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

Annotations already flag a non-read-only, destructive, open-world write, but the description adds a genuinely useful fact not in the annotations: the reply is posted publicly from the connected account and should be user-confirmed first. It does not cover rate limits, edit/delete of the posted reply, or failure modes beyond what the idempotencyKey schema field explains.

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 sentences, each earning its place: the action, the public-posting risk with a confirmation directive, and the read-first/language prerequisite. Front-loaded with the core action and no filler.

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 3-parameter public write with no output schema, the description covers the key operational concerns: where the mention id comes from, that the post is public, user confirmation, and language matching, with retry semantics handled by the idempotencyKey schema. It leaves the success/response shape and any rate or permission constraints unstated, but nothing critical to calling it correctly is missing.

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 67%: mentionId and idempotencyKey are documented in the schema, while 'text' has no description. The description partially compensates for 'text' by implying language matching ('match its language') but adds no format, length, or content constraints beyond that. Mid-range coverage keeps this at a baseline 3.

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?

Specific verb+resource ('Reply ... to a mention') with an added qualifier that the mention comes from a saved search, which helps separate it from the many other reply tools. It does not explicitly name the nearest siblings (reply_to_comment, reply_to_review, reply_booking_review), so the agent must infer the distinction from the mention/saved-search framing and the schema's 'Id from list_mentions' hint.

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 real procedural context: read the mention first, match its language, and confirm the text with the user before posting. However, it never states when to choose this tool over reply_to_comment or reply_to_review, and gives no exclusions or prerequisites about account/network availability.

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