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

Beyond the readOnlyHint annotation, the description discloses significant behavior: one match credit per wallet returned, empty results are free, retried calls bill again, page size up to 100, and follower-count ordering. This directly informs cost-sensitive agent decisions and is not redundant with the annotations.

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?

The description is compact and front-loaded: purpose first, then cost, edge behavior, and ordering. Every sentence contributes actionable 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?

The tool is moderately complex due to billing and pagination, and the description covers cost, empty results, retries, suffix handling, and ordering. It omits explicit response field details, but with no output schema and a simple wallet-list result, the missing return-shape detail is minor.

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 the schema already documents parameters. The description adds important semantic guidance for the username parameter by warning that stripping .eth will find nothing, which goes beyond the bare pattern and example in the schema.

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 opens with a specific action and resource: 'Find every wallet in the index attested to a Farcaster account.' This clearly distinguishes the tool from sibling 'walletlink_wallets_by_x_handle' by naming the Farcaster domain.

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 clear operational context: pass the username whole, include any .eth suffix, and expect results ordered by follower count. It does not explicitly name sibling alternatives or state when not to use this tool, but the Farcaster-specific scope makes the intended use obvious.

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