MCP Screen Text

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 states the core function but lacks details on traits such as performance expectations (e.g., speed, accuracy), error handling (e.g., invalid image formats), or output format (since no output schema exists). This leaves significant gaps for an agent to understand how the tool behaves beyond basic OCR.

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 a single, efficient sentence that directly states the tool's function without unnecessary words. It is front-loaded with the core purpose ('Extracts text from an image using OCR'), making it highly concise and well-structured for quick understanding.

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 complexity of an OCR tool with no annotations and no output schema, the description is incomplete. It doesn't address key contextual aspects like what the output looks like (e.g., plain text, structured data), potential errors, or performance constraints. This makes it inadequate for an agent to fully grasp the tool's behavior and usage.

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 description coverage is 100%, with clear documentation for both parameters (imagePath and language). The description adds no additional meaning beyond what the schema provides, such as explaining OCR limitations or language code nuances. This meets the baseline score of 3, as the schema adequately covers parameter semantics.

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 action ('extracts text') and resource ('from an image using OCR'), making the purpose immediately understandable. However, it doesn't differentiate from sibling tools like 'capture_screen_and_extract_text', which suggests a similar function but with additional capture steps.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an image file), exclusions, or comparisons to sibling tools like 'capture_screen_and_extract_text', leaving the agent to infer usage context.

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