fix(adapters): MCP tool-gateway fidelity (PRJ-07..10, PRJ-13)

- search honors the optional query substring filter (PRJ-07)
- search excludes both Sub andPub ops per ADR-041/ADR-068; dead match
  arms removed (PRJ-08)
- batch returns {"results": [...]} with {isError, output|error} items;
  tool description states the shape (PRJ-09)
- structuredContent is always an object: non-object outputs wrapped as
  {"result": <output>} (PRJ-10)
- argument errors are CallError values (retryable always present);
  non-string operation no longer reports 'missing required field'
  (PRJ-13)

Verified: cargo test --all-features, cargo test, clippy -D warnings,
fmt --check

tasks/adapters/review-001-mcp-tool-fidelity.md

@@ -1,7 +1,7 @@
 ---
 id: review-001-mcp-tool-fidelity
 name: MCP tool-gateway runtime fidelity (PRJ-07, PRJ-08, PRJ-09, PRJ-10, PRJ-13)
-status: pending
+status: completed
 depends_on: [review-001-schema-internal-visibility]
 scope: narrow
 risk: low
@@ -39,11 +39,11 @@ this task covers the rest of the tool surface):
 
 ## Acceptance Criteria
 
-- [ ] `search` respects a `query` argument (test); `Pub` ops excluded from results (test)
-- [ ] Batch item doc matches the emitted shape (or shape changed to match — one way or the other, tested)
-- [ ] Non-object outputs wrapped into objects or documented as an exception; batch shape consistent
-- [ ] MCP argument errors carry `retryable` and truthful messages
-- [ ] `cargo test --all-features` passes
+- [x] `search` respects a `query` argument (test); `Pub` ops excluded from results (test)
+- [x] Batch item doc matches the emitted shape (or shape changed to match — one way or the other, tested)
+- [x] Non-object outputs wrapped into objects or documented as an exception; batch shape consistent
+- [x] MCP argument errors carry `retryable` and truthful messages
+- [x] `cargo test --all-features` passes
 
 ## References
 
@@ -58,4 +58,40 @@ this task covers the rest of the tool surface):
 
 ## Summary
 
-> Filled on completion.
+All five findings fixed in `src/adapters/to_mcp.rs`:
+
+- **PRJ-07**: `call_tool` extracts the optional `query` argument and
+  `handle_search` filters the listing by substring match on the
+  operation name (after the visibility/ACL filter — the query narrows
+  what the caller is allowed to see, never widens it).
+- **PRJ-08**: exclusion now covers both `"sub"` and `"pub"` (ADR-068 §1
+  and ADR-041 §2); the dead `"subscription"`/`"Sub"` match arms are
+  removed. A `search_excludes_pub_ops` test asserts the Pub op is
+  invisible to MCP discovery.
+- **PRJ-09**: shape decided over doc — `batch` now returns
+  `{"results": [...]}` where each entry is
+  `{"isError": bool, "output": ...}` on success or
+  `{"isError": true, "error": <CallError>}` on failure; the tool
+  description states exactly that (multiple dispatch-path failures in
+  one batch let the other items run to completion, so the old
+  "shaped like a `call` result" description was the wrong side to
+  keep).
+- **PRJ-10**: module doc documents the object guarantee: object outputs
+  pass through verbatim, non-object outputs are wrapped as
+  `{"result": <output>}` (`object_result`), applied consistently to
+  `call`'s `structuredContent` and to batch item `output` — so every
+  `structuredContent` is a JSON object and batch is never a top-level
+  array.
+- **PRJ-13**: all argument errors (`call`, `batch`, `schema`, and the
+  batch per-item errors) are `CallError` values serialized through the
+  same `call_error_to_structured_error` path, so `retryable` is always
+  present. `parse_call_arguments` now distinguishes a missing
+  `operation` ("missing required field") from a non-string one
+  ("must be a string, got <type>").
+
+Tests: `search_honors_query_substring_filter`,
+`search_excludes_pub_ops`, `call_wraps_non_object_output_into_object_
+structured_content`, `call_argument_errors_carry_retryable_and_truthy_
+messages`, `batch_returns_object_with_result_entries` (retryable +
+INVALID_INPUT per-item check); existing tests updated to the new
+shapes.