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

Annotations already declare readOnlyHint=true, destructiveHint=false and a closed world, so safety is covered and the description isn't obliged to restate it. It adds genuinely useful behavior beyond that: each row carries openPoCount (POs not fully received) and itemCount (linked catalogue items), which are the kind of return-shape details annotations can't express.

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 core purpose is front-loaded, then the id-resolution role, then the sibling contrast — a sensible ordering. It is somewhat dense with em-dash asides and parenthetical clarifications, but each sentence carries distinct information rather than filler.

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 usefully compensates by naming the per-row fields (openPoCount, itemCount), and it covers purpose, use cases, id semantics, and the alternative tool. Pagination mechanics are left entirely to the schema, which is acceptable but the only real 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% (page, search, pageSize all documented in-schema), so the baseline is 3. The description only loosely touches the search parameter by framing the name-to-id lookup; it adds no syntax, matching, or pagination detail beyond what the schema already provides.

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 specific verb and resource ('The businesses this merchant BUYS stock from') and immediately frames the domain scope via 'Purchasing → Suppliers'. It explicitly contrasts itself with get_products ('the buying side' vs 'what the merchant SELLS'), so an agent can separate it from the product-listing sibling without opening a schema.

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?

Gives concrete trigger questions ('who do I order from', 'which suppliers have open orders') and a critical routing rule: this is the way to convert a supplier name into an id, since purchase-order and item-linking tools take ids only. It also names get_products as the alternative for the selling side, covering both when-to-use and when-not.

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