screenshot

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

No annotations are provided, so the description bears full responsibility for behavioral disclosure. It only states the basic operation and return format, omitting important details such as JavaScript rendering behavior, timeout policies, image dimensions, privacy/security restrictions, or whether dynamic content is captured. This leaves an agent uninformed about key side effects and constraints.

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, short sentence that directly conveys the core functionality. It is not verbose and efficiently communicates the purpose. However, it could incorporate minimal additional context (e.g., output format clarity) without losing conciseness, earning a 4 rather than a 5.

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?

Given that there is no output schema, the description correctly mentions the return type (base64-encoded PNG). However, it lacks details such as image resolution limits, ability to capture dynamic content, error responses, or size constraints. For a simple 2-param tool, it is mostly adequate but not fully complete.

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 the baseline is 3. The description does not add any additional semantic value beyond the schema's parameter descriptions (e.g., it does not clarify that 'full_page' captures the entire scrollable height). The existing schema descriptions are sufficient for understanding the two parameters.

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 clearly states the action ('Take a screenshot'), the target ('a web page'), and the return format ('base64-encoded PNG image'). It effectively distinguishes from sibling tools (fetch_url, fetch_multiple, ping, crawl) which are about raw content retrieval or connectivity rather than visual capture.

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 does not explicitly state when to use this tool versus alternatives (e.g., 'Use this instead of fetch_url when you need the rendered page as an image'). Usage context is implied by the contrast with sibling tool names, but no explicit when-to-use or when-not-to-use guidance is provided.

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