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

No annotations are provided, so the description carries the full burden. It discloses the checksum algorithm (alternating weights 1 3, right-to-left, check digit formula), which is helpful. However, it doesn't state whether the tool returns a boolean or throws errors, or what happens on invalid input format (e.g., non-numeric characters). The presence of an output schema mitigates this somewhat, but basic behavioral details are missing.

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 sentence that packs all critical information: supported barcode types, digit lengths, and the checksum algorithm. No wasted words, front-loaded with the core purpose. Excellent conciseness.

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 tool has a single required parameter, an output schema (not shown here but present), and 100% schema coverage, the description is largely complete. It explains what formats are valid and how the check works. A minor gap is not explaining return format or error behavior, but the output schema likely covers returns.

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 has 1 required parameter with 100% coverage (value is described as 'identifier or value to check'). The description adds significant meaning by specifying exactly what formats are accepted (EAN-8, UPC-A, etc.) and the validation algorithm, which goes beyond the schema's generic 'identifier or value to check' description.

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 it validates barcode checksums for EAN-8, UPC-A, EAN-13, and GTIN-14, with specific digit lengths. The verb 'validates' combined with the explicit resource ('barcode checksum') makes the purpose unambiguous and distinct from sibling tools like iban_validate or isbn_validate.

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 implicitly suggests when to use this tool—when validating barcode checksums—but provides no explicit guidance on when not to use it or when to prefer one of the sibling tools (e.g., luhn_validate for credit cards, iban_validate for IBANs). The list of supported barcode types is helpful but lacks exclusionary context.

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