Get the user's most recent SlimSnap capture

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

Annotations declare readOnlyHint=true, and the description adds substantial behavioral context by detailing the return structure (OCR elements, bounding boxes, colors, annotations, pointer associations) and explicitly stating that no image is returned. This goes well beyond the annotation and clarifies what consumers can expect.

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 concise yet information-dense, with the primary action and return type front-loaded in the first sentence. The second sentence adds usage context and exclusions without redundancy.

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 it has no output schema, the description enumerates the returned data elements in enough detail to set expectations, and it explicitly states what is not returned (no image) and where to find pixel data. This makes the tool's behavior complete for an agent.

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 coverage is 100%, so the baseline is 4. No parameter semantics need clarification, and the description correctly focuses on output and usage rather than inventing parameter details.

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 returns the newest SlimSnap capture as structured JSON with specific contents, and distinguishes itself from siblings by explicitly noting 'Returns no image' and emphasizing 'newest' versus a generic get_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?

The description provides explicit when-to-use guidance: 'Use this whenever the user refers to their screen, their last screenshot, "this", "here", or something they just marked.' It also explains when not to use it, directing users to the pixel tool for genuinely visual questions, and implicitly differentiates from list_captures and get_capture.

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