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

Annotations already declare readOnlyHint, idempotentHint and closed-world, so the safety profile is covered. The description adds real value by naming what the response contains (normalized price, stock, purchaseability, identifiers, attributed URL) and by noting the agent_id attribution behavior in the schema. It stops short of saying what happens on an unknown identifier, which matters for a lookup tool.

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, no filler: the operation and accepted identifiers come first, the return payload second. Every clause earns its place and nothing is repeated from the title.

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 summarizes the returned fields, which is the main thing absent from structured data. The remaining gap is failure behavior (not-found, invalid identifier, rate limits), minor for a simple read tool.

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 both parameters are documented there, including the three accepted identifier formats and the referral-only role of agent_id. The description restates the identifier formats but adds no new syntax, format, or default guidance, so the schema does the heavy lifting.

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 (fetch) and resource (one Energirör webshop product) and enumerates the accepted identifier schemes (UUID, HWS/RSK, SAP material number). It is clear on its own, though it never explicitly contrasts itself with the sibling search_products, leaving the single-vs-list distinction to inference.

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 only implied: 'one product' suggests a point lookup rather than a search, so an agent can infer it belongs before/after a search. There is no explicit statement of when to prefer this over search_products or check_compatibility, and no prerequisites are given.

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