engineering.hardness_convert

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

Annotations already declare readOnly/idempotent/closed-world, so the description adds the real value: the approximation is linear, input constraints (value > 0, HRC < 88.887) exist, and the result is an unrounded Decimal string. It does not say what happens on invalid input (error vs clamp), which is the only meaningful 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?

Four dense sentences, front-loaded with purpose then constraints then caveats then output format — each sentence carries distinct information. Slightly dense but no filler.

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?

For a 3-parameter read-only conversion with an output schema, the description covers all the agent needs: allowed scales, input validity, precision limits, and result formatting. Nothing material is missing.

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 0% and none of the three parameters have enums, but the description compensates: it constrains from_scale/to_scale to HV/HB/HRC and specifies the value domain (positive, HRC < 88.887, decimal string). It never states the literal string form expected for scale names, leaving ambiguity an agent could stumble on.

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 (환산한다/converts), a specific resource (steel hardness), and the exact scales involved (HV, HB, HRC), even giving the approximation formulas. An agent can immediately tell this apart from generic converters such as units.convert or engineering.si_prefix_convert.

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?

Gives explicit applicability bounds (valid around HV 240–800) and an explicit alternative for cases outside that range or for non-ferrous metals (ASTM E140 tables). It does not name a sibling tool as an alternative, which keeps it from a 5.

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