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

readOnlyHint=true already tells the agent this is a safe read, so the description's job is lighter. It contributes the names of the fields returned (prices, units, stock alert levels, group, brand, supplier) and the backing endpoint GET /Products/{productGuid}, which is genuinely useful since no output schema exists. It does not mention not-found behavior or auth/rate-limit constraints, keeping it short of a 5.

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 compact clauses, with the operation and its identifier front-loaded and the payload enumeration and endpoint trailing. No filler sentences; every phrase carries information.

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 with no output schema, the description supplies the missing return-shape information via its field list, which is the main thing an agent would otherwise lack. The only omission is error/not-found handling, which is minor for this tool class.

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 100% and the single productGuid parameter is already documented with a UUID pattern, so the baseline is 3. 'By Guid' in the description merely restates the schema and adds no format or sourcing guidance (e.g., how to obtain the GUID).

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?

States a specific verb and resource ('Fetch a single product by Guid') plus the payload scope (prices, units, stock alert levels, group, brand, supplier). The singular 'single product' plus the GUID key cleanly separates it from unleashed_list_products and unleashed_get_product_stock without needing to open another schema.

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 is implied by 'by Guid' — you call it when you already have a product GUID — but the description never states when to prefer this over unleashed_list_products or unleashed_get_product_stock, and offers no exclusions or prerequisites.

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