Fit Between a Hole and a Shaft

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

With no annotations, the description carries the burden and does well: it declares output units (millimetres), the sign convention ('a negative minimum clearance means the fit can interfere'), and scopes itself as a pure geometry report rather than a recommendation. It does not say what happens when a class is invalid or unavailable at the given nominal size, which is the remaining behavioral gap.

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?

Opens with the core operation and its return contents, then adds one short scoping sentence. No filler, and the most decision-relevant information (what comes back and in what units) 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?

An output schema exists, so return-value explanation is optional, yet the description still clarifies units and sign semantics. Parameters are fully covered. Only failure/edge behavior for invalid or inapplicable class-size combinations is unaddressed.

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 all three parameters are already documented, giving a baseline of 3. The description adds the combined format '12 H7/h6' and restates the shared-nominal constraint, but no new detail on accepted class syntax beyond the schema's own examples.

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 ('Return the resulting fit between one hole class and one shaft class at the same nominal size') and enumerates exactly what is returned: fit type, min/max clearance, max interference. The example '12 H7/h6' makes the operation unambiguous and clearly separates it from sibling limit/grade lookups.

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?

Supplies a concrete usage example and draws an explicit boundary: it reports fit geometry, not whether the fit suits a joint, which 'is the caller's decision.' That prevents misuse for design-selection questions. It stops short of naming which sibling to call for alternative needs (e.g. limits_of_size or iso286_applicability).

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