evidence-diff-mcp

Evidence Diff is a local MCP tool for explaining coarse changes in a Git project’s test and build evidence. It can tell an agent that a worktree changed, that uncommitted evidence exists, or that test-like artifacts appear without build-like artifacts, without exposing source diffs.

Tool

• explain_change_evidence: inspect local Git state and bounded top-level evidence names.

Safety

• Local paths only, bounded by EVIDENCE_DIFF_ROOT and realpath checks.
• Returns only counts, coarse categories, coarse branch state, and commit dates.
• Never returns source diffs, evidence filenames, branch names, file paths from Git output, commit subjects, authors, command output, file contents, or secrets.
• Does not execute tests, builds, or arbitrary project commands.
• This is an evidence explanation aid, not a code review or CI oracle.

Run

npm install
npm run build
node dist/index.js

Quick start

npm install
npm run build
node dist/index.js

The server uses stdio, so it can be connected to Claude Desktop, Cursor, VS Code, MCP Inspector, or another compatible MCP client.

Tools at a glance

• explain_change_evidence: Explain coarse changes in local Git and test-build evidence without returning source diffs, file contents, or secrets.

Try it

After building, connect the server through your MCP client. The repository root also contains smoke-test.mjs for projects covered by the shared harness. A typical tool call starts with explain_change_evidence.

Premium tools

These tools need a licence key:

• public_revision_evidence
• public_check_evidence

The tool bodies run on our gateway, not inside this package, so the key is what buys access. Buy one at https://buy.polar.sh/polar_cl_mrO7rS5LZxpqM7oAFFEA10i9121J240U40IIj4JRZO4 and set it in your MCP client config:

"env": { "MCP_LICENSE_KEY": "polar_..." }

The gateway checks the key against Polar and gives every key 1,000 free premium calls a month before per-call billing starts. Every other tool on this server stays free.