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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, and the description is consistent with that. It goes further by disclosing the pricing algorithm (second-most-expensive add-on 25% off with 2+, then 10% early-sign discount) and the return shape (line items, discounts, total ex VAT, no-discount comparison, budget fit), which are real behavioral facts an agent cannot get from 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?

The tool's purpose and the discount logic are front-loaded before the return-value clause, and every clause carries information. The single dense sentence with stacked em-dash asides is readable but heavier than necessary; a small split would improve scanning without losing content.

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?

With no output schema, the description fully carries the burden and delivers: it enumerates the returned components (line items, discounts, total ex VAT, comparison total, budget verdict) and explains the pricing rules that produce them. All five parameters are documented and the read-only nature is covered by annotations, leaving nothing an agent needs 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 description coverage is 100%, so every parameter is already documented in the schema (sign_date deciding the early-sign discount, budget_eur triggering the fit check, addons listing valid values). The description restates the discount interaction but adds no syntax or format detail beyond what the schema provides, 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?

The description states a precise verb+resource (quote a partnership) and spells out the exact scope: package plus optional add-ons with published discount rules applied. It is unambiguous about what the tool computes, but it does not name or distinguish itself from nearby siblings such as compare_packages, get_package, or request_partnership_offer, so the reader must infer the boundary.

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?

"Always use this instead of adding up prices yourself" is an explicit directive on when to reach for this tool, which is stronger than typical guidance. However, it only rules out manual arithmetic, not alternative tools; there is no statement about when a sibling like compare_packages or request_partnership_offer would be preferable.

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