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

Annotations already cover read-only, idempotent, open-world and non-destructive behavior, so the bar is lower; the description still adds genuine context that annotations cannot: the returned fields, the tokenizer rule that words under 3 characters are ignored, and a cost/consumption note ('one lookup per call') that matters given the get_usage sibling.

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?

Three front-loaded sentences with no filler: purpose and disambiguation first, then return shape, then constraints. 'Uses one lookup per call' is terse to the point of ambiguity about whether it refers to quota cost or result scope, but it is not wasted text.

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?

With no output schema, the description usefully enumerates the returned fields (barcode, title, brand, category, image), and it disambiguates the tool from its barcode siblings. The remaining gap is pagination behavior — how many results come back by default and how paging interacts with relevance ranking — which an agent must infer from page/per_page defaults.

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 coverage is only 33% — only 'query' carries a schema description — and the description compensates partially by explaining how the query string is tokenized and that results are 'best matches' (relevance-ordered). It says nothing about page or per_page, leaving result-set navigation undocumented in both structured and prose form.

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 a specific verb and resource ('Search products') and scopes it to title, brand or category lookups, then explicitly contrasts it with the barcode path ('when you have a name rather than a barcode'), which cleanly separates it from the sibling lookup_barcode tools.

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?

It gives a clear selection rule — use this when you have a name, use barcode lookup when you have a barcode — which is real routing guidance against the siblings. It stops short of an explicit 'when not to use' statement or naming lookup_barcode/lookup_barcodes directly, so a 4 rather than a 5.

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