# get_co_changes

Find files that frequently change together in git history (temporal coupling). Requires git. Use to discover hidden dependencies between files. For cross-module co-change anomalies use detect_drift instead. Read-only. Returns JSON: { file, coChanges: [{ file, confidence, count }] }.

Agent View of the PolicyLayer registry record for `get_co_changes`. HTML page: https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/get-co-changes

## Facts

- Tool: `get_co_changes`
- Server: Trace (`nikolai-vysotskyi/trace-mcp`) — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp.md
- Homepage: https://github.com/nikolai-vysotskyi/trace-mcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_co_changes",
    "arguments": {}
  }
}
```

## Why get_co_changes is rated Low

This tool retrieves and analyzes historical metadata from git to identify temporal coupling patterns between files. It performs a query operation on existing git data with no capability to modify, delete, or execute code. The severity is low because reading git history poses minimal risk—an agent cannot misuse this to harm systems or data.

From the tool's own definition: "The tool description explicitly states 'Read-only' and the functionality is 'Find files that frequently change together in git history'. It 'Returns JSON' with analysis data and has no side effects."

## Use case

AI agents call get_co_changes to retrieve information from Trace without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Trace:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "get_co_changes": {}
  }
}
```

## Other tools on Trace (190)

- `delete_corpus` — Destructive — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/delete-corpus.md
- `remove_dead_code` — Destructive — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/remove-dead-code.md
- `repair_index` — Destructive — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/repair-index.md
- `call_project_tool` — Execute — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/call-project-tool.md
- `reindex` — Execute — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/reindex.md
- `visualize_graph` — Execute — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/visualize-graph.md
- `analyze_perf` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/analyze-perf.md
- `assess_change_risk` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/assess-change-risk.md
- `audit_config` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/audit-config.md
- `benchmark_project` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/benchmark-project.md
- `check_architecture` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/check-architecture.md
- `check_claudemd_drift` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/check-claudemd-drift.md
- `check_duplication` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/check-duplication.md
- `check_edit_safe` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/check-edit-safe.md
- `check_embedding_drift` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/check-embedding-drift.md
- `check_quality_gates` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/check-quality-gates.md
- `check_rename` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/check-rename.md
- `compare_branches` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/compare-branches.md
- `detect_antipatterns` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/detect-antipatterns.md
- `detect_ast_clones` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/detect-ast-clones.md
- `detect_communities` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/detect-communities.md
- `detect_drift` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/detect-drift.md
- `detect_topic_tunnels` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/detect-topic-tunnels.md
- `diff_graph_snapshots` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/diff-graph-snapshots.md
- `discover_claude_sessions` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/discover-claude-sessions.md
- `discover_hermes_sessions` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/discover-hermes-sessions.md
- `embed_repo` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/embed-repo.md
- `explain_architecture` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/explain-architecture.md
- `explain_symbol` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/explain-symbol.md
- `export_decisions` — Read — https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp/export-decisions.md
- …and 160 more: https://policylayer.com/tools/nikolai-vysotskyi-trace-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=nikolai-vysotskyi-trace-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/nikolai-vysotskyi-trace-mcp