take_screenshot

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

Annotations only declare safety (idempotent, non-destructive, not read-only); the description adds the cost model relative to get_accessible_tree and describes the response ('gives its size, and if it was shrunk, the scale'), which matters since there is no output schema. It does not explain state side effects such as pointer movement (park) or any rate limits, so it stops short of a 5.

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?

Front-loaded with purpose and output type before the cost caveat and per-parameter guidance; no filler sentences. It is dense to the point of being telegraphic in places ('vision checks nothing is told apart by color alone'), which slightly hurts readability.

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 a 7-parameter capture tool with no output schema and thin annotations, the description covers modality, cost trade-off, window-vs-screen choice, cropping, burst semantics, and the shape of the return value. It omits any mention of side effects like pointer parking or failure modes when a window title matches nothing.

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 100%, so the baseline is 3, but the description adds real meaning beyond the schema: it justifies window-over-screen, explains that crop is for taking 'a part', and frames vision as checking that nothing is distinguished by color alone. Only crop syntax and session naming are left entirely to the 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?

States a concrete verb and resource ('Take a picture of the screen, or of one window') and immediately clarifies the output modality ('RETURNED AS AN IMAGE'), which separates it from every text-based sibling. It also names the contrasting sibling get_accessible_tree, so an agent can route without opening a 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?

Gives explicit selection rules: prefer get_accessible_tree because pictures cost far more, prefer a window over the full screen, crop for a part, and use burst only for motion/animation/transition. When-not-to-use and alternatives are both stated.

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