screen_info

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

readOnlyHint=true already establishes this is a safe read, and with zero parameters there is little risk behavior to disclose. The description adds the returned fields, which is useful since no output schema exists, but it omits any cost, caching, or freshness caveats for a live frame query.

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 compact fragment with the subject and payload front-loaded and no filler. Very terse, but nothing is wasted.

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 must carry the return-value burden, and it names three concrete fields. It is adequate for a trivial no-arg read, though it may not be exhaustive if more frame fields exist.

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?

The tool takes no parameters, so there is nothing to disambiguate; the baseline for zero-param tools applies. The description's enumeration of returned fields is a mild bonus but not parameter guidance.

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 resource (frame metadata) and enumerates the payload (resolution, pixel format, palette status). It is distinguishable from siblings like screen_text and screen_capture by implication, but it never names them to make the distinction explicit.

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 when-to-use context is given. It does not say whether this should be called before screen_capture, or how it relates to screen_text/session_info, leaving the agent to infer the choice.

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