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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful output behavior beyond annotations: overview images are labeled with times, `at` returns up to 8 screenshots, large size helps read small text, and pinned comments appear as numbered orange markers named in the caption.

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?

The description is short, front-loaded, and every sentence adds useful information about mode selection, size, or output markers. There is no redundant or filler text.

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 read-only screenshot retrieval tool with full schema coverage and annotations, the description provides enough context about both operating modes and the visual output. The only unmentioned parameter is `unmarked`, which the schema documents.

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. The description adds real meaning for `at` and `size` beyond the schema, but it never explains the `unmarked` parameter, leaving one semantic gap.

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 clearly identifies the tool as returning screenshots from a recording and explains the two modes: overview frames without times versus specific frames with `at`. This is specific enough to distinguish it from siblings like get_transcript or get_console.

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 explicitly explains when to omit `at` versus when to provide it, including examples such as error times or spoken moments, and when to use `size: large`. It does not name alternative sibling tools or state exclusions, so it falls short of a full when/when-not/alternatives guide.

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