screenshot

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

With no annotations, the description carries the burden and discloses several useful traits: only public URLs, full-page default, an optional delay for late-loading content, the return being a local output path, and the $0.01 cost. It stops short of auth requirements, overwrite behavior for output_path, or rate limits.

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 compact sentences with the capability front-loaded and the use cases and cost trailing appropriately. The trailing '$0.01' is slightly abrupt but earns its place as cost disclosure.

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?

For an 8-parameter tool with no annotations and no output schema, the description covers the primary use and return shape but leaves output_path, idempotency_key, format, and quality semantics unexplained. Adequate but not complete for the tool's complexity.

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 only 25% (quality and delay_ms only), so the description compensates partially by naming the device presets, the full-page default, and the delay option. However it says nothing about output_path, idempotency_key, or format/quality interplay, leaving several parameters undocumented in both places.

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?

States a specific verb+resource (screenshot a public URL) and the scope (device presets, full page by default), which cleanly separates it from text-extraction siblings like url_to_markdown. An agent can tell what it produces (an image of a page as a browser sees it) without opening the schema.

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 lists intended scenarios (visual checks, monitoring, documentation, archiving), which implies when it is useful, but never contrasts with alternatives such as url_to_markdown or render, nor states when it should not be used. Usage is implied rather than routed.

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