capture_screenshot

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

With no annotations, the description carries the full burden and does so well: it discloses the capture mechanism (scrot, ImageMagick fallback), the window-matching fallback with matched_window_id=null, and the return payload shape. It even tells the agent to read the PNG at `path` rather than expecting inline image data.

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?

Front-loads the core action in the first sentence, then tacks on parameter and return detail. The scrot/ImageMagick implementation note is arguably extra but is useful for debugging failures; overall tight with little waste.

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?

Although an output schema exists (so return fields needn't be described), the description restates them helpfully, and it covers the display source, window matching, fallbacks, and platform. An agent has everything needed to invoke and consume this tool correctly.

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 coverage is 0%, so the description must compensate. It fully explains `display` (source and format, e.g. ':101') and `window` (title substring via xdotool, fallback semantics), but `out_path` is never mentioned, leaving one of three parameters undocumented.

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 ('Capture an OS-level PNG screenshot of the TestClient's X display') with the platform clarified. It is unambiguous and its function is distinct from every sibling tool listed, none of which capture pixels.

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 intended use (grabbing a visual of the running test client) is implied rather than stated, and there is no explicit when-to-use or when-not-to-use guidance. It does, however, explain the conditional behavior of the window-vs-full-display path, which routes the caller's choice.

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