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fix: add items to array params for OpenAI strict tool schema compat#904

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fix: add items to array params for OpenAI strict tool schema compat#904
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lubos-buracinsky:fix/array-params-items-openai-strict-compat

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@lubos-buracinsky lubos-buracinsky commented May 12, 2026

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OpenAI Structured Outputs strict mode (used by Codex CLI / gpt-5.5 route) rejects JSON Schema arrays without an items clause:

Invalid schema for function gbrain__extract_facts: In context=('properties', 'entity_hints'), array schema missing items.

Fixes

Two issues, two-line fix total:

  1. src/core/operations.ts line 2437extract_facts.entity_hints had { type: 'array', description: ... } without items. Added items: { type: 'string' } to align with the established gbrain convention (e.g. log_ingest.pages_updated already specifies items the same way).

  2. src/commands/serve-http.ts line 821 — inline schema generator in ListToolsRequestSchema handler did not propagate items from op.params definitions, even though the parallel buildToolDefs in src/mcp/tool-defs.ts does. Added ...(v.items ? { items: { type: v.items.type } } : {}) spread to match.

Why this matters

Bare { "type": "array" } is valid per JSON Schema 2020-12 (mixed-type arrays are allowed), but OpenAI Structured Outputs strict mode requires items. Without this fix, any gbrain serve --http deployment is unusable from OpenAI strict-mode callers (Codex CLI, ChatGPT via OAuth, etc.).

Reproducer

gbrain serve --http --port 3131
curl -H "Authorization: Bearer <token>" -X POST http://localhost:3131/mcp \
  -d '{"jsonrpc":"2.0","method":"tools/list","id":1}'
# entity_hints schema missing items, OpenAI strict-mode rejects on tools/call

Test plan

  • Verified end-to-end: OpenAI Codex CLI agent successfully calls gbrain__search via MCP through gbrain HTTP server (was rejected with "array schema missing items" before fix)
  • No new tests required (existing tools-list contract upheld)

References

🤖 Discovered + fixed during Phase C deployment of gbrain × OpenClaw integration. Generated with Claude Code.


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OpenAI Structured Outputs strict mode (used by Codex CLI / gpt-5.5
route) rejects JSON Schema arrays without an items clause:

  Invalid schema for function gbrain__extract_facts: In
  context=('properties', 'entity_hints'), array schema missing items.

Bare { "type": "array" } is valid per JSON Schema 2020-12 (mixed-type
arrays are allowed), but strict mode requires items. Most gbrain
operations already follow this pattern (e.g. log_ingest.pages_updated
uses items: { type: 'string' }), so this aligns extract_facts with
the established convention.

Also fix: serve-http.ts has an inline schema generator (lines 815-822)
that duplicates buildToolDefs in tool-defs.ts but does not propagate
the items field. Added matching spread so HTTP MCP returns the same
schema shape as stdio MCP.

Reproducer:
  gbrain serve --http --port 3131
  curl -H "Authorization: Bearer <token>" -X POST \
       http://localhost:3131/mcp \
       -d '{"jsonrpc":"2.0","method":"tools/list","id":1}'
  -> entity_hints schema missing items, OpenAI strict-mode rejects.

Refs:
  https://json-schema.org/understanding-json-schema/reference/array
  https://platform.openai.com/docs/guides/structured-outputs
garrytan added a commit that referenced this pull request May 17, 2026
… placement (#1053)

* refactor(mcp): centralize ParamDef→JSON Schema via shared paramDefToSchema

Three duplicate inline mappers existed across the MCP surface:
- src/mcp/tool-defs.ts (stdio MCP buildToolDefs)
- src/commands/serve-http.ts:837 (live HTTP MCP tools/list)
- src/core/minions/tools/brain-allowlist.ts:84 (subagent tool registry)

Each had subtly different items propagation. The HTTP MCP variant dropped
items entirely, leaving extract_facts.entity_hints broken for OAuth-
authenticated remote agents even after a buildToolDefs-only patch. The
subagent variant propagated one level of items but used the same shallow
shape so nested arrays would silently drop.

