Browser 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 well: it discloses the return medium (a real PNG of the rendered page), what becomes visible (layout, design, text, images, errors), and that sessionId targets a specific headless session. It omits any note on capture latency, permission/attach requirements, or failure modes when no page is loaded.

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?

Three sentences, front-loaded with the action and result, then usage triggers, then the one parameter that matters. No filler.

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?

For a screenshot tool with no output schema and zero required parameters, the description covers output nature and invocation context well. A brief note on default mode behavior (extension vs headless) or empty/blank-page results would close the remaining gap.

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 both mode and sessionId are already documented in the schema; the description's note about passing sessionId to target a headless session largely restates that. Baseline 3 is appropriate since the schema does the heavy lifting and the description adds little new about 'mode'.

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 a screenshot of the current page as a PNG image') and characterizes the output as the rendered visual, which cleanly separates it from DOM-oriented siblings such as browser_get_dom or browser_snapshot.

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?

Explicitly names trigger points and siblings: after browser_navigate, after browser_click, or any time visual inspection is needed. It does not state when NOT to use it (e.g., prefer browser_snapshot/browser_get_dom for structural data), so it falls just short of a full when/when-not treatment.

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