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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds value beyond annotations by specifying that cancelled signups are excluded, the data scope (active signups at the user's school), and the dependency on cancellation. No contradiction with 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?

Four short sentences, each carrying distinct information: safety, return content, exclusion filter, and downstream usage. No filler, and the most critical information (read-only, what it returns) is front-loaded.

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 no-parameter tool with an output schema present, the description covers all necessary operational details: return fields, scope, exclusions, and the relationship to cancellation. Nothing critical is missing for an agent to call it correctly.

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?

The tool has zero parameters, so the input schema is empty and coverage is effectively 100%. The description appropriately doesn't dwell on parameters; the baseline for 0-param tools is 4, and no additional parameter explanation is needed.

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 states a specific verb ('Returns') and resource ('volunteer signups'), with explicit fields returned. It distinguishes from siblings like list_my_event_registrations (different resource) and cancel_my_volunteer_signup (different action). The scope is clear: authenticated user's active signups at their school.

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 mentions that returned IDs are required by cancel_my_volunteer_signup, which gives a concrete use case and implies this tool is the precursor for cancellation. However, it doesn't explicitly contrast with other list tools (e.g., list_my_event_registrations) or state when not to use it, leaving some inference to the agent.

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