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

Annotations already declare readOnly/idempotent/non-open-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: executive-branch filers return null with an explanation and identifiers are never invented, which sets expectations for partial results. It stops short of rate limits or pagination, so not a 5.

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 tight sentences, front-loaded with the core behavior and edge case, then filtering modes, then the recommended resolution sequence. Every sentence carries distinct information with no redundancy.

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?

An output schema exists and the annotations are rich, so return formatting and safety need not be repeated. For a 3-param, 0-required lookup tool, the purpose, edge-case null behavior, filtering semantics, and resolution workflow are all present.

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 parameter meaning is already fully documented (substring name, Bioguide example, exact member_id). The description largely restates the same semantics plus a resolution order, adding little that isn't already in the schema; 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 action (list filers with official identity) and clearly scopes the population (congressional filers carry Bioguide IDs; executive-branch filers return null). An agent understands what it returns. It does not differentiate from siblings, though none of the listed siblings genuinely overlap, so a 4 rather than 5.

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 an explicit resolution workflow: 'Resolve a person with name first, then confirm with the returned member_id or bioguide,' and enumerates the three filtering modes. It provides clear context but does not state when to prefer this over an alternative tool, nor any exclusions.

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