read_sensor

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description does not state whether this is a blocking/real-time read, whether it polls or returns cached values, what units the value is in, or what error cases look like (e.g. nonexistent sensor name). For a read operation with no annotation coverage, this is thin.

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 a single efficient sentence with zero waste. It's appropriately brief for a simple one-parameter tool. Could arguably include a bit more behavioral context, but conciseness itself is excellent.

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 (1 param, no output schema, no annotations), but it's still incomplete. There's no mention of return value format, units, whether invalid sensor names produce errors, or how readings relate to the get_all tool that likely returns multiple sensor values. Given the sibling set includes get_all, some differentiation about when to use read_sensor vs get_all would add significant value.

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 100%, so the schema already documents the 'sensor' parameter with examples (temperature, pressure, motor_speed). The description adds no additional parameter semantics beyond what the schema provides. Baseline 3 is appropriate since the schema handles the heavy lifting for the single parameter.

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 states 'Read a sensor value from the PLC' with a specific verb (Read) and resource (sensor value from PLC). It distinguishes from siblings which handle alarms, status, setpoints, and writes. However, it doesn't fully clarify what 'value' entails (e.g. current reading only, not history), though the purpose is fundamentally clear.

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 basic context ('from the PLC') but no explicit guidance on when to use this tool versus siblings like get_status or get_all. No exclusions or alternatives are mentioned. Usage is implied as 'when you need a sensor reading' but no when-not-to-use information is given.

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