search_parts

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

With no annotations, the description carries the behavioral burden and does well: all words must match, Japanese/English handling, terse katakana naming pitfalls, fallback strategy, VIN-driven catalogue selection, and fitment sorting. It omits pagination/limit behavior and result size, but discloses the traits that most affect correct invocation.

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?

The core behavior and query modes are front-loaded, and the fallback advice is placed immediately after the primary matching rule. It is dense but contains little waste, though the katakana example could be tightened.

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 an eight-parameter search tool with no annotations and no output schema, the description covers query semantics, language pitfalls, fallback behavior, VIN effects, and sorting. Missing pagination and limit semantics are minor given the high schema coverage.

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 already 88%, so the baseline is 3, but the description adds meaningful semantics for the two most important inputs: query matching rules and VIN-driven catalogue selection plus fitment sorting. Other parameters such as limit, group, drive, and lang are left to the schema.

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 (search a catalogue for parts) and names the two supported query modes: description words or part number prefix. It is clearly distinguishable from siblings like get_part, get_table_parts, and list_groups.

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?

Gives a concrete recovery path when nothing matches (shorter word, English, or browse groups), and explains that supplying a VIN changes catalogue resolution and result ordering. It does not explicitly contrast with get_table_parts or state hard exclusions, so it falls short of a full when/when-not routing guide.

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