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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description goes beyond them, disclosing return structure ('one row per participant, in slot order', email empty when absent, Q&A pairs for custom questions) and the auth requirement. This is useful added context not present in 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?

Front-loaded with the core purpose and return shape, then parameter guidance and the auth note. Mostly efficient, though the sentence order mixes output details with usage guidance.

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 no output schema, the description carries the return-value burden and does so adequately (fields returned, row ordering, empty-email case). The auth requirement is noted. Minor gap: no explicit pagination or result-limit behavior mentioned.

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 all three parameters. The description's 'use from and to to limit the slot dates' essentially restates the schema's own parameter descriptions without adding format or edge-case detail, so 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+resource: 'Who signed up for which slot' clearly identifies it as a participant-list operation. This distinguishes it from sibling list_signups (which lists sign-ups) and get_signup (which fetches a sign-up).

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 clear context: 'Use from and to to limit the slot dates' and states the signup_id source ('from list_signups'). It notes the API key requirement. However, it does not explicitly name alternatives or when-not to use this versus get_signup or list_signups.

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