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

Annotations already declare the tool read-only and idempotent, and the description adds genuinely useful behavior: in-stock offers with known net prices are prioritized and results are ordered by net EUR price. It also enumerates returned attributes, including the outbound link, going beyond the minimal safety profile.

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 front-loaded sentence that states the core scope, ordering, and the full set of included data points. Every phrase earns its place and there is no fluff or repetition.

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 read-only single-add-on comparison tool, the description covers the essential behavioral rules: what is included, what is prioritized, and how results are ordered. The output schema covers return structure, and annotations cover safety, so the main remaining gap is the undocumented slug semantics.

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 only parameter, 'slug', has no schema description, and the tool description never explicitly states that slug identifies the add-on. The phrase 'one add-on' hints at the resource, but the mapping from parameter to meaning is left implicit, which is risky for an agent.

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 exact resource ('one add-on') and output scope ('every store offer'), and it specifies sorting behavior and included fields. It doesn't explicitly contrast with sibling tools like price_history or get_addon, but the single-add-on scope makes its purpose identifiable.

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 phrase 'for one add-on' implies when to use the tool, but the description gives no explicit guidance about when not to use it or which sibling tool to prefer in other scenarios. It leaves the choice between compare_prices, price_history, and list_deals to inference.

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