post_to_bluesky
Publish a post to Bluesky as the connected account. Text up to 300 characters — Bluesky ALSO caps a post at 3000 UTF-8 bytes, so an emoji-heavy post can be under 300 characters and still be refused; Hermoso checks both before spending the round trip and says which limit and by how much. MEDIA: ei...
This record as markdown: /tools/hermoso/post-to-bluesky.md
What post_to_bluesky does on Hermoso
AI agents use post_to_bluesky to create or update resources in Hermoso, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Hermoso environment.
Why post_to_bluesky is rated Medium
An AI agent can call post_to_bluesky faster than any human can review: one bad instruction and it creates or modifies resources in Hermoso by the hundred, each call as confident as the last.
Attacks that exploit this kind of access
The rule that runs post_to_bluesky safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Hermoso, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For post_to_bluesky, this is the rule to start with:
post_to_bluesky 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 Hermoso, apply this rule, and every post_to_bluesky call is checked against it from then on.
Questions about post_to_bluesky
Publish a post to Bluesky as the connected account. Text up to 300 characters — Bluesky ALSO caps a post at 3000 UTF-8 bytes, so an emoji-heavy post can be under 300 characters and still be refused; Hermoso checks both before spending the round trip and says which limit and by how much. MEDIA: either up to 4 images (imageUrls + altText) OR one MP4 video (videoUrl + videoAlt), never both — a Bluesky post record carries a single embed and images and video are two different embed types. Video is MP4 only, up to 300MB at Bluesky. It is categorised as a Write tool in the Hermoso MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Hermoso MCP server in PolicyLayer and add a rule for post_to_bluesky: 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 Hermoso. Nothing to install.
post_to_bluesky 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 post_to_bluesky 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 post_to_bluesky. 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.
post_to_bluesky is provided by the Hermoso MCP server (https://app.hermoso.ai/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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