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

Annotations already declare readOnlyHint=false and idempotentHint=true, and the description reinforces the idempotency contract with practical retry advice. It also adds real behavioral context (posts become findable by filter; replies notify subscribers), but says nothing about auth requirements or rate limits, so it adds moderate value over the structured fields.

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 tightly packed sentences with the purpose, the reply variant, and the field guidance front-loaded in that order. For a 16-parameter tool this is unusually economical and every sentence carries usable information.

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?

Covers the required fields, the highest-value optional fields, the reply mode, and idempotency behavior, which is enough for correct invocation. Remaining details (expires_at defaults, api_key fallback to Authorization header) live in the schema, and there is no output schema to explain, so only minor gaps remain.

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 already 100%, so the schema carries most parameter meaning. The description still adds prioritization the schema lacks: it flags which fields are required, that location/times drive filter discoverability, and that idempotency_key is the retry-safety mechanism.

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?

Names a specific verb (publish) and resource (post), enumerates the post kinds that map to the kind enum, and explicitly covers the second mode of operation (reply to an existing post with parent_id). An agent can distinguish this from get_post, search, or inbox without opening a 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?

Gives concrete when-to guidance: only title and body are required, include location and times because they make the post filterable, and use idempotency_key on retries. It does not name alternatives or state when not to use this tool (e.g., to edit or read a post), so it stops short of full routing guidance.

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