get_metrics_catalog

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly indicates this is a read operation ('Get'), but doesn't specify whether authentication is required, rate limits, error conditions, or what format the catalog returns. While adequate for a simple catalog tool, it lacks details about behavioral traits beyond the basic operation.

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, well-structured sentence that efficiently communicates the tool's purpose, resource, and usage context. Every word earns its place, with no wasted text or redundancy. It's front-loaded with the core purpose and provides necessary context in a compact form.

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 tool has 0 parameters, 100% schema coverage, and an output schema exists, the description is reasonably complete. It explains what the tool does and when to use it, though it could benefit from mentioning what the catalog contains (metric definitions, types, etc.) or how the output is structured. The existence of an output schema reduces the need to describe return values in the description.

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 0 parameters with 100% schema description coverage, so the baseline for no parameters is 4. The description appropriately doesn't discuss parameters since none exist, and instead focuses on the tool's purpose and usage context, which is the correct approach for a parameterless 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 clearly states the tool's purpose with a specific verb ('Get') and resource ('catalog of available metrics'), and explicitly distinguishes it from sibling tools by mentioning which specific tools the metrics can be used with (metric_time_series and metric_samples). This provides clear differentiation from other siblings like get_location_time_series or get_workouts.

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 explicitly states when to use this tool: to get metrics that can be used in time-series API calls, and specifically names the two sibling tools (metric_time_series and metric_samples) where these metrics are applicable. This provides clear guidance on usage context and distinguishes it from alternatives.

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