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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety needs little restating. The description still adds real behavior beyond them: it performs availability and stock validation, produces a link rather than an order, and explicitly neither places orders nor reserves inventory — key facts for an agent deciding whether this really completes a purchase.

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 plus a closing constraint, all front-loaded: validation, returned link, customer flow, then the negative guarantee. No filler or repetition of the schema.

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 should say more about what comes back — only "a link" is stated, with no mention of the response shape or what happens when an item fails the availability check. The behavioral picture of the customer flow is complete, but the failure and return-value side is thin.

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 50%: store is fully documented with its codes, and sku is documented as a variant SKU. The description usefully adds provenance for SKUs (they come from get_product), but says nothing about qty semantics or the item-count limits, so it only partly compensates for the coverage gap.

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 and outcome: it validates that items are sold in the store and in stock, then returns a customer-facing link. It also distinguishes itself from the sibling get_product, which is named as the source of the SKUs it expects.

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?

"use variant skus from get_product" explicitly routes the agent to the sibling for input preparation, and "this does not place an order or reserve stock" rules out a plausible but wrong expectation. There is no alternative tool for the same job, so the lack of a named 'instead use X' case is acceptable.

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