Anchor

Anchor is a requirements delta agent that compares versions of spec and doc content between git refs, detects section-level changes, and classifies impact severity so teams know what matters before a release.

Install

npm install -g @anchorspec/cli

Quick start

# Verify your environment
anchor doctor

# Initialize Anchor in your project
anchor init

# Compare specs between git refs
anchor compare --file docs/spec.md --from main --to HEAD

# Compare an entire spec corpus
anchor compare --corpus docs/specs --from main --to HEAD

MCP integration

Anchor includes a built-in MCP server for use with Claude Code, Claude Desktop, and other agent hosts.

Add to your MCP settings:

{
  "mcpServers": {
    "anchor": {
      "command": "anchor",
      "args": ["mcp"]
    }
  }
}

Or without a global install:

{
  "mcpServers": {
    "anchor": {
      "command": "npx",
      "args": ["@anchorspec/cli", "mcp"]
    }
  }
}

The MCP server exposes these tools: anchor_compare, anchor_compare_corpus, anchor_targets, and anchor_baseline_status.

Commands

Command	Description
compare	Compare a file or corpus between git refs
baseline	Bootstrap a spec corpus from code
init	Initialize Anchor config (.anchor.yaml)
targets	List configured targets
validate	Validate Anchor configuration
doctor	Check environment (Node, git, API key)
mcp	Start MCP server for agent host integration
watch	Watch for spec changes

Configuration

Anchor reads .anchor.yaml in your project root. Run anchor init to generate one, or create it manually:

version: 3
corpus: docs/specs
targets:
  - name: api
    globs: ["src/api/**"]
  - name: frontend
    globs: ["src/components/**"]

License

MIT