write_line

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

With no annotations, the description carries the full burden. It does disclose two useful behaviors — a newline is appended, and the port must already be open — but says nothing about whether the write blocks, what happens if the port is closed, whether output is buffered, or how errors surface.

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?

A single front-loaded sentence with the verb first and the example trailing; nothing is wasted and the agent gets the core behavior immediately.

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?

An output schema exists, so return values need not be explained. However, for a write tool with zero annotation coverage and zero schema description coverage, the definition omits the port identifier convention and failure behavior that an agent would need to call it reliably.

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% across three parameters, so the description must compensate and largely does not. It clarifies that 'text' is combined with a newline, but 'port' is left entirely unexplained (port name from list_ports vs. a device path is ambiguous) and the newline parameter's configurable format is never mentioned.

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 and resource: 'Send text plus a newline to an open port'. The newline-appending behavior and the target (an open port) are both explicit, which distinguishes it from read_lines and clear_buffer. It stops short of naming a sibling tool directly, so sibling differentiation is only implicit.

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?

Usage is implied rather than stated: describing the port as 'open' hints that open_port must run first, and the firmware-CLI example suggests a command-entry scenario. There is no explicit when-to-use guidance, no when-not-to-use, and no named alternative among the nine siblings.

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