matrix_register_appservice

SERVERCrow SOURCEkh0pper/crow

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/kh0pper-crow/matrix-register-appservice.md

WHAT IT DOES

What matrix_register_appservice does on Crow

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

RISK

Why matrix_register_appservice is rated Medium

This tool writes configuration (registration YAML) into a Matrix homeserver (Dendrite), creating a new appservice registration. It is a Write operation since it creates/modifies server configuration.

From the tool's definition Register a Matrix appservice... Writes the registration YAML into Dendrite

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs matrix_register_appservice safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Crow, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For matrix_register_appservice, this is the rule to start with:

matrix_register_appservice Rate-limited

matrix_register_appservice 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": {
    "matrix_register_appservice": {
      "limits": [
        {
          "counter": "matrix_register_appservice_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every matrix_register_appservice call is checked against it from then on.

FAQ

Questions about matrix_register_appservice

What does the matrix_register_appservice tool do? +

Register a Matrix appservice (used by F.12 matrix-bridges bundle). Writes the registration YAML into Dendrite. It is categorised as a Write tool in the Crow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on matrix_register_appservice? +

Register the Crow MCP server in PolicyLayer and add a rule for matrix_register_appservice: 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 Crow. Nothing to install.

What risk level is matrix_register_appservice? +

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

Can I rate-limit matrix_register_appservice? +

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

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

matrix_register_appservice is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Crow, and thousands of servers like it.

This server

All 587 Crow tools →

Across the catalogue

team_manager_register_agents on Team Manager MCP → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →