ocr_screen

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

With no annotations, the description carries the behavioral disclosure burden. It discloses that OCR requires an optional Python dependency and a system-level Tesseract installation, and that the tool fails gracefully with installation guidance instead of crashing. This is valuable beyond the basic function, though it does not cover all edge-case 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 text is compact, front-loaded with the purpose and fallback condition before dependencies and parameter details. Every sentence adds information, though the dependency install instructions make it slightly longer than strictly necessary.

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?

It covers purpose, fallback condition, dependencies, failure mode, and the lang parameter, and an output schema exists so return format need not be described. However, the serial parameter remains unexplained, which is a real gap for a tool with only two parameters and no schema descriptions.

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?

Schema description coverage is 0%, so the description must document parameters. It explains lang well (Tesseract language code, multi-language via 'eng+hun'), but it does not mention the serial parameter at all, leaving half the parameters undocumented.

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 names a specific verb and resource ('OCR-based text recognition on the screen') and immediately distinguishes it from ui_dump by positioning it as the fallback for empty UI dumps in games, WebView, Canvas, and custom-drawn UI. This makes its role clear among the sibling tools.

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?

It explicitly states when to use this tool: when ui_dump returns an empty list, with concrete scenarios. The word 'fallback' plus the named ui_dump alternative gives the agent a clear selection rule.

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