send_sub_device_command

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

With no annotations, the description carries the full burden, and it does disclose real behavioral traits: the command is not validated against a catalog and is relayed opaquely for the master/sub-device to interpret. That tells the agent errors won't be caught here and gives a mental model of the relay path. It omits failure/timeout behavior and side-effect characteristics, keeping it short of 5.

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 core purpose and kept to two tight sentences with no filler. The second sentence is a slightly run-on triple clause, but every clause carries information an agent needs about the unvalidated relay.

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 an opaque, unvalidated mutation-style command with no annotations and no output schema, the description covers what the tool does and its non-validating nature, but leaves open what the agent should expect on failure, whether the device acknowledges/returns anything, and any auth or reachability requirements. Adequate but with clear gaps for this complexity.

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 cmd, params, deviceId, and subDeviceId are already documented (including the 'only if paramsSchema is declared' nuance for params). The description adds no extra parameter meaning, so the baseline 3 applies.

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?

Specific verb (send) plus resource (command to a specific sub-device behind a master) and an explicit scope contrast: 'instead of the master itself.' This lets an agent distinguish it from the sibling send_command (which targets the master) without reading either 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?

The phrase 'instead of the master itself' implicitly routes the agent here when the target is a sub-device rather than the master, which is meaningful selection guidance. It stops short of naming send_command as the alternative or stating preconditions (e.g., that the sub-device must be reachable), so it is clear context but not full when/when-not guidance.

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