Cross-reference metric ⇄ inch threads

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

The description adds behavioral context beyond annotations (readOnlyHint=true): it returns the closest standard counterpart, major diameters, pitch/TPI, and match closeness. It also reveals special behavior (full chart when designation omitted). No contradictions with 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 two concise sentences. The first sentence covers purpose and outputs; the second covers special behavior. No wasted words, and essential information is front-loaded.

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 no output schema, the description adequately explains return values (major diameters, pitch/TPI, closeness). It covers the optional parameter behavior. A minor gap: it doesn't clarify if multiple matches are possible or if the closest match is exact.

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 100%, and the description enriches the parameter 'designation' with examples (e.g., 'M8', '5/16-18 UNC') and the key behavior of omitting for full chart. This adds practical meaning beyond the schema description.

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 clearly states the tool's purpose: 'Look up the closest standard counterpart of a thread designation (ISO metric coarse ⇄ Unified UNC), with major diameters, pitch/TPI and how close the match is.' It uses a specific verb ('look up') and resource ('thread designation'), and distinguishes from siblings (conversion/extraction tools).

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 clear usage context: cross-referencing metric and inch threads. It also hints at when to omit the parameter ('omit `designation` to get the whole cross-reference chart'). However, it does not explicitly state when not to use or mention alternatives, though siblings are clearly different.

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