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

Annotations already declare readOnlyHint, idempotentHint and closed-world, so safety is covered. The description goes further by disclosing the return shape (verified/unknown status plus exploded-view position) and a real behavioral caveat about how missing data is interpreted, which materially affects how an agent should treat an 'unknown' result.

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 short sentences, front-loaded with the core action, followed by return information and the epistemic caveat. Every sentence carries distinct, non-redundant 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?

With no output schema, the description usefully covers the return values, and annotations carry the safety profile; the fully documented schema covers inputs. Only the routing relative to sibling lookup tools is unaddressed, a minor gap for a low-complexity 4-parameter 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%, so all four parameters (including the optional brand and agent_id) are already documented in the schema. The description adds no parameter-level syntax or constraints beyond that, so the baseline of 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 names a specific verb (verify), a specific resource (spare-part article number) and the exact relationship being tested (linkage to a heat-pump model), which separates it from listing-oriented siblings like get_parts_for_model and search_spare_parts.

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 purpose sentence implies the use case (checking whether one part fits one model), but there is no explicit when-to-use statement and no mention of the sibling tools an agent should prefer for lookup versus verification. Usage must be inferred from the purpose.

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