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

Annotations already mark the tool as read-only, idempotent, and open-world, so the core behavioral context is covered. The description adds useful specificity about what is not performed (create/fund/verify/start), but it does not add detail about response format, auth requirements, or offer selection. No contradiction with annotations.

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?

Two tight sentences with the primary behavior front-loaded and the negative scope stated in a single clear sentence. Every word earns its place; there is no fluff or repetition of schema content.

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 simple two-parameter read-only tool with rich annotations, the description covers the core intent and explicitly rules out side effects. It is slightly incomplete in not pointing to how an offer is selected or that human authorization must be supplied, though the schema already documents the latter.

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?

The schema fully documents human_authorized_to_fund, and the description's 'selected offer' gives minimal but real meaning to offer_id. It does not explain the two cryptic offer_id enum values or connect them to a prior list/selection step, so the description only partially compensates for the schema's missing offer_id documentation.

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 clear verb ('Return') and resource ('machine-readable purchase-intent schema and API endpoint') for a selected offer. The explicit negative scope ('does not create, fund, verify, or start an order') clearly distinguishes it from action-oriented purchase tools and from the sibling tools.

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 description implies it should be used when an offer is already selected and only the schema/endpoint is needed, and it warns against expecting side effects. However, it does not name alternatives or state when not to use it relative to siblings like qualify_task or list_offers.

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