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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds real behavioral value by enumerating what comes back — customer price, replacement info, compatible models, exploded-view positions, and an attributed product URL — which matters because no output schema exists.

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?

It is a single front-loaded sentence with no filler; the lookup key is stated first and the return payload enumerated afterward. It is dense but every clause carries information, with only mild redundancy between 'attributed product URL' and the schema's agent_id note.

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?

Since there is no output schema, the description appropriately covers return content and, with annotations handling safety and idempotency, an agent has enough to invoke correctly. The one remaining gap is error/not-found behavior for an unknown article number, which is not addressed.

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%, so all three parameters are already documented in the schema, including agent_id's referral-attribution role and manufacturer's overlap-disambiguation role. The description only echoes article number and the 'attributed product URL', adding no syntax or format detail beyond the structured fields, so the baseline 3 applies.

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 states a specific verb and resource ('get one Energirör spare part') and specifies the lookup key (article number). It contrasts implicitly with the sibling search_spare_parts by emphasizing a single-part retrieval, but never names an alternative explicitly, so it falls short of full sibling differentiation.

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 article number' — an agent can infer this is the single-lookup path versus search_spare_parts / get_parts_for_model. However, there is no explicit when-to-use/when-not or named alternative, so guidance is only hinted at.

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