fix(acp): break self-referential $ref cycles before Code Mode schema - #10469
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lifeizhou-ap merged 1 commit intoJul 15, 2026
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…codegen
pctx_code_mode eagerly converts every registered tool's JSON Schema into a
TypeScript type signature by following $refs through the schema's
$defs/definitions map. That walk (pctx_codegen::SchemaType::type_signature)
has no cycle detection or depth limit, so a self-referential schema -- e.g.
the generic "any JSON value" $defs entry some MCP servers (FastMCP/Pydantic)
emit via additionalProperties: {"$ref": "#/$defs/Any"} -- recurses forever
and aborts the whole goose serve process with a stack overflow the moment
such a tool is registered with the Code Mode extension enabled.
Sanitize tool input/output schemas before handing them to pctx: build the
$defs reference graph, detect cycles, and neutralize the specific $refs that
close a cycle with a permissive `{}` schema. This keeps pctx's recursion
finite regardless of what an external MCP server sends, at the cost of type
precision on the rare malformed/recursive branch only.
Fixes aaif-goose#10256
Abhijay007
requested review from
DOsinga,
The-Best-Codes,
alexhancock and
lifeizhou-ap
July 14, 2026 20:06
The-Best-Codes
approved these changes
Jul 14, 2026
lifeizhou-ap
approved these changes
Jul 15, 2026
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Fixes #10256
Summary
pctx_code_mode eagerly converts every registered tool's JSON Schema into a TypeScript type signature by following $refs through the schema's $defs/definitions map. That walk (pctx_codegen::SchemaType::type_signature) has no cycle detection or depth limit, so a self-referential schema -- e.g. the generic "any JSON value" $defs entry some MCP servers (FastMCP/Pydantic) emit via additionalProperties: {"$ref": "#/$defs/Any"} -- recurses forever and aborts the whole goose serve process with a stack overflow the moment such a tool is registered with the Code Mode extension enabled.
Sanitize tool input/output schemas before handing them to pctx: build the $defs reference graph, detect cycles, and neutralize the specific $refs that close a cycle with a permissive
{}schema. This keeps pctx's recursion finite regardless of what an external MCP server sends, at the cost of type precision on the rare malformed/recursive branch only.Testing
manual and unit