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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds important context the name 'buy_reach' obscures: it merely builds a cart and returns a quote, not a purchase. It also discloses that the combo discount is applied automatically and the quote states whether the cart fits budget. Return-format detail is thin, but the output schema covers that.

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 triggering question and the core behavior in two sentences with no filler. It loses a point because the ten-item enumeration duplicates the oneoff_ids enum already present in the schema, lengthening the sentence without adding new 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?

With an output schema present, the return shape need not be described, and annotations plus full schema coverage handle safety and parameters. The description supplies the missing conceptual framing (cart → combo discount → signable quote) and the audience reach figure, leaving no agent-facing gap.

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 context, budget_eur, and oneoff_ids are fully documented in the schema itself. The description restates the ten item names that already appear in the oneoff_ids schema, adding no syntax, format, or defaulting detail beyond what is structured. Baseline 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 concrete verb+resource ('Builds a cart from ELC's ten published one-off reach items') and enumerates exactly what the cart can contain, so an agent can immediately tell it produces a priced quote rather than performing assessment work. This clearly separates it from every sibling (assess_*, benchmark_*, evaluate_*, build_partnership_business_case).

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?

Frames the triggering question ('how do we get in front of 3,300+ CEE engineering leaders, and what does it cost?') and states the output is 'a decision-ready quote a human can sign,' implying it is for cost/scoping rather than readiness evaluation. No explicit when-not-to-use or named alternative is given, 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.