# Sprint 133 Plan: MCP Tool Contract Conformance and Schema Drift Prevention

## Context

Tool names alone are insufficient; input/output contracts must remain stable.
Sprint 133 enforces deterministic contract conformance for MCP tools.

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## Goals

1. Model and validate tool input/output contracts as first-class artifacts
2. Detect contract drift against baselines with structured diffs
3. Gate contract-breaking changes behind explicit compatibility policy
4. Export conformance reports for release workflows

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## Steps

### Step 1569: MCP tool contract schema v1 model (10 tests)
### Step 1570: Input schema canonicalization model (10 tests)
### Step 1571: Output payload shape profiler model (10 tests)
### Step 1572: Contract drift classifier (`compatible`, `warning`, `breaking`) (10 tests)
### Step 1573: `whetstone_export_tool_contracts` MCP tool (8 tests)
### Step 1574: `whetstone_validate_tool_contracts` MCP tool (8 tests)
### Step 1575: Compatibility waiver policy bindings (8 tests)
### Step 1576: Contract conformance score model (8 tests)
### Step 1577: Contract conformance report artifact (8 tests)
### Step 1578: Sprint 133 integration summary + regression (8 tests)

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## Architecture Gate

- Contract canonicalization must be deterministic
- Breaking changes must emit explicit structured reasons
- Validation outputs must remain machine-readable and auditable
- Max 600 lines per header