get_body_battery_range

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

With no annotations, the description carries the burden, and it does disclose meaningful traits: the raw per-timestamp arrays are discarded in favor of daily summaries, and the `daily` array is newest-first. It stops short of stating read-only/no-side-effects explicitly, relying on the 'get' naming to convey that.

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?

Front-loaded with the payload shape, then the sibling contrast, then the two behavioral notes. The 'large and rarely useful' rationale for summarization earns its place by preventing an agent from hunting for raw data.

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 is simple (one optional param, output schema present), so the description needn't explain return values. It covers the purpose, alternative, and array ordering; the only gap is the absence of an explicit safety profile given no annotations exist.

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 coverage is 100% and the single `days` parameter is fully documented in the schema (range 1-30, default 7). The description adds nothing about the lookback window, so it sits at the baseline for a fully-documented schema.

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 first line names the resource (body battery), its scope (daily range), and the exact metrics returned (charged, drained, highest, lowest, end of day). The second sentence explicitly contrasts it with the sibling get_recovery, so an agent can distinguish the two without inspecting the schema.

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 names the alternative (get_recovery) and the condition that selects it: get_recovery gives only today's levels, while this tool is for history/trends. The routing decision is fully specified with no inference required.

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