serial_send_break

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

Annotations show readOnlyHint=false and destructiveHint=false, consistent with sending a non-destructive signal. The description adds behavioral context by explaining the break holds TX line low and lists device interpretations, which goes beyond annotations.

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 well-structured with a brief intro, a bullet-like list of examples, and an Args section. It is informative without unnecessary verbosity, though the list of devices could be slightly condensed.

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?

Given no output schema, the description covers the tool's purpose, parameters, and usage context well. It lacks details on the immediate result or return value, which may matter for an agent, but is otherwise complete for a fire-and-forget operation.

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?

Although schema description coverage is 0%, the description's Args section provides clear explanations for both parameters: duration with a default and typical range, session_id with meaning and optionality. This adds significant value beyond the schema types and defaults.

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 the tool sends a serial break signal, and provides specific examples of devices that interpret it (U-Boot, Cisco IOS, etc.). This distinguishes it from siblings like serial_write or serial_command, which handle regular data or commands.

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 gives context on when to use the break signal (e.g., interrupt autoboot, break into ROMMON) and notes that session_id is optional if only one session is open. However, it does not explicitly contrast with siblings or state when not to use it.

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