# Task 03: Message Parity Harness

> Parity validation between legacy message formats and canonical representations is incomplete. Without full parity coverage, there is limited confidence that adapter behavior matches real session data.

- Skill: `tools-only/task-03-message-parity-harness` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add tools-only/task-03-message-parity-harness`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tools-only/task-03-message-parity-harness/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Productivity
- Author: tools-only (https://skillmd.com/u/tools-only)
- Updated: 2026-09-29
- Page: https://skillmd.com/skills/tools-only/task-03-message-parity-harness

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# Task 03: Message Parity Harness

## Summary
Parity validation between legacy message formats and canonical representations is incomplete. Without full parity coverage, there is limited confidence that adapter behavior matches real session data.

## Context
`tests/unit/types/test_adapter.py` includes limited parity checks and round-trip coverage, but `tests/parity/test_message_parity.py` does not exist. There is no validation against real historical session artifacts.

## Related Docs
- [PLAN.md](../../PLAN.md)
- [Architecture Refactor Status Research](../../memory-bank/research/2026-01-25_architecture-refactor-status.md)