Read sensors

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real value by enumerating what each sensor entry carries (position, angle, range, unit) and by scoping to enabled sensors, which signals disabled ones are omitted. It does not say whether readings are cached or when they are sampled.

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?

One sentence, front-loaded with the resource and scope, then the return fields. Nothing to trim.

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?

With no input parameters and no output schema, the description carries the return-value burden and does so by listing the fields returned. Missing only edge behavior – what comes back with zero enabled sensors, ordering of entries, or whether a timestamp accompanies 'fresh'.

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 tool takes zero parameters, so the baseline is 4. No syntax or format clarification is possible or needed; the description does not waste space restating an empty 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?

States a specific verb-resource pair ('read_sensors' → 'fresh readings from all enabled sensors') and tells the agent the payload includes mounting position, angle, range and unit. It never names a sibling, so the agent must infer the split from list_sensors/update_sensor, which keeps it out of the 5 tier.

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?

'Fresh readings from all enabled sensors' implies the use case (get current sensor values) and the scope (enabled only), but there is no explicit when-to-use, no exclusion, and no pointer to list_sensors for metadata-only lookups. Usage is inferable rather than stated.

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