serial_monitor

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

With annotations already declaring readOnlyHint, openWorldHint=false, and destructiveHint=false, the description adds valuable behavioral context: the default and maximum listening duration, and that it returns both raw output and anomalies. It doesn't cover potential blocking behavior or output format details, but the added context is meaningful.

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?

Two tightly written sentences with no waste. The core purpose and duration constraints are front-loaded, followed immediately by the usage rule and alternative.

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 the tool's simplicity (one optional parameter, no output schema), the description provides everything an agent needs: what it does, when to use it, how long it runs, and what it returns. Annotations already cover safety, so no critical gaps remain.

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 the single parameter is fully documented in the schema. The description repeats the default (30 s) and max (300 s) without adding new syntax or format details beyond what the schema provides, which is the baseline 3.

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 states a specific verb (listen), resource (device output and anomalies), and scope (fixed time window), clearly distinguishing it from serial_wait_for. It also implicitly differentiates from read-once siblings like serial_read by emphasizing monitoring over a duration.

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?

It explicitly states when to use this tool ('when you do not know what to expect') and names the alternative serial_wait_for for when you do know what to expect. This is a textbook when/when-not/alternative guidance.

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