screenshot_url

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

Discloses key behaviors: parallel execution across engines, waiting for elements, network idle, and exponential backoff retry. No annotations exist, so description carries full burden; it does well but lacks mention of output format or potential errors.

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?

Two sentences, no fluff. First sentence states main purpose, second adds key features. Efficient and well-organized.

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 8 parameters and no output schema, the description covers core functionality but does not describe the return value (e.g., image data or path). Otherwise comprehensive for a screenshot tool.

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?

All 8 parameters have schema descriptions (100% coverage). The description adds context by linking parameters to features (e.g., retryOnError for slow servers, waitForSelector for elements). Adds value beyond 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 clearly states the core action ('Take a screenshot of a URL') and resource (URL), and distinguishes from sibling tools like render_* and capture_animation by focusing on URL screenshots across multiple browser engines.

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?

Provides practical guidance: example URL (localhost:3000), waiting for selectors, and retry for slow dev servers. Could explicitly mention when not to use this tool vs siblings but the context is clear.

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