screenshot

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

With no annotations, the description carries the full burden of behavioral disclosure. It only states that it captures a PNG screenshot, omitting key behaviors such as defaulting to the active tab, interaction with selector/ref, frame handling (frameId, allFrames), and fullPage behavior. It also does not describe the return format (e.g., base64 data or file path). This is a significant gap for a tool with multiple behavioral parameters.

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, front-loaded sentence with no filler. It delivers the core purpose immediately and avoids redundancy. This is an ideal structure for conciseness, even if content completeness is lacking elsewhere.

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 tool has six parameters, no required fields, and no output schema. The description is too minimal to cover the operational context: it does not explain default behavior (active tab), how selector/ref are used, frame-specific options, or the return value. Given the parameter count and absence of an output schema, the description should provide more guidance to enable correct invocation.

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 83% (5 of 6 parameters have descriptions), so the baseline is 3. The description adds no parameter-level detail beyond what the schema already provides; 'page or element' loosely maps to selector/ref but adds no new semantics. It does not compensate for the undocumented 'fullPage' parameter, but the high schema coverage keeps this at baseline.

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 states a specific verb and resource ('Capture a PNG screenshot') and clarifies scope ('page or element'). It is clear but does not differentiate from the sibling tool 'snapshot', which could also capture visuals. The mention of PNG and element scope adds specificity, so a 4 is appropriate.

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?

No guidance is provided on when to use this tool versus alternatives like snapshot, get_text, or get_html. The description is purely declarative and does not mention conditions, prerequisites, or exclusions. An agent is left to infer usage from the tool name and schema.

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