browser_screenshot

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the return format (a data URL) and the scope limitation implied by "visible" (viewport rather than full page), but says nothing about permissions, whether it is a safe read-only operation, or failure behavior.

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?

A single front-loaded sentence with no wasted words; the resource and output format come before any qualifying detail.

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 one-optional-parameter tool with no output schema, the description covers what the tool produces (data URL) and what it targets (active or specified tab). The remaining gap is the unstated distinction between viewport-only capture and any full-page option, plus no mention of error cases.

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 100%, so the baseline is 3, but the description adds genuine meaning the schema lacks: it clarifies that omitting the optional tabId targets the *active* tab rather than being a no-op. That default-target behavior is not expressed anywhere in the schema.

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 names a specific verb and resource ("Captures a visible screenshot ... of the active or specified tab") and states the output form, which clearly separates it from siblings like browser_get_dom or browser_evaluate. It is unambiguous, though it does not explicitly name a contrasting sibling to route against.

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?

There is no guidance on when to reach for a screenshot versus alternatives such as browser_get_dom, nor any stated prerequisites. Usage is only implied by the tool name and purpose.

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