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[bug] Gemini schema sanitization misses properties/required when type is undefined #13148
Description
Bug Description
sanitizeGemini in transform.ts strips properties and required from non-object types, but misses the case where type is entirely undefined.
This is a follow-up edge case from #11889 / PR #11888.
Root Cause
The current check:
if (result.type && result.type !== "object") {
delete result.properties
delete result.required
}When type is undefined, result.type && ... short-circuits to false, so properties/required are not removed.
Reproduction
MCP tools like Notion MCP define schemas where type is omitted but properties/required are present:
{
"data": {
"description": "The data required for updating a page",
"properties": { "page_id": { "type": "string" } },
"required": ["page_id"]
}
}This causes:
Bad Request: GenerateContentRequest.tools[0].function_declarations[90].parameters.properties[data].properties: only allowed for OBJECT type
Expected Behavior
Schemas with properties/required but no type should be treated as implicit objects (per JSON Schema spec) and have type: "object" added.
Proposed Fix
// Add type "object" for schemas with properties/required but missing type
if (!result.type && (result.properties || result.required)) {
result.type = "object"
}Environment
- OpenCode v1.1.56
- Notion MCP Server
- Gemini model (google provider)
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fix(provider): infer type 'object' for schemas with properties but mi…
R44VC0RP commentedon Feb 11, 2026
Confirmed — good catch. PR #11888 fixed the case where
typeis explicitly non-object, but missed whentypeisundefined.Your proposed fix is correct. Per JSON Schema spec, a schema with
properties/requiredbut no explicittypeshould be treated as an implicit object. Addingtype: "object"in that case fixes the issue.The relevant code is in
packages/opencode/src/provider/transform.ts:796:Should add before this:
Feel free to open a PR with tests.
fix(google): sanitize unsupported JSON Schema keywords for Gemini API
github-actions commentedon Apr 13, 2026
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