fit_class

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

With no annotations, the description carries the full burden and does well: it discloses units (mm), the version-1 scope limitation (hole-basis H, clearance letters h/g/f/e), the exact return shape, and the two error conditions (>500 mm out-of-table size, unsupported code). It lacks nothing critical for a pure lookup/calculation tool.

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?

Three dense sentences, front-loaded with purpose, then scope, then return/errors. Nearly every clause earns its place; the only mild cost is packing the return object and error cases into a single long sentence.

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?

There is no output schema and no annotations, so the description must supply the contract, and it does: it enumerates return fields and states the failure modes. Complete enough to call correctly and interpret results, though it omits any note on default behavior when 'fit' is omitted (only inferable from the schema default).

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 0%, so the description must compensate, and it does: 'fit' is illustrated with the format 'H7/g6' (matching the default), and 'basic_size' is given units (mm) and a range (>500 mm errors). This meaningfully extends the bare {fit, basic_size} 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 resource and standard: 'ISO 286 limits for a fit code (e.g. H7/g6), in mm,' which tells an agent exactly what the tool computes. It does not, however, name or distinguish itself from plausible siblings such as fit_check or fit_page, so sibling differentiation is absent.

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?

It scopes the tool ('v1 covers a hole-basis H with shaft clearance letters (h, g, f, e)'), which implies when it applies, but it never says when to prefer this over fit_check or other fit-related siblings. Usage is inferable from the scope statement rather than explicitly guided.

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