create_manual_activity

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

With no annotations, the description carries the burden of explaining behavior. It does disclose important behavioral constraints: type_key must match a Garmin activity type, default values for start_time, distance_km, activity_name, and time_zone, and how activity_name defaults to type_key. However, it does not mention potential side effects, permission requirements, response behavior, or whether logging creates duplicates.

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 well-structured: a one-line purpose, a short type_key guidance paragraph, and a clean Args list. Every sentence adds value, and the most important usage constraint (type_key must match Garmin activity types) is highlighted early.

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 7 parameters, no annotations, and 0% schema description coverage, the description is remarkably complete: all parameters are explained, formats and defaults are specified, and the agent is directed to a sibling tool for valid values. The presence of an output schema means return-value details are not required 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?

Schema description coverage is 0%, so the detailed Args section fully compensates. It adds meaning beyond raw property names by providing formats (YYYY-MM-DD, HH:MM, IANA time zone), common type_key examples, units for distance_km, and default behavior for optional fields.

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 opens with a clear, specific verb and resource: 'Log a manual activity in Garmin Connect' and explains the intended use case ('activities done without a watch'). This makes it immediately distinguishable from the many read-only sibling tools and workout-upload tools.

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 gives clear context for when to use the tool ('useful for activities done without a watch') and tells the agent to consult get_activity_types for valid type_key values. It does not explicitly state when not to use it or name alternatives, but the intended context is clear enough for an agent to route correctly.

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