# run_cypher

A execute tool on the Mcpg MCP server.

Agent View of the PolicyLayer registry record for `run_cypher`. HTML page: https://policylayer.com/tools/io-github-devopam-mcpg/run-cypher

## Facts

- Tool: `run_cypher`
- Server: Mcpg (`pypi:mcpg`) — https://policylayer.com/tools/io-github-devopam-mcpg.md
- Install: `npx -y pypi:mcpg`
- Homepage: https://github.com/devopam/MCPg
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

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

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

## Why run_cypher is rated High

Despite the empty description, the tool name 'run_cypher' indicates code/query execution capability. This falls under Execute rather than Read because Cypher queries can perform writes, deletes, and complex operations beyond simple retrieval. Severity is high due to potential for data modification or unauthorized access in a production PostgreSQL environment.

From the tool's own definition: "Tool named 'run_cypher' with empty description on PostgreSQL MCP server. Cypher is a query language for graph databases (Neo4j)."

## Use case

AI agents invoke run_cypher to trigger actions in Mcpg. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

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

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "run_cypher": {
      "limits": [
        {
          "counter": "run_cypher_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Mcpg (251)

- `cancel_migration` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/cancel-migration.md
- `drop_graph` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-graph.md
- `drop_property_graph` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-property-graph.md
- `drop_publication` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-publication.md
- `drop_subscription` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-subscription.md
- `dump_database` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/dump-database.md
- `partman_drop_partition` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/partman-drop-partition.md
- `prune_audit_events` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/prune-audit-events.md
- `restore_database` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/restore-database.md
- `cancel_query` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/cancel-query.md
- `cluster_vectors` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/cluster-vectors.md
- `complete_migration` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/complete-migration.md
- `dry_run_ddl` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/dry-run-ddl.md
- `enable_extension` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/enable-extension.md
- `enable_logical_replication_on_demand` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/enable-logical-replication-on-demand.md
- `enable_redis_fdw` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/enable-redis-fdw.md
- `generate_graph_projection` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/generate-graph-projection.md
- `generate_test_data` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/generate-test-data.md
- `hybrid_search` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/hybrid-search.md
- `maintain_turboquant_index` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/maintain-turboquant-index.md
- `mmr_search` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/mmr-search.md
- `open_cursor` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/open-cursor.md
- `optimize_query` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/optimize-query.md
- `partman_run_maintenance` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/partman-run-maintenance.md
- `pg_search_run` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/pg-search-run.md
- `prepare_migration` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/prepare-migration.md
- `prewarm_recommended` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/prewarm-recommended.md
- `prewarm_relation` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/prewarm-relation.md
- `recommend_redistribute` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/recommend-redistribute.md
- `reindex_pg_search_index` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/reindex-pg-search-index.md
- …and 221 more: https://policylayer.com/tools/io-github-devopam-mcpg.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=io-github-devopam-mcpg · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-devopam-mcpg