pd_status

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

With no annotations, the description carries the full burden and does disclose a non-obvious operational constraint: reads consume captured events, so the tool is mutually exclusive with an active capture. It does not say what the caller actually gets when invoked during a capture (error, empty result, or silent loss), nor whether reading mutates any buffer outside capture mode.

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 short sentences, no filler, and the core purpose is front-loaded ahead of the constraint. Every sentence earns its place.

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?

No output schema exists, and the description compensates by naming the five snapshot fields. The key exclusion is documented. Remaining gap is failure-mode behavior when called during a capture, which matters for a tool whose whole caveat is unavailability.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The enumerated field list instead documents the return payload, which is a reasonable use of the space.

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+resource: "Read the PD-side status snapshot" with the returned fields enumerated (timestamp, VBUS, IBUS, CC1, CC2). This clearly separates it from the pd_capture_* and stream_* siblings, though it never explicitly names pd_capture_read as the counterpart.

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 gives an explicit when-not ("Not available while a PD capture runs"), which is real guidance, but never states the positive condition for use or names the alternative tool to call in that situation. The agent must infer that pd_capture_read/pd_capture_stop is the path forward.

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