screenshot

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

Annotations already declare readOnly/openWorld/non-destructive, so the bar is lower; the description still adds genuinely non-obvious behavior: the image is returned inline AND persisted to a file whose path is exposed, and it instructs the agent to surface that path to the user. It does not mention that a file write is a side effect, but nothing contradicts the annotations.

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 short sentences with the core action front-loaded and the output-handling instruction second; nothing is redundant and every clause carries information the agent needs.

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?

With no output schema, the description correctly takes on the return-value explanation (inline image plus file path) and covers the element-vs-page scope. It stops short of stating session prerequisites or what `full_page` does, which is the only remaining gap for a three-parameter 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?

Schema description coverage is 0%, so the description must carry the parameter burden. It explains `ref` meaningfully (an element ref from the latest snapshot), which is the only non-obvious parameter, but says nothing about `full_page` or `session_id`, leaving two of three 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 and resource ("Screenshot the current page") plus the scoped variant ("or just one element"), and ties the element case to a ref produced by the sibling `snapshot` tool. That implicitly separates it from snapshot/read_text, but the differentiation is left for the agent to infer rather than stated outright.

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 gives clear downstream guidance ("when the user wants to see something, show them that path") but never says when to prefer this over `snapshot` or `read_text`, nor any precondition such as needing an active session or a prior snapshot for `ref`.

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