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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld behavior. The description adds meaningful context beyond annotations: it excludes expired and single-use codes, explains per-row verification provenance (seen_on_brand_homepage vs third_party_unverified), notes freshness stamping, and describes credit billing with no charge when no data is returned.

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 description is front-loaded with the core purpose and return fields, followed by filtering, provenance, freshness, and billing details. It is dense but structured, though the billing parenthetical is slightly tangential for an agent selecting the tool.

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?

No output schema is present, so the description usefully names return fields (code, discount, terms, valid_until) and explains provenance and freshness. Annotations cover safety and idempotency, and the single parameter is fully documented by the schema; only minor domain-format and result-shape details are absent.

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% for the single domain parameter, already described as "eCommerce domain". The description does not add format details, examples, or semantics 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 specific resource and scope: active promotions/discount codes for a brand, with named fields (code, discount, terms, valid_until). It implicitly distinguishes itself from sibling analytics tools like get_discount_frequency_and_depth by focusing on live coupon codes rather than discount trends, though it does not explicitly name alternatives.

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?

Usage is implied by "Active promotions/discount codes for a brand" and the exclusion of expired/single-use offers, but there is no explicit when-to-use guidance, no mention of when not to use it, and no named sibling alternative such as get_discount_frequency_and_depth or get_most_discounted_products.

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