EM Field

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

Annotations already provide readOnlyHint, so the main behavioral disclosure is whether this is analytic or numerical. The description explicitly says 'NO solver' and 'Exact magnetostatic field', adding the key deterministic and non-iterative behavior. It also discloses the return units and structure with {b_t, b_mt, …}. Minor gaps remain for null-input handling, but the annotations lower the burden here.

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 compact and front-loaded: it opens with the tool's exact purpose and non-solver nature, then gives formulas and the return signature. Every sentence carries useful information and there is no filler or redundant repetition of schema defaults.

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 is essentially complete for a simple read-only analytic field calculator: it covers both supported kinds, maps parameters to formulas, gives units, and states the output format. It stops short of explicitly saying which parameters are ignored for each kind or what happens when required inputs are null, but those are minor given the formula-level guidance.

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 add meaning to parameters. It successfully does: kind is explained as wire or solenoid, distance_mm appears in the wire formula, turns_per_m in the solenoid formula, and mu_r and current_a are directly used in the physical expressions. Every parameter has a clear physical role.

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 clearly states that this tool computes an exact magnetostatic field for two canonical sources, wire and solenoid, and prefaces with 'NO solver' to distance it from numerical simulation tools. It gives a specific verb and resource and readily distinguishes itself from solver-type siblings.

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 clearly defines the two supported cases, showing when to use the wire formula with distance_mm versus the solenoid formula with turns_per_m. The 'NO solver' note gives a strong selection cue against numerical solver alternatives, though it does not explicitly name sibling tools or list exclusions.

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