Extract a single recursive paramDefToSchema helper exported from
src/mcp/tool-defs.ts and have all three mappers consume it. Closes the
bug class at the architecture level instead of patching one site at a
time. The helper copies type, description, enum, default, and recursively
rebuilds items so array-of-arrays preserves inner shape.

Key ordering (type, description, enum, default, items) matches the
pre-v0.34 inline mappers so JSON.stringify output stays byte-stable for
every existing operation that does not use nested arrays.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(schema): add items to extract_facts.entity_hints and handle-to-tweet candidates

Two array fields shipped without the items property required by JSON
Schema. Strict-mode validators (Gemini Pro structured outputs, OpenAI
strict tool definitions) reject the entire schema when any type:'array'
lacks items. Downstream agents on those providers couldn't use
extract_facts or the x_handle_to_tweet resolver.

extract_facts.entity_hints — declared items: { type: 'string' } matching
the handler at src/core/operations.ts:2733 which already coerces the
runtime value to string[].

handle_to_tweet outputSchema.candidates — full XTweetCandidate spec
including required + additionalProperties: false. The XTweetCandidate
TypeScript interface declares all five fields as required; without
required in the JSON Schema, a validator would accept {} as a valid
candidate. additionalProperties: false closes the OpenAI strict-mode
contract.

19 community PRs (#1028 #999 #980 #979 #910 #904 #847 #832 #863 #862
#812 for entity_hints; #910 caught candidates) converged on these
locations. This wave cherry-picks the deepest variant (#910 surfaced
both bugs) and centralizes via the paramDefToSchema helper from the
preceding commit so the live HTTP MCP tools/list path is also fixed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-Authored-By: DmitryBMsk (PR #910)

* fix(git-remote): move --no-recurse-submodules after the subcommand verb

Git CLI accepts two flag positions:
  git [global -c flags] <subcommand> [subcommand flags] [args]

Global -c config flags belong before the verb. Subcommand-specific
flags (like --no-recurse-submodules) belong after. Pre-v0.34
GIT_SSRF_FLAGS spliced both kinds before the verb, so cloneRepo
invoked:
  git -c http.followRedirects=false ... --no-recurse-submodules clone URL DIR

Real git rejects this with exit 129 ("unknown option:
--no-recurse-submodules") because --no-recurse-submodules is a clone
subcommand flag, not a global config flag. Every remote-source clone
broke in production from v0.28 onward. The fake-git harness in
test/git-remote.test.ts exits 0 regardless of argv shape, which is
why CI never caught it.

Split GIT_SSRF_FLAGS (3 -c config flags, spread BEFORE the verb) from
GIT_SSRF_SUBCOMMAND_FLAGS (--no-recurse-submodules, spread AFTER the
verb). cloneRepo and pullRepo both spread the new constant after
their respective verbs. The constant names signal the position rule
so future additions land in the right place.

7 community PRs converged on this location (#1023 #1020 #985 #963
#846 #842#800 doesn't exist). This wave cherry-picks the semantic-
constant approach from #846's GIT_SSRF_SUBCOMMAND_FLAGS name (the
clearest signal of the position rule).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(mcp+git+resolvers): structural array-items + subcommand-position guards

Three new tests / test groups close the bug classes the wave fixes:

test/mcp-tool-defs.test.ts — recursive structural guard walks every
operation's inputSchema and fails with a property path if any
type:'array' lacks items.type. Explicit fixture assertions for
extract_facts.entity_hints.items.type and a synthetic nested-array
ParamDef pinning items.items.type recursion. Without the explicit
fixtures the legacyInlineMap byte-equality test is mirror-theater —
mirroring both sides of the equality preserves the blind spot.

