Transmission line input impedance

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description goes further by disclosing the full return set (Γ at load and input, electrical/physical length, guided wavelength, distances to first voltage max/min) and noting it handles lossy or lossless lines — genuine behavioral context beyond the annotations.

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 operation and its formula, then returns, then use cases — a sensible ordering. Three dense sentences with no filler, though the inline formula is somewhat heavy and the return list could be trimmed.

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 an 11-parameter tool with no output schema, the description usefully enumerates what comes back and clarifies the length/loss/unit model. Combined with 100% schema coverage, an agent has what it needs; only the absence of explicit prerequisites (e.g. frequency required for physical lengths is left to the schema) keeps it from a 5.

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 100% and every parameter (z0, load, length, eps_eff, velocity_factor, etc.) is already documented in the schema, including unit formats and defaults. The description restates the formula and unit conventions but adds little semantic detail the schema lacks, so the baseline of 3 applies.

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 precise verb+resource — input impedance of a transmission line terminated in a load — and even supplies the governing equation. This is unmistakably distinct from siblings like impedance_convert (a pure impedance transform) or the design_* matching tools, which an agent can tell apart without opening schemas.

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 concrete usage context: 'Use for coax/microstrip/λ/4/λ/2 line questions and where-is-the-voltage-minimum problems.' That's clear routing, but it names no alternative tool and states no when-not-to-use condition, 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.