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

Annotations already declare read-only, idempotent and open-world behavior, so the bar is lower, yet the description adds material context the annotations lack: this is a paid call costing 0.05 USDC via x402, and compatibility is not inferred from title similarity. The pricing/auth disclosure is exactly the kind of trait an agent needs before invoking.

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 compact sentences with the coverage list front-loaded and the pricing disclosure at the end. Every sentence earns its place, though the list-style middle sentence is dense.

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?

An output schema exists so return values needn't be described, and annotations plus the pricing note cover the safety/cost profile. The definition is still incomplete on parameter usage and sibling differentiation, which an agent needs to call the right tool with the right arguments.

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 0%, so the description carries the full burden of explaining query, part_number and manufacturer. It does not: it never clarifies that query and part_number are alternative anyOf inputs, nor what manufacturer is for. 'Exact-part' hints that part_number is the precise path but adds no real syntax or relationship meaning.

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 resource (exact-part intelligence) and enumerates the coverage: lifecycle status, discontinuation, successor/substitute relationships, documents and sourcing. The 'exact-part' qualifier implicitly distinguishes it from the fuzzy-looking sibling parts_search, but no sibling is named explicitly, so the boundary is inferable rather than stated.

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?

No when-to-use, when-not-to-use, or alternative guidance is given, even though siblings parts_search and parts_status clearly overlap in domain. The only routing-adjacent sentence ('Compatibility is never inferred from title similarity alone') is a behavioral caveat, not usage guidance.

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