Extract Text (OCR)

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true — the safety profile is fully covered. The description adds value by disclosing the cost ($0.05 USDC on Base), which is genuinely useful behavioral information an agent wouldn't know from annotations alone. The _payment parameter flow is also referenced in the schema though not the description.

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?

Two sentences, zero wasted words. The first sentence states the core function and the second adds the key cost information. Every word earns its place and the description is front-loaded with the primary purpose.

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?

The tool has a full input schema covering 5 params, an output schema exists, and annotations fully cover read-only/idempotent/open-world behavior. With an output schema present, the description needn't explain return values. The only potential gap is guidance on format choices or language nuances, but given the rich schema and annotations, the description is adequate for agent selection and invocation.

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 all 5 parameters are already documented in the input schema. The description adds no additional parameter context beyond what the schema provides — baseline 3 is appropriate when the schema carries the full documenting burden. It doesn't clarify format semantics (text vs json vs hocr) beyond what the schema enumerates, but that's not required at 100% coverage.

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 verb+resource ('Extract text from an image using OCR'), which is specific and unambiguous. The description distinguishes it from siblings like image.screenshot (which captures screenshots) and document.parse (which likely parses documents). The tool name image.ocr — with section 'image.' separating it from qr.* and document.* siblings — plus an explicit OCR purpose leaves no ambiguity.

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 states what the tool does but provides no explicit when-to-use guidance or exclusions versus alternatives. There's no mention of alternatives like document.parse for document-based extraction. The payment context ('Costs $0.05 USDC on Base') is helpful contextual usage guidance but doesn't address when to reach for this tool versus siblings.

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