AI agents use create-post to create or update resources in Bluesky — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Bluesky environment.
This tool creates new data (posts) on the Bluesky social network. Creation is reversible (posts can be deleted via the sibling 'delete-post' tool), making it a Write action rather than Destructive. Severity is medium because an AI agent misusing this could post misleading content, spam, or impersonation at scale, but the impact is limited to the authenticated user's account and can be remediated by deletion.
From the tool's definition Tool name 'create-post' and description 'Create a new post on Bluesky' explicitly indicate creation of new content. Server description confirms it 'can post on your behalf by using the AT Protocol.'
Documented attack patterns abuse exactly the kind of access create-post gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Bluesky, and nothing reaches the server without passing your rules. This is the rule we recommend for create-post:
{
"version": "1",
"default": "deny",
"tools": {
"create-post": {
"limits": [
{
"counter": "create-post_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create-post 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.
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Create a new post on Bluesky. It is categorised as a Write tool in the Bluesky MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Bluesky MCP server in PolicyLayer and add a rule for create-post: 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 Bluesky. Nothing to install.
create-post 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 create-post 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 create-post. 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.
create-post is provided by the Bluesky MCP server (semioz/bluesky-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Bluesky, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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11 Bluesky tools catalogued and risk-classified — across an index of 43,000+ MCP servers.