# Sprint 138 Plan: Distributed Orchestrator-to-MCP Handoff Consistency

## Context

As orchestration spreads across nodes, MCP handoffs must preserve deterministic
context and tool contracts. Sprint 138 seals handoff consistency.

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## Goals

1. Normalize orchestrator-to-MCP handoff packets across nodes
2. Preserve deterministic context slices and tool arguments
3. Detect handoff drift between submitter and executor nodes
4. Export handoff integrity evidence for distributed debugging

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## Steps

### Step 1619: Orchestrator MCP handoff packet schema (10 tests)
### Step 1620: Context slice canonicalization for handoffs (10 tests)
### Step 1621: Cross-node handoff drift detector model (10 tests)
### Step 1622: Distributed handoff replay verifier (10 tests)
### Step 1623: `whetstone_capture_handoff_packet` MCP tool (8 tests)
### Step 1624: `whetstone_verify_handoff_integrity` MCP tool (8 tests)
### Step 1625: `whetstone_list_handoff_divergences` MCP tool (8 tests)
### Step 1626: Handoff confidence scorer model (8 tests)
### Step 1627: Handoff integrity report artifact (8 tests)
### Step 1628: Sprint 138 integration summary + regression (8 tests)

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## Architecture Gate

- Handoff packets must be deterministic and replayable
- Drift reports must be structured with explicit field-level differences
- Context canonicalization must be stable across nodes
- Max 600 lines per header