get_activity

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

With no annotations, the description carries the full burden. It discloses that the activity must be 'completed' and that data includes 'per-rep actuals — watts, heart rate, cadence per detected interval.' However, it does not describe error behavior, permissions, or other side effects. It adds some behavioral context but lacks depth expected for an unannotated tool.

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 short sentences, front-loaded with the core action. The second sentence provides purpose and a usage hint. No filler or redundancy; every word earns its place.

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 simple one-parameter fetch tool with an output schema, the description is fairly complete. It explains the resource, the data contained, and the prerequisite workflow. It does not discuss edge cases or permission requirements, but the presence of an output schema reduces the need to explain return values.

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%: the activity_id parameter is fully described with an example and a reference to review_period. The description reinforces this by mentioning review_period, but it does not add new meaning beyond the schema. Baseline 3 is appropriate.

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 action: 'Fetches one completed activity with its intervals.' This is a specific verb (fetches) with a specific resource (one completed activity) and a specific scope (with intervals). It distinguishes the tool from siblings like review_period by focusing on a single activity's interval data.

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 explicit usage context: 'Run review_period first to find the activity id.' This instructs the agent on a prerequisite and references a sibling tool. It also states the intended use case ('for checking how a structured workout actually went'), giving clear context for when to use this tool, though it does not explicitly mention when not to use alternatives.

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