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

Annotations already establish the tool as read-only, idempotent, and non-destructive. The description adds valuable context beyond those hints: it requires no key, charges nothing, returns data from the platform's published product record, and behaves informatively on unknown slugs. The only minor gap is not detailing the exact output shape, but the output schema already covers that.

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 sentences, front-loaded with the core return value and followed by cost/authentication and usage guidance. Every sentence adds distinct value with no repetition of annotations or schema details, making it appropriately sized and easy to scan.

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 single-parameter read-only tool with a rich output schema, this description is complete. It explains the return contents, the relationship to fetch_data, the authentication/cost profile, and the error behavior. An agent has everything needed to select and invoke the tool correctly.

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 100% and the schema already describes the parameter as 'a product slug from list_products.' The description reinforces this by explaining slug-based lookup and adding the unknown-slug behavior, which gives the agent a clearer expectation of what happens with invalid input. This meaningfully extends the schema's bare 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 opens with a specific verb and resource: 'Returns one product by slug' and lists exactly what the returned catalogue entry contains (price, licence, lifecycle state, specification address, callable routes). It also distinguishes itself from fetch_data by positioning get_product as the source for route names, making its role clear relative to siblings.

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 gives explicit sequencing guidance: 'Use it before fetch_data — the route names come from here.' It also explains how to recover from an unknown slug by stating that the response returns the slugs the catalogue serves. This is actionable and removes ambiguity about when to call this tool.

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