Fit Class

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

Beyond the readOnlyHint annotation, the description discloses the exact return shape, coverage limits (v1), and failure conditions. This tells an agent what will happen on unsupported inputs, which is precisely the behavioral context not present in the annotations or schema.

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 packs scope, return fields, and error behavior into two compact sentences. It is dense but every clause contributes; the only inefficiency is the long parenthetical list of outputs, which is necessary because no output schema exists.

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?

With no output schema, the description compensates by enumerating the returned fields and specifying error cases. It leaves minor ambiguity about the extent of basic_size values and does not discuss alternatives, but for a two-parameter lookup tool it is nearly complete.

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. It explains the fit code format via example and units ('in mm') and implies basic_size limits through the >500 mm error condition, but it does not explicitly describe basic_size as a positive number or elaborate on the meaning of all returned fields in relation to the parameters.

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 identifies the operation as returning ISO 286 limits for a fit code and gives a concrete example ('H7/g6'), which makes the purpose unmistakable. It also scopes the supported cases (hole-basis H, clearance letters h/g/f/e), though it does not explicitly contrast it with sibling tools like fit_check.

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 implies when it applies: hole-basis H fits with shaft clearance letters h/g/f/e, and it states what triggers an error (out-of-table size >500 mm, unsupported code). However, it never names an alternative tool or says when not to use it versus siblings such as fit_check or tolerance_stackup.

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