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

With no annotations, the description carries the full burden but does add two important behavioral facts: the tool returns a continue_url for the buyer and does not charge anything. It still omits auth requirements, session expiration, idempotency behavior, and failure modes.

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, front-loaded with the core purpose and followed by the return value and key caveat. No wasted words, though the final sentence could be folded more smoothly into the previous one.

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 creation tool with no output schema and no annotations, the description covers the core action and return value. It remains incomplete on parameter meanings and on when to use this tool instead of siblings like get_checkout.

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 0%, so the description must explain the two parameters. It only implies offer_id via 'one offer' and says nothing about the allowed enum values or the quantity parameter's default, minimum, or maximum.

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 + resource ('Start a purchase of one offer') and distinguishes itself from get_checkout by being the creation action. However, it does not name or compare against any sibling tool, so the differentiation is implied rather than explicit.

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 explains the post-call flow (send the buyer to continue_url) but gives no guidance on when to choose this tool versus get_checkout, list_products, or any alternative. No when-not or prerequisite context is provided.

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