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

Annotations declare destructiveHint=true and openWorldHint=true, and the description adds concrete consequences beyond them: the handshake is cancelled, both listings remain listed, and the counterparty is notified. It also discloses the failure conditions (post-confirmation, fee paid) and the user-confirmation requirement, which is exactly the extra context annotations cannot carry.

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, front-loaded with the trigger condition, then consequences, then blockers, then the safety step. No filler or repetition.

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, return values need no explanation. The description covers trigger, side effects, failure modes and required user confirmation, which is everything an agent needs to call this destructive mutation correctly.

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?

Only one parameter (handshake_id) and schema description coverage is 100%, so the schema already fully documents it. The description adds no format, sourcing, or lookup guidance for the ID, 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 ('call off a trade') plus the scope constraint ('that hasn't been confirmed by both sides yet'), which cleanly separates it from confirm_handshake, complete_handshake and withdraw_proposal in the sibling list.

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 trigger conditions ('when the user wants to call off a trade') and explicit exclusions ('not possible once both sides have confirmed or if a fee has been paid'), plus a procedural requirement to confirm with the user first. Nothing about when to invoke is left to inference.

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