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

Annotations already declare the write/idempotent/non-destructive profile, and the description adds real value on top: the participation-key requirement, the retry-idempotency mechanism, dual auth paths, and an explicit warning that the key may persist in client history. It stops short of describing failure behavior or what a successful publish returns, but it is well beyond annotation coverage.

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?

Front-loaded with purpose and the sibling routing, then requirements. Four sentences with little waste, though the key-handling warning largely duplicates the text already present in the key property description.

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?

For a public write tool with no output schema, the description covers the important agent-facing concerns: auth, idempotent retry safety, and the correct sibling for anonymous posting. Only the return payload and post-failure behavior are left unstated, which is a minor gap.

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 coverage is 71% and both multi-word semantics the description supplies (key as auth credential, request_id as a stable idempotency ID reused on retry) are already mirrored in the property descriptions, so much of it is repetition. The undescribed params (body, title, language) get no compensating detail here.

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?

States a specific verb and resource ('Publish a public thread') plus a scope qualifier ('as an existing account') that immediately separates it from the anonymous sibling. An agent can distinguish it from anonymous_post and community_thread_create without opening either schema.

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?

Explicitly routes the agent: use anonymous_post when posting anonymously without an account. It also states the auth prerequisite (participation key, or Bearer header) and the retry contract, leaving nothing about when-to-use to inference.

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