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

Goes well beyond the annotations: it discloses that a call without confirm_token creates and sends nothing, that the reply is a preview of the exact text plus a token, that the message is irreversible once sent, that it appears to the candidate as coming from the user's company, and that it uses the already-connected employer account. That is precisely the safety and auth context destructiveHint=true leaves unexplained.

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 the action and its scope, then the prerequisite, then the two-call protocol, then the safety warning — a sensible order with no filler. It is dense but every sentence contributes; only the final account sentence could be trimmed for some readers.

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 destructive, open-world mutation with no output schema, the description covers the things an agent actually needs: prerequisites, the confirm handshake, irreversibility, and auth state. The shape of the returned conversation or preview object is not described, but that gap is minor against the otherwise complete behavioral picture.

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%, so the schema already documents all three parameters, including the slug source and the preview/send meaning of confirm_token. The description reinforces the two-call relationship but adds little parameter-level meaning the schema does not already carry; baseline 3 applies.

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+resource ('Start a conversation with a candidate') scoped by talent_slug, and adds the useful nuance that an existing conversation is returned rather than duplicated. It explicitly routes to search_talent for finding the slug, but never contrasts itself with send_message or reply_to_message, which an agent must distinguish for existing threads.

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 an explicit prerequisite workflow (search_talent first, then the slug), an explicit two-call protocol for the first message, and an explicit instruction to show the user the preview and obtain approval before the second call. The condition that selects the confirm_token path versus the plain path is spelled out rather than inferred.

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