takeScreenshot

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the core action (capturing viewport) and output format (base-64 PNG data URL), and mentions the browser client requirement. However, it doesn't address potential limitations like viewport size constraints, performance implications, or error conditions.

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 perfectly concise with two sentences that each earn their place: the first specifies the action and output, the second states the prerequisite. No wasted words, and the most critical information (what it does) is front-loaded.

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 tool with no parameters, no annotations, and no output schema, the description provides adequate basic information about what the tool does and its prerequisite. However, it doesn't describe what the returned data URL looks like, potential size limitations, or error scenarios, leaving some contextual gaps.

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 has zero parameters, and schema description coverage is 100%. The description appropriately doesn't discuss parameters since none exist. It focuses instead on the tool's behavior and prerequisites, which is the correct emphasis for a parameterless tool.

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 specific action ('Capture the current 3D viewport') and output format ('return a base-64 PNG data URL'), distinguishing it from all sibling tools which manipulate scene objects, execute scripts, or manage scenes rather than capturing visual output.

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 provides clear context for when to use this tool ('Requires a browser client to be connected'), establishing a prerequisite condition. However, it doesn't explicitly state when NOT to use it or name specific alternative tools for similar functions.

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