create_manual_activity

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

With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Log' and lists input constraints; it does not mention side effects, permissions, reversibility, validation failures, or whether it overwrites anything. For a write operation this is a significant gap.

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 front-loaded with the purpose, followed by a useful type_key note and a compact Args list. It repeats a few defaults already in the schema, but the extra format details earn their place. No filler or fluff.

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 7-parameter write tool with no annotations, the description covers the parameter space well and directs agents to the right reference for valid type_key values. It avoids explaining return values because an output schema exists. Missing error-handling details, but the essentials are present.

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%, but the description compensates thoroughly: it documents every parameter with formats (YYYY-MM-DD, HH:MM), defaults (09:00, UTC, 0.0, default to type_key), and a meaningful controlled vocabulary for type_key, including a pointer to get_activity_types. This adds exactly the meaning the schema lacks.

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?

States a specific verb and resource: 'Log a manual activity in Garmin Connect'. The phrase 'manual activity' and 'without a watch' distinguishes it from workout-creation and upload tools like create_strength_workout or upload_workout. Clear intent, no ambiguity.

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?

Explicitly gives the primary use case ('useful for activities done without a watch') and instructs the agent to use get_activity_types for valid type_key values. It does not explicitly name alternatives or exclusions, but the context is sufficient for tool routing.

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