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

Annotations declare it is a mutating, destructive, idempotent operation; the description adds genuinely new context: it sends no email, it closes the agreed placement, and the action is reversible via done:false. This clarifies the reversibility of a destructive-hinted tool, which annotations alone do not convey.

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, front-loaded with the core action and scope, followed by the email caveat and the reopen option. No sentence is 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 simple two-parameter, no-output-schema mutation, the description covers what changes, that no email is sent, and how to undo. Adequate and complete; the only minor gap is not naming the sibling closer it overlaps with.

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 100%, so the baseline is 3, but the description adds meaning beyond the schema by explaining the practical intent of done:false ('reopen one marked by mistake') rather than merely restating the boolean.

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 outcome: 'Records that the placement is done: the link is live, or the deal is agreed.' It separates itself from send_reply by noting it sends no email, though it does not explicitly contrast with the closer sibling archive_thread, leaving some ambiguity about which closing tool to pick.

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 workflow rule ('say so to the other party with send_reply first') and a recovery path ('Pass done:false to reopen one marked by mistake'). Clear when-to-use context, but no statement of when not to use it versus archive_thread or redirect_thread.

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