## Why
MCP request failures and tool errors reported only through `codex/telemetry` metadata previously received an `unknown` error code, obscuring the failure category.
## What changed
- Classify typed request failures into bounded codes such as `request_timeout`, `transport_closed`, and `protocol_error`, and carry them into MCP call metrics and spans before errors become strings.
- Preserve typed timeouts when a prepared tool call exhausts its deadline during trusted access lookup.
- Accept allowlisted `error_code` values from `codex/telemetry` as a fallback after structured content and connector authentication metadata. Keep model output unchanged and ignore unrecognized metadata codes.
## Testing
Add coverage for typed errors wrapped in context, prepared-call timeout classification, metadata precedence and rejection, unchanged model output, and exported span error attributes.
GitOrigin-RevId: d7a440a6c9119b8a07a7f1fad697eb25af506f00
Anthony Tafoya
12fd621f62