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

Annotations already declare readOnlyHint=false and idempotentHint=true, so the description is not carrying the safety burden alone. It still adds real behavioral context beyond them by stating 'Ledger keeps the record; nothing is deleted' — clarifying that this cancel is a soft state change, not data destruction. It does not cover permissions or what the response returns.

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, then the conditions, then the ledger guarantee — no wasted sentences. The trailing empty-braces example is terse to the point of ambiguity given that no parameter is marked required.

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 three-parameter, fully schema-documented tool with no output schema, the description supplies the missing pieces: when to invoke it and what happens to the underlying record. Nothing essential to calling it correctly is absent.

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 key, reason, and listing_id are already documented in the schema; the baseline of 3 applies. The description adds no meaning about listing_id scoping or reason handling, and the example 'barter_cancel {}' shows an empty argument set, which does not clarify how the target listing is identified.

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 ('Cancel listing') that an agent can map directly to the operation. It does not explicitly contrast with the similarly named bazaar_cancel_listing sibling, so it stops 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 'WHEN:' clause gives two concrete triggering conditions: withdrawing an open listing, or an agreed deal whose house cut is unpaid. It does not name an alternative tool or state when-not to use this, but the positive conditions are clear enough to act on.

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