截图 OCR

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

With no annotations, the description carries the burden of behavioral disclosure. It explains that extraction is character-by-character and preserves reading order and layout, which are key behaviors. It does not mention potential side effects or limitations, but the core behavior is adequately described.

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 extremely concise, consisting of two short sentences. The first sentence covers functionality and examples, the second specifies when to use. Every word adds value, with no redundancy or unnecessary detail.

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 6 parameters and presence of an output schema, the description provides sufficient context: it explains the core functionality, typical use cases, and when to invoke the tool. It does not elaborate on complex parameters like detail_level or region, but these are covered in the 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?

Schema description coverage is 100%, so each parameter is already well-documented. The tool description adds no new parameter-specific information beyond overall context. Baseline of 3 is appropriate as it neither enhances nor detracts from the schema.

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 extracts text from screenshots character by character, preserving reading order and layout, and lists specific content types (code, terminal, errors, documents). This distinguishes it from sibling image analysis tools that may not specifically perform OCR with layout preservation.

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 explicitly says 'use when you need to read out the text in the image,' providing a clear condition for use. However, it does not mention when not to use this tool or suggest alternatives, which slightly limits guidance.

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