capture_screenshot

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

Annotations already declare read-only and idempotent. The description adds context about static rendering and the display server requirement, which goes beyond annotations. It does not contradict annotations and adds useful behavioral nuance.

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?

Three concise sentences, each serving a purpose: describing the action, distinguishing from alternatives, and stating a key requirement. No wasted words.

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?

Given the rich schema and annotations, the description covers purpose, usage, and an important environmental requirement. No output schema exists, so return values need not be explained. The tool is simple enough that this description is sufficient.

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 does not add additional parameter-level semantics beyond what the schema already provides. It mentions 'scene file' and 'viewport' but these are generic and not parameter-specific.

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 states the tool renders a scene file statically and saves the viewport as a PNG. It explicitly differentiates from live capture alternatives by saying 'No running game needed' and naming game_screenshot and run_and_capture.

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?

Provides explicit when-to-use vs alternatives: 'For live game captures, use game_screenshot or run_and_capture.' Also notes a prerequisite ('Requires a display server') and that no running game is needed, giving clear context for choosing this tool.

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