read_sensor

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

With no annotations provided, the description carries full burden for behavioral disclosure. The word 'Read' implies a non-destructive operation, but no additional traits (auth needs, rate limits, idempotency) are mentioned. While acceptable for a simple read tool, adding more context would improve transparency.

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 extremely concise, with only three sentences including the arg documentation. It front-loads the purpose and provides necessary guidance without any wasted words.

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 single-parameter tool with an output schema, the description adequately explains the input and references list_sensors for discovery. It does not describe the output format, but given the existence of an output schema, this is acceptable. Could mention return type for completeness.

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. It provides concrete examples of sensor_id values ('pv1_voltage', 'battery_soc', 'grid_power') and instructs to use list_sensors for more IDs, adding significant meaning beyond the bare schema definition.

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 states 'Read the current value of a single sensor by its ID', using a specific verb (read) and resource (sensor value). It distinguishes itself from siblings by referencing list_sensors for ID discovery, which contrasts with other read tools like read_setting.

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 explicitly tells the agent to use list_sensors to discover available sensor IDs, providing clear context for when to use this tool. However, it does not explicitly state when not to use it or compare to other get_* tools, which would be helpful but is not critical for a simple read operation.

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