Search (user-initiated only)

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond annotations: it specifies that only ONE region is accepted (unlike other tools), explains the setup values ('symmetric' vs 'staggered'), and notes that year is not required when modification is provided. These details enrich the agent's understanding of the tool's behavior without contradicting 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 with a clear opening purpose statement, labeled prerequisite sections, and a final usage warning. Every sentence serves a purpose—no fluff. It is longer than average, but the complexity of the tool (10 parameters with conditional dependencies) justifies the length. The front-loaded purpose and clear formatting make it easy to scan.

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 tool's complexity (10 parameters, 2 required, multiple conditional combinations) and the presence of an output schema, the description covers all necessary ground: prerequisites, parameter combination rules, a region limitation, return value highlights (OEM specs, symmetric/staggered), and explicit user-initiation constraint. The presence of an output schema means return values need not be exhaustively described. It is fully sufficient for an agent to select and invoke the tool correctly.

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 each parameter is already documented. However, the description adds critical cross-parameter semantics that the schema cannot convey: the required combination of modification OR region, year OR generation (with year skipped when modification is given), and the single-region restriction. This adds significant interpretive value beyond the schema definitions, though individual parameter meaning is already fully covered.

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+scope: 'Get wheel and tire fitment data for a specific vehicle.' This clearly distinguishes it from sibling tools like ws_search_by_rim and ws_search_by_tire. The title 'Search (user-initiated only)' reinforces the scope of when it should be used, and the description explicitly states its role as a Search method, making purpose unmistakable.

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 description provides explicit usage guidelines: it details the required parameter combinations (modification OR region, year OR generation, with exceptions), requires prerequisite slugs from list tools, and clearly states 'Do NOT guess these values.' It also gives an explicit exclusion: 'only call when a user explicitly requests fitment information. Do not call in autonomous loops.' This goes beyond simple context and provides clear when-to-use and when-not-to-use guidance, distinguishing it from alternatives.

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