health_get_activity

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

With no annotations, the description fully discloses behavior: caching, need for prior health_sync, rate limit, and the calculation of active minutes ('active_minutes = very_active + fairly_active (excludes lightly active)'). It also notes output granularity ('one entry per day').

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?

Although detailed, the description is well-organized: purpose first, then caching behavior, then rate-limit note, then output details. Each sentence adds value without redundancy, making it appropriately sized for the tool's complexity.

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 simple schema (three optional params), the description covers all relevant aspects: param meanings, default behavior, output structure, and a practical limitation (rate limit). No missing information that would prevent correct use.

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 description explains the date formats ('YYYY-MM-DD', 'YYYY-MM', or '30d') and the meaning of 'live' (fetch from API vs cache). It also clarifies the default values and what the output contains, adding significant meaning beyond the bare schema types and defaults.

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: 'Get daily activity summaries (steps, calories, active minutes, distance).' It identifies the resource (activity summaries) and the action (get), distinguishing it from sibling health getters like heart rate or sleep.

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?

It provides explicit usage guidance: 'Returns data from the local cache by default. Use live=True to fetch from the API. Run health_sync first to populate the cache.' Also includes a note about rate limits and daily API call behavior, which helps decide when to use live=True.

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