Peekaboo MCP

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 and does so effectively. It explains the tool's capabilities in detail, mentions fuzzy matching for app identification, describes optional window details, and specifies default behaviors (item_type inference). However, it doesn't mention potential limitations like performance impact, permission requirements, or error conditions, preventing a perfect score.

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 well-structured with clear sections (Capabilities, Use Cases) and uses bullet points effectively. While somewhat lengthy, every sentence serves a purpose: explaining capabilities, providing examples, and demonstrating workflow integration. The version information at the end could be considered extraneous but doesn't significantly detract from the overall clarity.

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 3 parameters, 100% schema coverage, but no output schema or annotations, the description provides substantial context. It explains all three item_type options with practical examples, demonstrates parameter combinations, and shows how results feed into other tools. The main gap is the lack of output format description, which would be helpful given the absence of an output schema.

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?

With 100% schema description coverage, the baseline is 3. The description adds some value by providing concrete examples in the Use Cases section (e.g., 'Photoshop', 'Notes') and explaining the practical meaning of window details like 'bounds' for image capture. However, it doesn't significantly enhance parameter understanding beyond what's already documented in the comprehensive schema descriptions.

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 purpose: 'Lists various system items on macOS, providing situational awareness.' It specifies three distinct capabilities (running applications, application windows, server status) and distinguishes itself from sibling tools like 'analyze' and 'image' by focusing on listing rather than analysis or image capture. The description goes beyond the name 'list' to explain what specific items can be enumerated.

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 usage guidance through the 'Capabilities' and 'Use Cases' sections. It clearly indicates when to use each item_type: checking if an app is running before automation, finding specific windows for image capture, and getting server status. The description also references sibling tools ('image') for follow-up actions, creating a clear workflow context.

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