# Session Log — Error diagnostics slice

**Session ID:** `2026-04-02T16-23-55Z-error-diagnostics-slice`  
**Requested by:** Stefan Broenner  
**Topic:** first diagnostics slice for error-handling parity, anchored by issue #585  
**Status:** ✅ Complete — additive parity slice recorded and focused validations are green

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## Team Summary

### McCauley (Lead)
- Conditionally approved the slice.
- Blocking decision: CLI must mirror MCP error-envelope fields.
- Advisory: prefer focused validation slices until the broader `ProgramTransport` session flake is isolated.

### Cheritto (Platform Dev)
- Implemented additive transport enrichment on shared `ServiceResponse`.
- Added `exceptionType`, `hresult`, and `innerError` without changing Core/COM behavior.
- Mirrored the same failure shape through MCP and CLI while preserving both `error` and `errorMessage` for compatibility.

### Nate (Tester)
- Added focused parity and protocol regressions around #585-style failures.
- Confirmed targeted CLI/MCP validations passed.
- Confirmed broader full-class MCP runs still show existing `ProgramTransport` / session flake noise, but focused protocol and range-format buckets passed.

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## Key Decisions

1. Treat this work as **hardening + diagnostic improvement**, not a blanket “bug fixed” claim.
2. Keep the first milestone **additive** at the transport/presentation layer.
3. Keep `error` for compatibility, add `errorMessage` as a mirror, and expose `isError` plus structured diagnostics in both CLI and MCP.
4. Use targeted regression slices for #585 follow-up work until the unrelated MCP session flake is handled separately.

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## Validation Snapshot

- ✅ `ServiceResponse` now carries additive `exceptionType`, `hresult`, and `innerError`
- ✅ CLI and MCP now both expose `error`, `errorMessage`, `isError`, and structured diagnostics
- ✅ Targeted #585-focused CLI/MCP validation buckets passed
- ✅ Focused protocol and range-format buckets passed
- ⚠️ Broader full-class MCP runs still contain pre-existing `ProgramTransport` / session flake noise outside this slice

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## Files Produced

- `.squad/orchestration-log/2026-04-02T16-23-55Z-cheritto.md`
- `.squad/orchestration-log/2026-04-02T16-23-55Z-nate.md`
- `.squad/orchestration-log/2026-04-02T16-23-55Z-mccauley.md`
- `.squad/log/2026-04-02T16-23-55Z-error-diagnostics-slice.md`

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**Recorded by:** Scribe  
**Timestamp:** 2026-04-02T16-23-55Z
