query_fit_activities

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

With no annotations, the description carries the full burden and does add genuinely non-obvious behavior: the call succeeds with a clean 'not available' result and never errors. That prevents an agent from misreading a placeholder as real data. It still omits auth requirements, what an invalid field returns, and how resolution affects output.

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?

Two short sentences, zero filler. The core purpose leads and the availability caveat, which is the single most decision-relevant fact, follows immediately.

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 low-complexity, 4-parameter query tool with no output schema, the description adequately covers the behavioural quirk but leaves parameter formats (field naming, resolution values, date format) undocumented in both schema and text. An agent could call it successfully but not interpret the arguments well.

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 schema documents nothing and the description must compensate. It covers the 'field' and date-range parameters implicitly but says nothing about 'resolution' (default 'daily'), its allowed values, or the expected date format, leaving the coverage gap half-filled.

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 states a specific verb and resource ('Query FIT activity data for a field over a date range'), which is concrete and distinct from sibling names like query_health or query_raw. It does not explicitly contrast itself with those siblings, so it loses the top tier, but the purpose is unambiguous.

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 discloses an important negative condition — the tool is not yet functional (FIT pipeline v1.8) and returns a placeholder rather than an error. However, it never names an alternative (e.g., query_raw) for an agent that actually needs this data now, so routing guidance is implied rather than explicit.

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