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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, covering the safety profile. The description adds value by enumerating the specific metrics returned (active members, plans, revenue, check-ins), but it does not disclose important behavioral details such as the time range for revenue, permissions required, or response format.

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 a single, front-loaded sentence that lists the key indicators without any filler. It is appropriately sized for a simple reporting tool, though it could be slightly more structured (e.g., using a bullet list for readability).

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?

Given the absence of an output schema, the description must convey the return values. It lists the indicators but omits critical details like the aggregation period (e.g., current month vs. all-time) and the response structure. For a reporting tool, this leaves some ambiguity about what the agent will actually receive.

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 takes no parameters, so parameter semantics are minimal. The description does not need to explain parameters, and the baseline score of 4 is appropriate for a zero-parameter tool.

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 the tool returns specific gym indicators: active members, plans with access, revenue per month, and check-ins at the door. This clearly defines the resource and scope, but it does not differentiate this tool from similar siblings like get_financial_metrics or get_checkins_overview.

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 provides no guidance on when to use this tool versus alternatives. It does not mention any context, prerequisites, or exclusions, leaving the agent to infer usage from the name and listed indicators alone.

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