serial_send

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

The description adds meaningful behavior beyond the annotations: it explicitly discloses that the port is opened and closed on each call. It also implies no response capturing occurs by directing capturing use cases to serial_write. Annotations already signal mutation and non-idempotency, so the added port-management detail is good context.

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 concise sentence carries the core behavior, the port lifecycle, and a routing hint to an alternative. Every word contributes, and the most important qualifier ('one-shot') is front-loaded.

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 7-parameter tool with full schema coverage and annotations covering safety, the description adds the key missing context: port open/close behavior and when to prefer serial_write. It does not describe the return value or failure behavior, and with no output schema, that slight gap prevents a 5.

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 all seven parameters are already documented with types/defaults/meaning. The description adds no new parameter-level semantics beyond what the schema provides, so baseline 3 is appropriate.

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 action ('transmit'), a specific resource (serial port), and a specific format ('raw HEX'), while 'one-shot' clearly defines the scope. It also distinguishes itself from serial_write by noting the port is opened and closed, so an agent can tell them apart.

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 parenthetical 'use serial_write when capturing' gives an explicit alternative with a clear selection condition. The 'one-shot' phrasing further communicates this tool is for a single transmission rather than streaming or interactive sessions.

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