// SCAN REPORT

Mermaid Mcp

17 tools. 3 can modify or destroy data without limits.

3 write tools that can modify data. Rate limits recommended.

Last updated: 6 Jun 2026

3 can modify or destroy data

14 read-only

17 tools total

Free to start. No card required.

TOOL MAP

Read (14) Write / Execute (3) Destructive / Financial (0)

CONTEXT-WINDOW COST

3,536 tokens of tool definitions, loaded on every request

1.8% of a 200k context window

333 heaviest tool: create_pr

Full per-tool breakdown → Model it in the token calculator →

WHAT CAN GO WRONG

Write operations (create_issue, create_pr, push_file) modify state. Without rate limits, an agent can make hundreds of changes in seconds — faster than any human can review or revert.

RECOMMENDED RULES

Rate limit write operations

{
  "create_issue": {
    "limits": [
      {
        "counter": "create_issue_per_hour",
        "window": "hour",
        "max": 30,
        "scope": "grant"
      }
    ]
  }
}

Prevents bulk unintended modifications from agents caught in loops.

Cap read operations

{
  "get_diagram_summary": {
    "limits": [
      {
        "counter": "get_diagram_summary_per_minute",
        "window": "minute",
        "max": 60,
        "scope": "grant"
      }
    ]
  }
}

Controls API costs and prevents retry loops from exhausting upstream rate limits.

ALL 17 MERMAID MCP TOOLS

WRITE 3 tools

Write create_issue Write create_pr Write push_file

READ 14 tools

Read get_diagram_summary Read get_diagram_title Read get_issue_comments Read get_mermaid_syntax_document Read get_pull_comments Read list_branches Read list_issues Read list_mermaid_files Read list_pulls Read list_repos Read list_tools Read read_mermaid_file Read search_mermaid_icons Read validate_and_render_mermaid_diagram

FAQ

How do I prevent bulk modifications through Mermaid Mcp? +

The Mermaid Mcp server has 3 write tools including create_issue, create_pr, push_file. Set a rate limit in your policy -- for example, 10 calls per hour prevents an agent from making more than 10 modifications per hour. PolicyLayer enforces this at the gateway, before calls reach Mermaid Mcp.

How many tools does the Mermaid MCP server expose? +

17 tools across 2 categories: Read, Write. 14 are read-only. 3 can modify, create, or delete data.

How do I enforce a policy on Mermaid Mcp? +

Register the Mermaid MCP server in PolicyLayer, apply the suggested rules above (adjust the limits to your use case), and point your AI client at the PolicyLayer proxy URL instead of the server directly. Your agents keep the same tools; PolicyLayer evaluates every call against policy before it executes. Nothing to install, live in minutes.

Enforce policy on every Mermaid Mcp tool call.

Deterministic rules across all 17 Mermaid Mcp tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

SECURE MERMAID MCP →

Free to start. No card required.

4,600+ MCP servers and 31,000+ tools scanned and risk-classified.

Mermaid Mcp

// TOOL MAP

// CONTEXT-WINDOW COST

// WHAT CAN GO WRONG

// RECOMMENDED RULES

// ALL 17 MERMAID MCP TOOLS

// FAQ