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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the bar is lower, yet the description adds substantial context: who may invoke it, that multiple bidders are notified individually, that in-progress cancellation returns 95% of the held amount with 5% retained, and that the $2 posting fee is not refunded. These are precisely the side effects an agent needs to reason about.

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 sentences, front-loaded with the action and state rules, followed by reason requirements and then financial/notification effects. Every sentence carries distinct operational information with 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 destructive, multi-party cancellation with financial consequences and no output schema, the description covers permissions, required inputs, notifications, and refund handling. An agent has enough to decide whether and how to call it.

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 both parameters are already documented, but the description adds nuance beyond the schema by spelling out the exact conditions under which 'reason' becomes mandatory: whenever the job is in progress, or open with one or more bids. That conditional logic is more precise than the schema's simpler 'Required unless the job is open with no bids'.

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?

Starts with a specific verb and resource ('Cancel a job') and immediately qualifies the states in which cancellation is permitted. It does not name or distinguish itself from any sibling tool such as request_close, so it falls short of full sibling differentiation.

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?

The description gives explicit state-based permission rules: open jobs can only be cancelled by the buyer, in-progress jobs by the buyer or accepted bidder. It also states when a reason is required versus optional, but does not name an alternative tool for related actions like closing or requesting closure.

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