swap the backend, keep the app".

packages/ui/stdio-agent/src/index.ts

@@ -51,15 +51,16 @@ export const name = 'stdio-agent'
 
 /**
  * App config: the swappable per-demo values, each routed to where the app wires
- * it. `model`/`systemPrompt`/`resumeSessionId` configure the pre-created `main`
- * agent (through {@link @deepseek-ai/dsh-agent-core}'s forwarded `agents` list);
+ * it. `model`/`resumeSessionId` configure the pre-created `main` agent (through
+ * {@link @deepseek-ai/dsh-agent-core}'s forwarded `agents` list); `persona` is
+ * the deployment persona (forwarded to the system-prompt plugin);
  * `persistenceRoot` is the JSONL backend's directory; `welcome` is the UI banner.
  */
 export interface Config {
   /** Model name for the `main` agent (must have a registered adapter). */
   model: string
-  /** System prompt for the `main` agent. */
-  systemPrompt: string
+  /** Deployment persona (the system-prompt plugin's `persona` config). */
+  persona?: string
   /** Directory the JSONL session backend writes under. Defaults to `./.sessions`. */
   persistenceRoot?: string
   /** stdin-chat banner printed once on start. Defaults to `'ready.'`. */
@@ -74,7 +75,7 @@ export interface Config {
 
 export const Config: z<Config> = z.object({
   model: z.string().required(),
-  systemPrompt: z.string().required(),
+  persona: z.string(),
   persistenceRoot: z.string().default('./.sessions'),
   welcome: z.string().default('ready.'),
   resumeSessionId: z.string(),
@@ -83,17 +84,17 @@ export const Config: z<Config> = z.object({
 /**
  * Compose the spine with the stdio front door. The console logger comes first
  * (infra), then the agent-core bundle pre-creating the `main` agent from this
- * app's `model`/`systemPrompt`/`resumeSessionId`, then the JSONL backend, then
- * the readline UI bound to `main`. The `hmr` dev-reload plugin is a leaf
- * concern (see the module doc), so it is not mounted here.
+ * app's `model`/`resumeSessionId` with the deployment `persona`, then the JSONL
+ * backend, then the readline UI bound to `main`. The `hmr` dev-reload plugin is
+ * a leaf concern (see the module doc), so it is not mounted here.
  */
 export function apply(ctx: Context, config: Config): void {
   ctx.plugin(ConsoleExporter)
   ctx.plugin(agentCore, {
+    ...config.persona !== undefined ? { persona: config.persona } : {},
     agents: [{
       id: AgentId('main'),
       model: config.model,
-      systemPrompt: config.systemPrompt,
       ...config.resumeSessionId !== undefined ? { resumeSessionId: SessionId(config.resumeSessionId) } : {},
     }],
   })

packages/ui/stdio-agent/tests/stdio-agent.spec.ts

@@ -8,8 +8,9 @@ import * as stdioAgent from '../src/index.ts'
  * Unit coverage for the @deepseek-ai/dsh-stdio-agent app plugin: mounting it
  * composes the console logger, the agent-core spine (pre-creating the `main`
  * agent from the app config), the JSONL backend, and the readline UI in one
- * `ctx.plugin`. The forwarded `model`/`systemPrompt` reach the pre-created
- * agent; `persistenceRoot`/`welcome`/`resumeSessionId` route to their backends.
+ * `ctx.plugin`. The forwarded `model` reaches the pre-created agent and
+ * `persona` the system-prompt plugin; `persistenceRoot`/`welcome`/
+ * `resumeSessionId` route to their backends.
  *
  * `hmr` is NOT part of this plugin (it is a leaf entry — a Loader-only dev
  * plugin the in-process tier cannot import); the keyless echo smoke in
@@ -30,7 +31,7 @@ async function mount(config: stdioAgent.Config): Promise<Context> {
 
 describe('dsh-stdio-agent app', () => {
   it('composes the spine + front-door cluster and pre-creates the main agent', async () => {
-    const ctx = await mount({ model: 'mock', systemPrompt: 'hi', persistenceRoot: '/tmp/dsh-stdio-agent-spec' })
+    const ctx = await mount({ model: 'mock', persona: 'hi', persistenceRoot: '/tmp/dsh-stdio-agent-spec' })
     // The spine services (brought up by the agent-core bundle) are all present.
     expect(ctx.get('agents')).toBeDefined()
     expect(ctx.get('agentLoop')).toBeDefined()
@@ -46,7 +47,8 @@ describe('dsh-stdio-agent app', () => {
     // apply()'s last two lines are the ones that fire — covering a
     // schema-bypassing direct-mount caller.
     const ctx = new Context()
-    stdioAgent.apply(ctx, { model: 'mock', systemPrompt: 'hi' })
+    // No persona: covers the omitted-persona forwarding branch too.
+    stdioAgent.apply(ctx, { model: 'mock' })
     await new Promise(resolve => setTimeout(resolve, 80))
     expect(ctx.get('sessionPersistence')).toBeDefined()
     expect(ctx.get('agents')?.get(AgentId('main'))).toBeDefined()
@@ -59,7 +61,7 @@ describe('dsh-stdio-agent app', () => {
     // the branch that maps resumeSessionId through is what this covers.
     const ctx = await mount({
       model: 'mock',
-      systemPrompt: 'hi',
+      persona: 'hi',
       persistenceRoot: '/tmp/dsh-stdio-agent-spec-resume',
       resumeSessionId: 'no-such-session',
     })