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

Annotations already declare readOnly/idempotent/non-destructive/non-open-world, so the safety bar is lower, yet the description still adds real context: prices are net, German VAT of 19% is applied at checkout, and the values come from published Offer metadata. The explicit denial of filing/payment/certificate handling reinforces the read-only contract rather than contradicting it.

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 sentences, purpose front-loaded, and the VAT/source details come before the defensive negatives. The final sentence's list of negations is the longest element and partly restates what the annotations already signal, but it is not padding.

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 zero-parameter, read-only tool with no output schema, the description covers scope, pricing semantics (net + VAT), authoritative source, and prohibited side effects. The one remaining gap is that it never indicates the shape of what is returned (e.g., per-product or per-submission price structure), which the agent must infer.

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?

The tool takes zero parameters, so per the rubric the baseline is 4; there is no argument surface for the description to explain. Nothing in the description misleads about inputs.

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?

Names a specific verb+resource ('current net prices per submission') and even discloses the data source ('the site's published Offer metadata'), so the agent knows exactly what is retrieved. It does not name or differentiate itself from the siblings ebf_get_products or ebf_check_eligibility, and its claim to also answer legal-form/size-class/year scope questions overlaps with what ebf_check_eligibility appears to do.

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 clear when-not guidance: 'prepares nothing, never files, never takes payment, and never accepts an ELSTER certificate or PIN', which rules out a class of mistaken invocations. It stops short of explicitly routing to alternatives ('use ebf_get_products for X, ebf_check_eligibility for Y'), so the sibling boundary is left to inference.

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