test/git-remote.test.ts — split snapshot test into GIT_SSRF_FLAGS
(3 global -c entries) and GIT_SSRF_SUBCOMMAND_FLAGS
(--no-recurse-submodules). cloneRepo + pullRepo argv tests now assert
the subcommand flag appears AFTER the verb index. Pre-v0.34 the
pinned argv slice prefix included --no-recurse-submodules, which
baked the bug into the test suite (codex catch).

test/resolvers.test.ts — recursive walk over both inputSchema AND
outputSchema for builtin resolvers (xHandleToTweetResolver,
urlReachableResolver). Explicit imports rather than
getDefaultRegistry(), which starts empty until commands/resolvers.ts
runs — codex catch on a hollow-walk failure mode. Dedicated case
pins candidates items shape including required + additionalProperties.

Reference legacyInlineMap in mcp-tool-defs.test.ts mirrors the new
recursive paramDefToSchema helper. No current op uses nested arrays so
the byte-equality test stays green for every existing operation.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(e2e): raise rerank timeouts for ZE live cold-start

The first rerank call of a CI run hits ZeroEntropy's cold-start latency
(observed ~5-6s on Tier 2 LLM Skills runners; subsequent calls < 500ms).
Two timeouts fired simultaneously at ~5s:

1. bun:test's default 5000ms per-test timeout caused (fail).
2. gateway.rerank's DEFAULT_RERANK_TIMEOUT_MS = 5000 fired right after,
   reported as "Unhandled error between tests".

The next rerank test (top_n=2) ran in 409ms because the API was already
warm. Cold-start is the only issue.

Pass explicit timeoutMs to each rerank() call and a longer per-test
timeout (30s) on both ZE rerank tests. Production DEFAULT_RERANK_TIMEOUT_MS
stays at 5s for the search hot path — these E2E tests bypass it locally
without changing the default that protects user latency.

Unrelated to the fix-wave in this PR (mcp-tool-defs + git-remote + resolver
guards). Lands here to keep Tier 2 LLM Skills green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore: bump version and changelog (v0.35.2.0)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* docs: sync for v0.35.2.0

Update CLAUDE.md Key files annotations for the v0.35.2.0 fix wave:

- src/mcp/tool-defs.ts: document new exported recursive paramDefToSchema
  helper and the three-consumer centralization (stdio MCP, HTTP MCP
  tools/list, subagent registry).
- src/core/minions/tools/brain-allowlist.ts: paramsToInputSchema now
  consumes the shared helper.
- src/commands/serve-http.ts: tools/list handler now consumes the shared
  helper (closes the HTTP MCP items-dropped bug class).
- src/core/git-remote.ts: new entry. Documents the GIT_SSRF_FLAGS (global
  config, pre-verb) vs GIT_SSRF_SUBCOMMAND_FLAGS (subcommand-scoped,
  post-verb) split, the 7-month silent regression, and the position-anchored
  regression guard in test/git-remote.test.ts.

Regenerated llms-full.txt to match.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* chore: rebump version to v0.35.3.0

Queue moved while this PR was open — v0.35.2.0 was claimed by master's
v0.35.1.0 sibling work. Advancing one slot. No code changes; only:
- VERSION + package.json: 0.35.2.0 → 0.35.3.0
- CHANGELOG.md: rewritten header + inline references
- CLAUDE.md: rewritten 4 key-file annotations
- llms-full.txt + llms.txt: regenerated to mirror CLAUDE.md

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
@garrytan

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Thanks @lubos-buracinskyextract_facts.entity_hints (and the other MCP array-schema items fixes) already ship in master as of v0.35.3.0. The shared mapper is paramDefToSchema in src/mcp/tool-defs.ts (used by stdio MCP, HTTP MCP, and the subagent registry); test/mcp-tool-defs.test.ts walks every array param and fails the suite if any lacks items.type. If your install is still hitting this on next gbrain upgrade, please reopen with the output of gbrain doctor --json.

Closing as already-shipped. Real appreciation for chasing this — the same bug was independently reported by ~12 contributors which is exactly the kind of signal that gets the structural fix prioritized.

@garrytan garrytan closed this May 18, 2026
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