session_set_claude_id · Claude Code MCP: Risk & Policy

WHAT IT DOES

What session_set_claude_id does on Claude Code

AI agents use session_set_claude_id to create or update resources in Claude Code — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Claude Code environment.

WHY IT NEEDS A POLICY

Why session_set_claude_id needs a policy

The tool creates or updates a session identifier association, which is a write operation that modifies system state (the session registry or lookup table). It is not destructive since the association can be changed or deleted, and it has no immediate side effects on code execution or data deletion.

From the tool's definition Tool description states it will 'Associate a Claude session ID with *name*', which creates or modifies a mapping/association for future session resumption. This is a metadata write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

session_set_claude_id Rate-limited

session_set_claude_id stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "session_set_claude_id": {
      "limits": [
        {
          "counter": "session_set_claude_id_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Claude Code, so you can run agents against it safely.

FAQ

Questions about session_set_claude_id

What does the session_set_claude_id tool do? +

Associate a Claude session ID with *name* for future --resume support. It is categorised as a Write tool in the Claude Code MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on session_set_claude_id? +

Register the Claude Code MCP server in PolicyLayer and add a rule for session_set_claude_id: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Claude Code. Nothing to install.

What risk level is session_set_claude_id? +

session_set_claude_id is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit session_set_claude_id? +

Yes. Add a rate_limit block to the session_set_claude_id rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block session_set_claude_id completely? +

Set action: deny in the PolicyLayer policy for session_set_claude_id. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides session_set_claude_id? +

session_set_claude_id is provided by the Claude Code MCP server (joschi655/claude-code-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.