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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety profile is covered. The description adds a genuine behavioral caveat beyond annotations — that the output is a length figure, not a signal-reach guarantee. It says nothing about rounding, units of the result, allowed edge cases, or why two storefronts exist.

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?

Three short sentences, front-loaded with the action and immediately followed by input semantics and the output caveat. No filler; the only mild vagueness is the word 'sections', which is not a schema term.

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, annotation-light, no-output-schema tool the description is partially adequate: it names the return value and the general input families. It is not complete enough to call confidently, since required 'storefront', the large 'signal' enum, and 'quantity' are unexplained and nothing describes result precision or units.

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% across 11 parameters, so the description must carry the burden. It loosely groups parameters into semantic buckets ('sections in metres, loops, installation route and allowance') that map to horizontal/drop/rise/travel, loopFrom/loopTo, routing and wastePercent, which is real added value. However, it never explains storefront (required, enum eu/pl), the 24-value signal enum, quantity, or which of 'sections' means horizontal vs drop vs rise.

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 states a concrete purpose: run the native Modulit cable calculator and return required cable length from sections in metres, loops, routing and allowance. It also clarifies the output is a length estimate, not a signal-integrity certification. Sibling tools (product search, power config) are unrelated, so explicit differentiation is unnecessary, but the verb is implied rather than stated as 'calculate cable length'.

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 implicitly defines the use case (estimating cable runs) and gives one useful scope exclusion: the result is not a certification of signal reach. There is no statement of when to prefer this over manual estimation or other tools, no mention of required prerequisites, and no guidance on storefront selection despite 'storefront' being required.

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