Screenshot

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

Annotations declare readOnlyHint=true, which is consistent with taking a screenshot. The description adds value beyond annotations by disclosing the side effect of saving a file to '~/.dev-browser/tmp/' and the return of both image and path. This informs the agent about persistent storage and output format.

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?

The description is a single sentence of 18 words, front-loaded with the verb and resource. Every word earns its place; there is no filler or redundancy. It is optimally concise for an agent to parse quickly.

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?

The description covers the basic purpose and output, but given the tool has 7 optional parameters and no output schema, it lacks details on error conditions, prerequisites (e.g., page must be loaded), and the exact format of the returned image (e.g., base64 or binary). It is minimally complete but not comprehensive.

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 each parameter has a description in the schema. The tool description does not add new parameter-level information beyond what is already in the schema. Baseline score of 3 applies as the description does not detract but also does not enrich parameter understanding.

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 explicitly states the action ('Take a PNG screenshot'), the resource ('a named page'), and the output ('return the image plus the saved path'). It effectively distinguishes from siblings like dev_browser_snapshot and dev_browser_goto by specifying the capture format and output type.

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 description provides no guidance on when to use this tool versus alternatives (e.g., dev_browser_snapshot). It does not mention prerequisites (e.g., page must be open via dev_browser_goto) or when not to use it. An agent would need to infer usage from context.

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