screenshot

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

With no annotations, the description must carry the behavioral disclosure burden. It states the output shape but does not mention failure behavior, size limits, load consequences, or whether the operation is purely safe/read-only. The 'public URL' constraint is helpful but insufficient.

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, dense sentence that front-loads the core action and result. Every clause contributes useful information, and there is no repetition of schema data.

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?

Despite an output schema covering the return value, the tool has five parameters and zero schema descriptions, so the definition should compensate by explaining parameter semantics and operational constraints. It does not; it only covers format and output shape, leaving important calling details undocumented.

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 0%, and the description only compensates for format by listing PNG/JPEG/WebP. There is no explanation of how width, height, full_page, or url should be provided, beyond their raw titles and defaults. Most parameter meaning is left to the agent to infer.

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?

Description clearly specifies the operation ('Capture a public URL as an image'), the output formats (PNG/JPEG/WebP), and the return shape. It is specific, but it does not explicitly differentiate from sibling tools pdf and extract, so it loses a point.

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?

It implies use by saying 'public URL', which hints it will not work against authenticated pages, but there is no guidance on when to prefer screenshot over pdf or extract, nor any mention of when not to use it. No alternative routing is provided.

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