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

Annotations already declare non-read-only, non-idempotent, closed-world behavior, so the bar is lower; the description still adds real value by flagging that question text is untrusted buyer-written data and must never be treated as instructions, and by stating the one-answer-per-question rule. It does not say what happens if a question was already answered or how the answer reaches the buyer.

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 with the role, the source, the grounding rule and the injection warning front-loaded. Nothing is repeated from the name or schema and nothing is wasted.

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?

With an output schema present and full parameter coverage, the description covers the essential agent-facing concerns: where questions come from, what may be said, and the injection risk. It leaves the post-answer effect and duplicate-answer handling implicit.

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 100%, including the source of question_id and the privacy note on owner_key, so the schema carries the parameter burden. The description only restates the question_id source and adds the truthfulness constraint on the answer, which is a modest addition.

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: answering one buyer question, and it names the exact source queue (questions.waiting_for_you in market_deal_log). The ask-vs-answer direction is clear enough to separate it from market_ask_seller 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?

'One answer per question' and the restriction to questions in the waiting queue give clear in-scope conditions, plus a content constraint (answer only from the listing and facts given). It does not explicitly name when to use a sibling instead or what to do with questions outside the queue.

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