dialogue_post_message · Claude Dialogue MCP: Risk & Policy

WHAT IT DOES

What dialogue_post_message does on Claude Dialogue MCP

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

WHY IT NEEDS A POLICY

Why dialogue_post_message needs a policy

Posting a message is a reversible write operation that creates data in a shared notebook. While not destructive, it modifies thread state persistently. Severity is medium because malicious use could involve impersonation (posting false messages as another Claude instance) or flooding threads, but the blast radius is limited to asynchronous dialogue coordination and the impact is reversible (messages can presumably…

From the tool's definition Tool description states 'Post a message to a dialogue thread' — this creates new data (messages) in a persistent thread structure. The ability to post as either 'claude_app' or 'claude_code' indicates identity assumption capabilities.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

dialogue_post_message Rate-limited

dialogue_post_message 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": {
    "dialogue_post_message": {
      "limits": [
        {
          "counter": "dialogue_post_message_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 Dialogue MCP, so you can run agents against it safely.

FAQ

Questions about dialogue_post_message

What does the dialogue_post_message tool do? +

Post a message to a dialogue thread as either claude_app or claude_code. This is the core communication primitive. Each instance self-identifies via the. It is categorised as a Write tool in the Claude Dialogue MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on dialogue_post_message? +

Register the Claude Dialogue MCP server in PolicyLayer and add a rule for dialogue_post_message: 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 Dialogue MCP. Nothing to install.

What risk level is dialogue_post_message? +

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

Can I rate-limit dialogue_post_message? +

Yes. Add a rate_limit block to the dialogue_post_message 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 dialogue_post_message completely? +

Set action: deny in the PolicyLayer policy for dialogue_post_message. 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 dialogue_post_message? +

dialogue_post_message is provided by the Claude Dialogue MCP server (themethodolojeeorg/claude-dialogue-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.