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

The description adds significant behavioral context beyond annotations: it explains the aggregation mechanism ('People near the same gym on the same plan count together') and the side effect ('when enough do, btw asks for a group rate'). This is valuable behavior disclosure that annotations (readOnlyHint false, idempotentHint true) do not cover. No contradiction.

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 two concise sentences that front-load the purpose, then list the parameters, then state the behavioral nuance. There is no filler or redundancy; every clause contributes to understanding.

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 tool with 4 simple parameters, no output schema, and clear annotations, the description covers purpose, parameters, and the key aggregation behavior. It could optionally mention what happens after the want is recorded, but that is likely covered by the overall btw flow. Overall it is complete enough 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?

Schema description coverage is 100%, and the description essentially restates the parameters (name, five-digit zip, plan enum, email). It adds no new meaning beyond what the schema already provides, such as format, constraints, or purpose. The baseline of 3 is appropriate since the schema carries the semantic load.

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 clearly states the tool records a desire for a gym or studio membership: 'Your human wants a membership at a gym or studio near them.' It names the specific resource type and lists the key parameters, making it easily distinguishable from siblings like want_home, want_software, and want_stay.

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 makes it obvious when to use this tool: whenever the want is for a gym or studio. It does not explicitly mention alternatives, but the contrast with sibling tools is implicitly clear from the specific resource type. No exclusions or competing conditions are stated, but the scope is unambiguous.

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