screenshot

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

With no annotations, the description carries the full burden and does disclose output type (PNG ImageContent + metadata), the optional output file, and hard limits (6M pixels, 8192px/side, 4 MiB). It omits permission/auth requirements, whether the write of an output file is reversible, and pagination/streaming behavior, so disclosure is partial.

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 dense sentences, front-loaded with the output artifact before the scope exclusion and limits. Every clause carries information, though the telegraphic phrasing is borderline cryptic rather than genuinely concise-and-clear.

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 6-param, no-annotation, no-output-schema tool, the description covers the return artifact and size limits but leaves the three undocumented boolean params and permission/behavioral context unexplained. It is adequate but has clear gaps for correct invocation.

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 50% and three params (mkdir, full_page, overwrite) have no schema descriptions. "Optional safe output file" loosely gestures at output/mkdir/overwrite, but full_page and overwrite behavior are never explained, so the description only marginally compensates.

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 states a concrete verb+resource ("Return actual PNG ImageContent and metadata") and scopes itself with "No focus/resize/scroll," which implicitly separates it from act/scroll siblings. It is clear what the tool produces, though it never names a sibling tool explicitly.

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?

"No focus/resize/scroll" gives a when-not-to-use boundary, implying those interactions live in other tools. However, it does not say when to prefer screenshot over observe or how it relates to goto/list_tabs, leaving usage mostly implied.

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