get_activity_hr_zones

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

No annotations are provided, so the description carries the full burden. It discloses the return content (time in each zone and each zone's share) but says nothing about permissions, rate limits, or behavior for invalid/missing activity IDs. Adequate for a simple read-by-ID tool, but not rich.

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 tight sentences: the first front-loads the operation and output, the second justifies usage. Every sentence earns its place with no redundancy.

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 single-param read tool with no output schema and full schema coverage, the description gives the agent enough to call it correctly and understand what comes back. Minor gaps are the lack of error/empty-data handling notes, which are low-stakes here.

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% and the single parameter is documented in the schema, including its source ('from get_activities'). The description adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 — time spent in each HR zone for one activity — plus the response shape (per-zone share). The scoping phrase 'during one activity' implicitly separates it from sibling zone/config tools like get_hr_zones. It stops short of explicitly naming the sibling it differs from.

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?

Offers a concrete decision rationale ('Average HR hides distribution — use this to tell an evenly aerobic run from one that swung between too hard and too easy'), which tells the agent when this is the right tool. It does not name specific alternatives or exclusions among the many sibling getters, so it falls short of a 5.

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