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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful operational context beyond that: per-call span caps (7 days for raw, 92 days for hourly), the 31/366-day history bounds, UTC time handling, and that daily means include a per-day quality check.

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?

It is front-loaded with the core operation and packed into a single dense sentence followed by defaults and a time-zone note. Every clause carries information, though the interval parenthetical is somewhat crammed and could be more scannable.

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 4-param read-only tool with no output schema, the description covers intervals, window limits, defaults and timezone well. The main omission is what happens if the requested range exceeds a call's maximum span (error vs. truncation), which an agent would need to know to call it correctly.

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?

At 50% schema coverage, the description meaningfully compensates: it explains what each interval enum value returns (raw, 5-minute means, hourly means, daily means with quality check) beyond the bare enum labels. It does not clarify error behavior for from/to ranges exceeding the caps, but the key semantics are added.

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 names a specific verb (readings of one sensor) and enumerates the four interval types with their windows, so the agent knows exactly what data comes back. It does not explicitly differentiate itself from siblings like get_sensors_average or get_air_quality_history, which keeps it from a 5.

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?

Defaults are stated (last 24 hours, or 30 days by day) and per-interval window limits are given, which implies when each interval is appropriate. However, there is no explicit statement of when to choose this tool over siblings such as get_sensors_average or get_air_quality_history, leaving the routing decision to inference.

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