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

Adds real context beyond the annotations: the approval_code gate, the human_approval_required outcome, and that a successful call returns the other side's email. Annotations already declare the safety profile (non-readOnly, non-destructive, non-openWorld), so the remaining gap is what happens on repeat calls or partial-state retries — especially relevant since the schema exposes an idempotency_key while idempotentHint is false, a discrepancy the description does not resolve.

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?

Four short sentences, purpose front-loaded, then the blocking prerequisite, then the return value, then the fallback sibling. Every sentence carries information an agent needs and none repeats structured fields.

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 multi-party workflow step with a human-in-the-loop gate, the description covers the trigger, the blocking condition, and the success indicator, and an output schema exists so return shape needn't be spelled out. It stops short of describing what state the deal is in after a partial approval or how a retry interacts with the idempotency_key, which is the main remaining ambiguity.

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 deal_id, owner_key, approval_code and idempotency_key are already documented at the field level. The description reinforces where approval_code comes from and the consequence of not having it, but adds no new syntax, format, or per-parameter meaning beyond the schema, so the 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 and resource: closing the person's side of a deal they already approved, with a clear terminal outcome (both sides approved). It is distinguishable from the read-only market_deal_log it references, though the phrasing 'close the person's side' is somewhat metaphorical and never says outright that the deal is being bound/accepted.

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 explicit preconditions (requires the approval_code the person sees after pressing Approve) and the exact failure path when it is missing (human_approval_required). It also instructs the agent to ask the person for the code and never guess it, and routes to market_deal_log when the other side's status is in question.

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