MCP Migration Compatibility Checker (2025→2026)

A contract migration can appear compatible until a renamed or unsupported field reaches release review. Compare one local 2025-11-25 baseline snapshot with one 2026-07-28 candidate snapshot and receive a deterministic compatibility decision plus five reviewable evidence files. This checker supports only that fixed revision boundary and does not connect to a live MCP server.

The problem

Manually verifying Model Context Protocol (MCP) contract compatibility during the 2025-to-2026 era migration is error-prone. Developers lack a deterministic way to audit breaking changes between local protocol snapshots without risking subjective LLM hallucinations.

What it does

• Performs deterministic comparison between 2025-11-25 and 2026-07-28 MCP snapshots.
• Generates five auditable artifacts including compatibility reports and evidence receipts.
• Enforces a fail-closed gate resulting in PASS, FAIL, or NEED_USER based on migration rules.
• Validates JSON depth, value-node counts, and type-aware canonical semantics.
• Detects breaking changes in tools, prompts, and schema annotations via local execution.

Frameworks & tools

Python, Model Context Protocol (MCP), JSON Schema, SHA-256 integrity hashing.

Why this beats prompting it yourself

Prompting an LLM to "check for compatibility" leads to missed edge cases in JSON schema evolution. This tool uses a rigid, script-based collector that prevents subjective upgrades of FAIL or NEED_USER statuses, ensuring 100% auditability.

Use cases

• Verifying tool and prompt compatibility before upgrading MCP server implementations.
• Generating compliance evidence for internal architectural reviews.
• Debugging malformed JSON schema transitions between protocol revisions.

Known limitations

Only supports the 2025-11-25 to 2026-07-28 revision boundary. Rejects network shares, remote volumes, and Windows UNC paths. Does not perform automatic fixes or tool execution.