em_skin_depth

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

No annotations are provided, so the description carries the full burden; it discloses the closed-form model, the decay law, the conductivity source options, and the exact return keys. It stops short of stating precedence between conductivity_s_m and conductor, or how invalid/unsupported inputs fail.

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 the core purpose and formula in the first clause, then covers the physics rationale and inputs. The remaining sentences all earn their place, though the formula and physics aside make it denser than a terse one-liner.

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 pure-computation tool with no output schema and no annotations, the description supplies the return field list, input sources, and method, which is nearly sufficient. Remaining gaps are minor: parameter precedence and error behavior are untreated.

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, and it largely does: it names conductivity_s_m explicitly, enumerates the valid conductor names, and ties mu_r and frequency_hz to terms in the formula. It omits mu_r's default and which of conductivity_s_m vs conductor wins when both are supplied.

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?

Uses a specific verb+resource ('Exact AC skin depth') and immediately disambiguates from the solver-based siblings in this family (em_field, em_induction_*, em_conduction_submit) with the parenthetical 'NO solver'. The embedded formula states exactly what is computed, so an agent can tell it apart without opening a schema.

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 'NO solver' framing implies this is the lightweight analytic path versus the submit-style siblings, and the ~1.5·δ note hints at a use case (induction heating depth coverage). However, it never explicitly states when to choose this over em_induction_submit or em_dc_resistance, so usage is implied rather than spelled out.

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