Classified (user-initiated only)

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

Annotations already declare readOnlyHint=true and idempotentHint=true, lowering the bar, but the description adds meaningful behavioral context: results are broader than the OEM database (any physical fit), and warns that spacers or special bolts/nuts may be required and that rims must be verified against brake calipers and wheel arches. These are non-obvious behaviors not captured by annotations.

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 description is well-structured and appropriately sized for a complex tool: a clear opening sentence, a contrast with a sibling, return-value summary, usage tip, practical caveat, and a pointer to follow-up tool. Every sentence earns its place, and the front-loading makes it scannable.

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?

Given the high parameter count (16) and the presence of an output schema, the description covers all necessary context: purpose, differentiation from ws_search_by_rim, result contents, real-world usage, safety caveats, and a next-step pointer. The output schema handles return values, so the description's focus on functional context is sufficient.

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?

The schema already provides 100% parameter coverage with descriptions for all 16 parameters, so the baseline is 3. The description adds only limited extra semantics, such as explaining that fitment deltas (frontspace/backspace) relate to geometric calculations and highlighting sort='fitment', but it doesn't systematically elaborate on required parameters or tolerance options. It does provide some conceptual context (frontspace/backspace) that helps interpret bs_push/fs_poke and rim_bst_to/from, but not enough to push above baseline.

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 opens with a specific verb+resource: 'Find vehicle generations compatible with a given rim via geometric backspace calculations.' It clearly distinguishes from ws_search_by_rim by explaining the difference between direct 1:1 matching and advanced 2D geometric filtering, and states what the tool returns (make/model/generation, fitment deltas, load capacity). This is unambiguous and differentiates from siblings.

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 guidance is explicit: it contrasts with ws_search_by_rim, describes when this broader fitment search is appropriate, gives a concrete e-commerce use case ('This wheel fits: BMW X5, Audi Q7...'), and directs users to ws_find_vehicle_modifications_for_rim for drilling into a specific generation. Also provides a sort tip ('Use sort='fitment' to put the closest matches first').

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