[zcrew0x]

Fixes #13057
Closes #13477

Problem

When a tool parameter schema contains a property named "properties", "required", etc. (e.g. in Roblox Studio, Blender, JSON Patch, or delivery.pin):

{
  "type": "object",
  "properties": {
    "action": { "type": "string" },
    "properties": { "type": "array", "items": { "type": "string" } }
  },
  "required": ["action"]
}

Schema visitor functions in open-sse/translator/helpers/geminiHelper.ts (such as injectObjectType, addPlaceholders, cleanupRequired, etc.) traversed schemas by doing a blind for (const value of Object.values(record)). When visiting schema.properties, because record.type was undefined and record.properties (or record.required) existed, injectObjectType injected schema.properties.type = "object" directly into the property dictionary.

This corrupted the schema sent to Google CloudCode/Gemini:

{
  "type": "object",
  "properties": {
    "action": { "type": "string" },
    "properties": { "type": "array", "items": { "type": "string" } },
    "type": "object"  <-- Invalid schema property
  }
}

Google rejected the request with HTTP 400:

"Invalid value at 'request.tools[0].function_declarations[1].parameters.properties[2].value' (type.googleapis.com/google.cloud.aiplatform.master.Schema), 'object'"

Solution

1. Introduce forEachSubschema in geminiHelper.ts to traverse subschemas according to JSON Schema structure (descending into values of properties, patternProperties, $defs, definitions rather than treating the container maps as schema nodes).
2. Use forEachSubschema across all schema visitors in geminiHelper.ts (injectObjectType, addPlaceholders, cleanupRequired, normalizeAdditionalProperties, convertConstToEnum, convertEnumValuesToStrings, mergeAllOf, flattenAnyOfOneOf, and flattenTypeArrays).
3. Add regression unit test suite in tests/unit/gemini-schema-properties-name-collision-13057.test.ts covering both property named "properties" (fix(providers): Gemini schema sanitizer corrupts tools containing property named 'properties' (HTTP 400) & keepalive chunk desync in AI-SDK #13057) and property named "required" ([BUG] Antigravity (AGY) Provider Returns 400 Bad Request - Schema Incompatibility with Google Gemini Tools #13477).

[ekinnee]

@zcrew0x target release/v3.8.51 please

[zcrew0x]

@ekinnee Rebased onto release/v3.8.51 and changed target base branch to release/v3.8.51 as requested. All unit tests passing.

[sprintberlin]

Verified against the exact #13477 Stage payload

This PR also fixes the concrete Antigravity/Gemini 400 reported in #13477.

I replayed the exact captured Stage request shape locally through buildGeminiTools:

• target: antigravity/gemini-3.8-flash-tiered
• result on Stage: HTTP 400 before inference
• catalog: 62 tools
• culprit isolated by tool/property bisection: message (index 31), specifically delivery.pin
• delivery.pin is anyOf: [boolean, object]; the object branch has properties named enabled, notify, and required

On current release/v3.8.51, the sanitizer produces this invalid shape:

{
  "type": "object",
  "properties": {
    "enabled": { "type": "boolean" },
    "notify": { "type": "boolean" },
    "required": { "type": "boolean" },
    "type": "object"
  },
  "required": ["enabled"]
}

The last entry is the bug: injectObjectType treats the properties map itself as a schema node because that map contains a user property named required, then injects a phantom type: "object" inside the property map. Google's Schema proto rejects the string where it expects a property schema object.

At this PR's head (8e981974), the same captured tool becomes:

{
  "type": "object",
  "properties": {
    "enabled": { "type": "boolean" },
    "notify": { "type": "boolean" },
    "required": { "type": "boolean" }
  },
  "required": ["enabled"]
}

No phantom properties.type, and anyOf/oneOf are absent. I also ran the complete captured 62-tool catalog through this PR: all 62 declarations survive, no union keyword survives the Gemini cleaner, and no scalar type entry is injected into a properties map. Focused tests at this head are green: gemini-schema-properties-name-collision-13057, gemini-malformed-required-and-bare-map-12269, and gemini-helper — 38/38.

So #13477 is not a separate converter problem in this reproduced case; it is another real-world manifestation of #13057's unsafe schema-map traversal. Please consider adding Closes #13477 (or at least Related to #13477) and pinning the captured delivery.pin shape as an additional regression case. I will not open a competing PR for the same root cause.

[zcrew0x]

@sprintberlin Thank you for reproducing and validating against the #13477 stage payload! I have added the delivery.pin regression test case covering the required property name collision and updated the PR description to close #13477.

[zcrew0x]

Superseded by #13690 with clean history on release/v3.8.51 and the added regression test for #13477 (delivery.pin.required).