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

Annotations already mark it read-only and non-destructive; the description adds the useful behavioral facts that it is a dry-run, returns a rules evaluation, and never writes. This goes beyond the structured fields by clarifying the no-side-effect nature and the result shape.

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, all informative: purpose, output, and side-effect profile. The critical 'BEFORE submitting' guidance is front-loaded and no filler is present.

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 7-parameter tool with no output schema and only 29% parameter documentation, the description is too thin: it does not define required inputs like slug or offer format, nor the shape of the returned rules evaluation. The safety profile is covered by annotations, but call preparation is not.

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 very low (29%) and the description does not compensate: only 'negotiation proposal' loosely maps to the offer parameter, while slug, query, budget, timeline, and requestedTerms remain unexplained. It adds only minimal context beyond the schema.

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?

Uses the specific verb 'dry-run' plus a precise resource ('a negotiation proposal') and a specific rule context ('seller's rules'), clearly distinguishing this from the checkout-validation sibling. It states exactly what the tool evaluates, not merely repeating the title.

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?

Explicitly says to use it BEFORE submitting a negotiation proposal, which is a clear invocation context. It does not name sibling alternatives or state when not to use it, though the negotiation scope already separates it from validate_checkout.

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