# Code Review: Step 1 — Design the range-write contract

Verdict: APPROVE

I ran `git diff 9594870..HEAD --name-only`, reviewed the full diff and changed files, ran `git diff --check 9594870..HEAD`, and ran `go test ./internal/tools -run 'Unavailable|DateRange|Event'`.

`git diff --check` is clean. The targeted test command still fails to compile on the intentionally missing Step 2 implementation symbols (`newAddUnavailableDateRangeTool`, `addUnavailableDateRangeExternalID`, etc.), which is expected for this Step 1 TDD state.

## Findings

No blocking findings. The added failing tests now pin the approved range-write contract closely enough for Step 2: schema metadata, allowed categories/aliases, inclusive range writes, deterministic idempotency keys, duplicate/conflict handling, terse/full shaping, validation-before-I/O, and mid-range write failure behavior.
