get_best_effort_chart

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

With no annotations provided, the description carries the behavioral disclosure burden. It discloses that the return value is a PNG, that the chart is log-scaled, and that it aligns with the sibling's `kind` semantics. It does not explicitly state read-only or describe edge-case behavior, but for a chart-retrieval tool the disclosed format and scaling are meaningful behavioral context beyond the bare schema.

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 about 50 words, front-loaded with the core definition and immediately followed by the use-case and alternative routing. Every sentence earns its place; there is no fluff or repetition of schema fields.

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?

The tool has 4 parameters, no output schema, and no annotations, so the description is the sole source for call semantics. It provides clear purpose and usage, but does not explain the date-range parameters (`newest`, `oldest`) or `sport_type` filtering, and gives no details about how the PNG is returned. This is adequate for a first approximation but incomplete for reliable invocation.

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 description must compensate for all four parameters. It only explains `kind` (hr, pace, power) and mentions duration/distance as chart axes, not parameter meanings. The `newest`, `oldest`, and `sport_type` parameters are left entirely undocumented, leaving the agent to infer their roles from defaults or sibling tools.

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 defines the output as 'A PNG of the best-effort curve' and specifies the plotted variables (HR, pace, power vs duration/distance) plus the log-scaled x-axis. It also distinguishes itself from the sibling get_best_efforts by contrasting the full curve with 'ten named points', giving an agent a precise sense of what this tool produces.

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 explicitly states when to use this tool: 'Use this when the shape of the curve -- a plateau, a cliff past some duration -- says more than the ten named points get_best_efforts returns.' This names the alternative tool directly and provides a clear decision rule, so an agent can route correctly.

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