docs: classify loader smoke support surface

packages/README.md

@@ -27,7 +27,7 @@ Packages are grouped by modular role at `packages/<group>/<pkg>/`. The group dir
 | [`session-persistence/`](session-persistence/README.md) | Persistence capability family: the seam + JSONL/SQLite backends | Product — stable surface |
 | [`session-query/`](session-query/README.md) | Session retrieval family: logical corpus, surface records, and bounded exact reads | Product — stable surface |
 | [`ui/`](ui/README.md) | Editor/client integration surfaces: ACP bridge, JSON-RPC SDK server, app packages, user-approval and user-interaction seams, ask-user tool | Product — stable surface |
-| [`support/`](support/README.md) | Dev/test/example infrastructure (invariants, replay, Loader-smoke, and subagent test helpers) | Support — lower compatibility expectations |
+| [`support/`](support/README.md) | Support infrastructure (invariants, replay, Loader smokes) | Support — lower compatibility expectations |
 | [`util/`](util/README.md) | Low-level zero-dependency utilities shared across groups (the `Branded<B>` primitive) | Support — small, stable, harness-dep-free |
 
 The split is the point: a package's group says whether it is part of the product API or support/test/example infrastructure, so release and removal decisions do not treat every package as an equal public contract. New packages join an existing group; adding a new top-level group is a deliberate act (extend the group READMEs and this table).

packages/support/loader-smoke/README.md

@@ -5,3 +5,13 @@ Shared subprocess harness for keyless example smokes that boot the real stdio-ag
 Successful runs return stdout and stderr only after a zero exit. Non-zero exits and deadlines reject with both captured streams. `LOADER_SMOKE_TEST_TIMEOUT_MS` leaves Vitest enough room for the process-owned diagnostic timeout to fire first.
 
 This is support-tier test infrastructure, not product API. The consumers are the Loader-path smokes under `examples/{echo-agent,coding-agent,cordis-agent}`.
+
+## Model Experience
+
+None, as this test-only harness boots example processes and inspects their streams without changing an assembled model request.
+
+## Known Limitations and Deferred Work
+
+- **Only the unbuilt tsx/Loader path is exercised** — built-bin artifacts remain the responsibility of their separate e2e smokes.
+- **Captured stdout and stderr are unbounded** — a runaway child can consume memory until the deadline kills it.
+- **Timeout kills only the direct child** — a process tree spawned by a faulty fixture can outlive the smoke and needs external cleanup.

scripts/verify-package-readme-model-experience.ts

@@ -61,6 +61,7 @@ const SENTENCE_MODEL_EXPERIENCE: Readonly<Record<string, SentenceContract>> = {
   'packages/subagent/subagent-subprocess': { kind: 'indirect', reason: 'Only process-based subagent backends compose a child model request.' },
   'packages/support/acp-snapshot': { kind: 'none', reason: 'The test harness observes and normalizes transcripts without changing live requests.' },
   'packages/support/invariants': { kind: 'none', reason: 'The observer validates requests but never rewrites their context.' },
+  'packages/support/loader-smoke': { kind: 'none', reason: 'The test harness observes child-process streams without changing live requests.' },
   'packages/support/llm-replay': { kind: 'none', reason: 'The keyless adapter invokes no provider model.' },
   'packages/support/subagent-mock': { kind: 'indirect', reason: 'Only dsh-tool-subagent renders its configured test outcome.' },
   'packages/ui/acp-agent': { kind: 'indirect', reason: 'The app bundle delegates request composition to dsh-agent-core and dsh-acp.' },