barcode_lookup

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

Annotations include readOnlyHint=true, and the description aligns by calling out the underlying GET endpoint. The description adds useful context about the return fields and the 'thin wrapper' nature, but does not disclose error handling, rate limits, or edge-case behavior. With annotations covering the read-only aspect, this is sufficient but not exceptional.

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, dense sentence that front-loads the core purpose ('Look up a UPC/EAN barcode') and packs in the output fields and endpoint reference without waste. Every phrase earns its place.

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's simplicity (1 parameter, no output schema), the description covers the essentials: input format, expected output, and the specific endpoint. It does not explain behavior on invalid/missing barcodes or elaborate on the 'optional path for boxed goods', but these are minor gaps for a thin wrapper lookup.

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 provides no description for the required 'code' parameter (0% coverage), but the description compensates by specifying 'UPC/EAN barcode', clarifying that the code is a barcode format. This adds meaning beyond the generic parameter name. However, it doesn't detail allowed formats, validation, or optional path handling for boxed goods.

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's function: 'Look up a UPC/EAN barcode → name/manufacturer/model'. It names a specific resource (UPC/EAN barcode), a verb (look up), and the expected output fields. This distinguishes it from sibling tools like search_items or get_item, as it's specifically barcode-based lookup.

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 context is implied by the tool's name and description: use it when you have a UPC/EAN barcode to resolve. However, it does not explicitly contrast with alternatives (e.g., search_items, get_item) or provide when-not-to-use criteria. No exclusions or alternative tool recommendations are mentioned.

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