Follow-up: make flat error_code terminal detection advisory-safe

[bokelley]

Argus follow-up from #2229.\n\nIn src/lib/utils/response-unwrapper.ts, the new flat error_code branch in isTerminalAdcpError is unconditional, while the existing errors[] branch defers to hasAdvisorySuccessPayload. Since success schemas are passthrough, a conformant success that echoes a stray top-level error_code string could be classified terminal and skip validation.\n\nSuggested fix: gate the flat error_code branch on !hasAdvisorySuccessPayload(obj, toolName) for symmetry with the array arm, then add a regression covering a success payload with advisory/stray error_code.\n\nNon-blocking follow-up from merged PR #2229.

[bokelley]

Triage

Classification: Bug
Bucket(s): library
Status: ready-to-implement

What the experts said:

• code-reviewer: approve fix — one-liner achieves exact symmetry with the errors[] arm; callers without toolName are unaffected; fix does not mask real terminal errors (status/adcp_error guards precede it).
• dx-expert: approve fix — all findings are nits (JSDoc, changeset wording, additional test matrix); no behavior change for adopters who omit toolName.

My take: Both experts converge with no blockers. The change is non-breaking in practice — toolName-absent callers see no change; the fix only affects the narrow case where a success payload echoes a stray error_code, which the current code mishandles by short-circuiting before schema validation.

Implementation scope:

• src/lib/utils/response-unwrapper.ts line 194: change if (typeof obj?.error_code === 'string') return true; → if (typeof obj?.error_code === 'string' && !hasAdvisorySuccessPayload(obj, toolName)) return true;
• test/lib/response-unwrapper.test.js: add regression — a get_products success payload + error_code: 'STRAY' must return false from isTerminalAdcpError(..., 'get_products') and reach schema validation via unwrapProtocolResponse; also assert isTerminalAdcpError(response) (no toolName) still returns true.
• JSDoc on isTerminalAdcpError: note that toolName activates the advisory guard for both the errors[] and error_code arms.
• Changeset: patch — call out the narrow behavior change so adopters auditing existing usages can audit them.
• Run npm run ci:quick before push.

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Triaged by Claude Code. Session: https://claude.ai/code/session_01VbNqRpbzDaHXk72gjdoxGj

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