Chain Drive

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

The description discloses the governing philosophy (lower of fatigue and impact envelopes), includes the actual formulas, explains how strands scale, and enumerates the return fields. This goes well beyond the readOnlyHint annotation and gives the agent a realistic model of what the tool computes and returns.

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 information-dense and front-loaded, with every clause serving a purpose. It is a single long paragraph, which makes it less scannable, but the inclusion of formulas and output details earns its length.

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?

The description compensates for the missing output schema by listing the expected result fields and explaining the capacity envelopes. It is not fully complete because the exact meaning of 'pass' and 'governing' is left implicit, and the '...' in the return object indicates unspecified fields.

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?

With 0% schema description coverage, the description must explain parameters, and it does so for most: chain_pitch_mm vs chain_number, strand scaling, and k_r override semantics. However, power_w's role is only implied through 'Powers in W' and the output field power_sf?, and the formula symbols N1/n1/P are not explicitly mapped to teeth_small/speed_rpm/pitch.

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 opens with a specific verb-resource statement: 'Rate an ANSI roller-chain drive (ASME B29.1)'. It clearly distinguishes this from transmission siblings like belt_drive and gear_rating by naming the exact standard and component type.

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 gives a clear use context: rating roller-chain drives under ASME B29.1, and explains when to supply chain_pitch_mm versus chain_number and when k_r is needed for a chain outside the ANSI table. It does not explicitly state exclusions or name alternative tools for non-chain drives, so it stops short of a 5.

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