contact_setup

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

No annotations, so the description carries the full burden. It discloses the mutation to solver nonlinear state, the master/slave ordering of pairs, the frictionless default, and the returned structure. It does not state required permissions or side effects on existing analysis state, leaving a small 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?

Front-loads purpose well but packs parameter explanations, sequencing, a gate heuristic, and a return shape into one dense block. The gate paragraph is arguably tangential to the tool's call contract and adds length without helping invocation correctness.

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 6-param, no-annotation, no-output-schema tool it covers purpose, ordering, most parameter semantics, and return shape. Missing analysis param description and permission/side-effect disclosure, but the critical pieces for correct invocation are present.

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%, so the description must compensate, and it does: face_pairs is documented as a list of {a:{handle,tag|face}, b:{handle,tag|face}} master/slave pairs, friction as Coulomb coefficient, slope as penalty stiffness, nonlinear default True, name implied. It omits the 'analysis' parameter semantics.

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 ('Set up surface-to-surface contact between face pairs for a CalculiX solve and flip the solver to nonlinear'), and distinguishes from siblings by noting it promotes existing CCX flags rather than adding a new solver. An agent can tell it apart from hertz_contact and fem_add_constraint.

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?

Explicit sequencing guidance: 'Run fem_run + fem_results after' and a gate instruction relative to a bonded reference on the same mesh. Missing explicit when-not-to-use and named alternatives among siblings, but the context is clear.

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