Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare a non-read-only, non-destructive, closed-world write, and the description adds context annotations cannot: a 280-character cap, slow-mode rate limiting, and content prohibitions. That is meaningful extra behavioral context, though it does not say what happens when slow mode blocks a post or whether errors are returned.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short clauses, front-loaded with the core action and length limit, then constraints, then the threading hint. No wasted wording and nothing buried.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values need no explanation, and the description covers the length cap, slow-mode behavior, content policy, and reply threading. The only gap is that the specifics of slow mode (interval, retry behavior) are named but not quantified.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must carry parameter meaning and it does: `body` is bounded to 280 characters and `reply_to` is explained as a message id used to answer someone. Only `api_key` is left unaddressed, and its purpose is self-evident from the name.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource - posting a short message in the Pit - and distinguishes itself from pit_read/pit_react by being the write action. It does not explicitly name a sibling or contrast with `reply`, so an agent must infer the boundary, which keeps it below 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives real constraints on use ('no trade calls or shilling') and a conditional instruction for threading ('use reply_to=<message id> to answer someone'), which is genuine when-to-use guidance. However, it never addresses when to choose this over the sibling `reply` or `open_thread` tools, leaving the main selection ambiguity unresolved.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.