get_power_histogram

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

With no annotations provided, the description carries the full behavioral burden. It explains how the tool works ('Analyzes how power was distributed across the activity, showing time spent at different power levels') and what it returns ('JSON string with power distribution bins'). This goes beyond a simple one-liner, though it omits potential edge cases like missing power data or permissions.

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 well-structured with a one-sentence summary, a short use-case paragraph, and clearly labeled Args/Returns sections. It is front-loaded with the main purpose and contains no filler. The slight redundancy between the first line and the second paragraph is minor and does not detract from overall clarity.

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 simple read-only tool with one parameter, the description is complete: it states the purpose, explains the analysis, identifies a use case, defines the only parameter, and specifies the return format. Since an output schema is present, the description does not need to enumerate bins. No critical context is missing.

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 schema already provides 100% coverage for activity_id with a clear description. The Args section essentially repeats the schema ('activity_id: The unique ID of the activity') without adding format details, constraints, or examples. This meets the baseline of 3 but does not exceed it.

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 opens with a specific verb+resource: 'Get power distribution histogram for an activity.' It clearly distinguishes from siblings like get_hr_histogram and get_pace_histogram by naming 'power' explicitly, and the phrase 'power distribution histogram' uniquely identifies the tool's purpose.

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?

The description provides clear use-case context: 'Useful for understanding workout intensity distribution and identifying training zones.' However, it does not explicitly contrast with alternative histogram tools (e.g., get_hr_histogram, get_pace_histogram) or mention when not to use this tool, so it stops short of the highest bar for usage guidance.

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