The generic tool_call(name, arguments: object) bridge hides a deferred tool's
real parameter schema from provider-native validation. Before this, only
top-level required-key absence was checked, so invalid enums, wrong types,
nested required fields and forbidden extra properties reached the handler
or MCP server. Now the call is coerced (same coerce_tool_args path normal
dispatch uses) and validated with the schema's declared JSON Schema draft;
failures return the path, constraint and parameters schema so the model
repairs the call in one round-trip. Fails open on missing/malformed schemas,
external $ref, or missing jsonschema.
Fixes#73175
Salvaged from #73179 onto current main (post core-tool deferral #97979).
Co-authored-by: teknium1 <teknium@nousresearch.com>
DragonnZhang
9514d354ca