pt_screenshot

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

No annotations are provided, so the description must disclose behavior. It states the action (takes a screenshot), the return format (base64-encoded PNG), and the context (current simulator screen). While it doesn't mention potential side effects or timing, none are expected for a screenshot tool, and the description covers the essential behavior.

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 two sentences with no redundant information. The first sentence states the primary action, the second clarifies the output format and usage, making it front-loaded and highly efficient.

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 tool's simplicity—one optional parameter, no output schema—the description fully covers the essential information: what it does, what it returns, and when to use it. Slight ambiguity about the exact 'screen' scope does not detract from overall completeness for a tool of this complexity.

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 schema already provides full coverage of the only parameter (udid) with the description 'Simulator UDID (uses active device if not specified),' which explains optionality and default behavior. The tool description adds no additional parameter semantics, so the baseline of 3 is appropriate.

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's function: 'Take a screenshot of the current simulator screen' with a specific verb and resource. It also distinguishes itself from sibling tools by being the only screenshot-related tool, and mentions the output format (base64-encoded PNG).

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 usage context with 'Use this to see what's currently displayed on screen,' which implies when to use it. It does not explicitly mention alternatives or exclusions, but among the sibling tools there is no competing screenshot tool, so the guidance is adequate for selection.

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