jumbo_get_promo_digest

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

With no annotations, the description carries the full burden, and it explicitly declares 'Read-only: no writes, no basket, no checkout, no order or payment operations' — a genuinely useful safety disclosure. It stops short of mentioning auth requirements (there is a jumbo_login sibling), rate limits, or behavior when no receipts exist.

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, front-loaded with the user-facing question, then the mechanism, then the safety profile. No restatement of the tool name and no filler; every clause carries 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?

There is no output schema, but the description enumerates the returned fields (was/now price, discount, promo type, validity window, unit price), which compensates well. Combined with the read-only disclosure, the picture is nearly complete, with only auth/precondition detail 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 coverage is 100%, so the baseline is 3, but the description adds conceptual meaning: 'mines recent receipts' clarifies what days governs and 'purchase frequency' clarifies what min_times governs. It does not explain the category substring matching or how limit interacts with resolution of frequent items, so it stays just above baseline.

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 concrete verb chain (mine receipts → resolve to assortment product → report offers) against a named resource, and it is framed by the exact user question it answers. It is clearly distinguishable from siblings like jumbo_get_product_recommendations and jumbo_search_products, which do not combine purchase history with current promotions.

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?

The 'of the things I actually buy, what is on offer right now?' framing gives an agent a clear condition for selecting this tool over a generic product search. However, it never names an alternative tool or states when NOT to use it (e.g. for browsing promotions on items you have never bought).

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