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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context by defining the deal criterion (30-day average low comparison, separate branch for new products), which is essential for interpreting results. It stops short of saying how many results come back by default, whether they are ranked, or why an item might be excluded.

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 with the core definition front-loaded; nothing is wasted. The nested parenthetical about new products is slightly awkward to parse but conveys a necessary edge case, so it 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?

For a simple two-parameter read tool this is mostly adequate, and the criterion definition covers the conceptual gap. With no output schema, though, the description never sketches the return shape (e.g., that it yields products with their cheapest listing and comparison price), and it omits the limit parameter entirely.

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% across two parameters, so the description has to carry the load. It explains the 'category' parameter's meaning and where to source valid keys (list_categories), which the bare string schema does not. The 'limit' parameter is never mentioned, leaving its purpose, default of 10, and maximum of 25 undocumented outside the schema constraints.

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 gives a specific resource ('products') plus the exact selection criterion: cheapest listing well under the product's own 30-day average low, with a separate rule for new products. That is far more specific than the bare name 'deals'. It does not explicitly contrast itself with the sibling price_moves, so an agent must infer the difference between 'deals' and 'price moves'.

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 tells the agent that category is optional and that valid keys come from list_categories, which is a useful pointer to a sibling. However, there is no explicit guidance on when to choose this tool over price_moves or price_per_unit, and no note on when the tool returns nothing or how results are ordered.

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