cancel_offer

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

With no annotations, the description carries full behavioral burden and delivers: it discloses the returned unsigned calldata, the invariance that only the bidder can cancel, the need to include sibling hashes for cross-posted offers, and the WETH-release effect. This is rich, non-obvious behavioral context.

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, purposeful sentences; front-loaded with the core purpose, followed by constraints, effects, and alternative. Every sentence earns its place without fluff.

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?

Given no output schema, the description adequately explains the return value (unsigned calldata), prerequisites, and effects. It could slightly improve by explicitly noting how the calldata should be used (e.g., signed and submitted), but for a narrow, well-scoped tool this is nearly complete.

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% with detailed descriptions for all parameters (orderHash source, alsoCancel variant handling, walletAddress match constraint). The tool description adds a bit of narrative context (e.g., 'pass BOTH order hashes...') but largely restates what the schema already documents, so it stays at the baseline for fully covered schemas.

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?

The description uses a specific verb and resource: 'Cancel an active offer you made on an ENS name' and immediately clarifies the output ('Returns unsigned Seaport cancel() calldata'). It also distinguishes this from the sibling cancel_listing tool by naming the alternative.

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?

It clearly states when to use the tool (only by the bidder/offerer), handles the OpenSea cross-post edge case with alsoCancel, and explicitly directs to cancel_listing for listings. This is strong when-to-use and alternative guidance.

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