get_submax_test_trends

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

Annotations give readOnlyHint/openWorldHint, but the description goes well beyond: it quantifies cost (2 API calls plus 2 per power test with check_context), defines the validation rule set that determines what counts as a valid test, discloses the HRRc "not measured is never 0" quirk, and states the output is "statistics only, no verdict." That is rich behavioral context an agent cannot get from the annotations alone.

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 instruction to use it is front-loaded, and each subsequent sentence (validation logic, trending scope, cost, method pointer) adds distinct value. It is dense and parenthetical-heavy, which costs a little readability, but there is no filler.

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?

Ten optional params with no output schema, so the description must carry return semantics, and it does list the returned fields (target, average, CV, end HR, EF, HRRc), the per-sport-family/per-ISO-week trending, plus the detail_level tiers. Coverage is strong; only the exclusion-reason payload and response shape are left partly implicit, keeping it just under a 5.

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% with enums for the two enumerated params, so the parameters are already well documented. The description adds only marginal semantics (default 180-day window, the HRRc caveat, the check_context cost) beyond what the schema states; the 3 baseline is appropriate when the schema carries the load.

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+resource with scope: follow submaximal fatigue tests (SFT) that Intervals.icu detects, over weeks, with the questions it answers (which are valid benchmarks, how HR responds). No sibling tool covers SFT trends, so it is clearly differentiated.

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?

"Use to follow ... over the weeks" gives a clear trigger, and the method pointer (intervals://methods/fatigue via get_guide) tells the agent where the concept is defined. It stops short of naming when-not or an alternative tool, so it is clear context without exclusions.

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