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

With no annotations, the description carries the full burden and does disclose important traits: per-page billing at €0.008, charges against the bearer API key, and the boxes default of true. It says nothing about page-count limits, file size limits, failure behavior, or whether repeated calls on the same page are re-billed, which matters for a paid mutation-free but costly call.

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 dense but front-loaded: capability first, then cost, then a labelled parameter block. Minor waste comes from the truncated language ellipsis ('… | en,ru') and repeating the language list, but nearly every clause adds information.

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?

An output schema exists, so the description needn't explain return values, yet it still flags line boxes and confidence. Cost, auth, and all four parameters are covered; only operational limits (max pages, file size, error semantics) are missing, which is a modest gap for a paid OCR endpoint.

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% and the schema types are uninformative (boxes and pages are just strings), so the description does all the work. It gives every parameter meaning: url accepts an image or PDF url, language enumerates the twelve supported codes and the comma-combination syntax, pages shows a range example, and boxes is clarified as a boolean defaulting to true.

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 the resource (images and scanned PDFs) and the deliverable (text plus line boxes and confidence), so an agent can tell this apart from caption or table_extract. It does not explicitly contrast itself with the sibling pdf_text tool, which is the most likely confusion point for PDFs.

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?

Usage is only implied: the phrase 'scanned PDFs' and the pages example ('1-3') hint that this is the choice for image-only documents, but no alternative is named and no when-not-to-use condition is given among ~80 siblings. An agent must infer the pdf_text vs ocr split itself.

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