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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile needs no restating; the description instead adds real behavioural context: the outputs are planning values rather than a manufacturer guarantee, several physical/safety checks are explicitly not performed, and the response contains a shareable link opening the calculation on planelec.be. The remaining gap is that it doesn't describe accuracy tolerances or what happens when explicit fields conflict with a preset (the schema, not the description, carries the override rule).

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 purpose and the required inputs are front-loaded, followed by the optional parameter list and then the scope caveats, which is a sensible order and wastes little. The middle sentence is a dense enumeration that partially restates the schema, so it is slightly longer than strictly necessary, but every clause carries information.

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 14-parameter calculation tool with an output schema present, the description covers the essential contract: inputs and alternatives (preset vs. datasheet), optional planning parameters, the limits of the advice, and the fact that a shareable result link is returned. Nothing an agent needs in order to call it correctly is missing.

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 100%, so the baseline is 3, but the description adds genuine framing by grouping the inputs into a required core (length, preset-or-datasheet values) and an optional planning tier (cut unit, max length per feed, feeds, reserve, cable length/material/cross-section, voltage-drop limit), which helps an agent decide which fields matter. It adds no numeric defaults or units beyond what the schema states.

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 opens with a precise verb plus an enumeration of outputs (power, current total and per channel, feed points, PSU size, feed cable) for a well-defined resource: analogue LED strips at 5/12/24/48 V DC across the listed colour modes. This is unmistakably distinct from siblings such as size_cable_arei or check_inverter_c10_26, so an agent can route to it without opening the 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?

It states the minimum invocation contract clearly (length in metres plus either a preset or datasheet values) and flags which inputs are optional, which is the practical when-to-use guidance for this tool. It does not name an alternative tool or explicitly say when not to use it, but it does bound the use case by declaring that current-carrying capacity, heat and AREI/RGIE rules are out of scope.

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