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

Annotations already establish readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description does add genuine behavioral context: results include a 'real' checkout URL, a required payload schema, and availability that is conditional on tax gating. It does not say what happens when tax gating blocks availability or whether the returned URL expires.

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?

A single front-loaded sentence that lists the returned artifacts without filler. It is dense with domain jargon (MPP, SPT, tax-gated) but nothing in it is redundant, and the most important payload, the checkout URL, leads the list.

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 one-parameter read tool with no output schema, describing the shape of the response (URL, schema, availability, retrieval steps) is largely sufficient. The gap is the undocumented offer_id and the absence of any statement about what to do when tax gating makes the offer unavailable.

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?

There is one required parameter, offer_id, with 0% schema description coverage, so the description must carry the meaning of that parameter. It never mentions offer_id, so an agent cannot tell from the text whether the instructions are scoped to a specific offer or whether the identifier format matters.

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 names a specific retrieval action and enumerates exactly what comes back: a Stripe MPP SPT checkout URL, the required JSON schema, tax-gated availability, and order retrieval steps. That is far more specific than a restated title, though it never explicitly contrasts itself with marketplace_prepare_mpp_checkout, which an agent could plausibly confuse it with.

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?

Usage is only implied by the name and the 'purchase instructions' framing, which suggests consulting this before an MPP checkout. There is no statement of when to call it versus marketplace_prepare_mpp_checkout, no prerequisite ordering, and no exclusions.

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