mastodon_block_domain
Block a remote domain at the user level (hide all accounts from that domain for the authenticated user). For instance-wide defederation use mastodon_defederate. Rate-limited: 5/hour.
This record as markdown: /tools/kh0pper-crow/mastodon-block-domain.md
What mastodon_block_domain does on Crow
AI agents use mastodon_block_domain 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.
Why mastodon_block_domain is rated Medium
This tool creates a user-level domain block, which modifies the authenticated user's account settings by hiding all accounts from the specified domain. It is reversible (blocks can be undone), so it falls under Write rather than Destructive. Misuse could silently cut off large portions of the fediverse for a user, giving it medium severity.
From the tool's definition Block a remote domain at the user level (hide all accounts from that domain for the authenticated user)
Attacks that exploit this kind of access
The rule that runs mastodon_block_domain 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 mastodon_block_domain, this is the rule to start with:
mastodon_block_domain 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every mastodon_block_domain call is checked against it from then on.
Questions about mastodon_block_domain
Block a remote domain at the user level (hide all accounts from that domain for the authenticated user). For instance-wide defederation use mastodon_defederate. Rate-limited: 5/hour. 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.
Register the Crow MCP server in PolicyLayer and add a rule for mastodon_block_domain: 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.
mastodon_block_domain is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the mastodon_block_domain 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.
Set action: deny in the PolicyLayer policy for mastodon_block_domain. 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.
mastodon_block_domain 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.
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