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

Annotations cover read-only and open-world status, and the description adds genuinely non-obvious context: no account or key needed, a $0.50 minimum for 10 lookups, guest tokens defaulting to 24 hours with up to 720 hours requestable before paying. It stops short of describing what a call yields or any rate/return behavior, but the auth and cost disclosure is substantive.

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 with no filler, but the emphasis is skewed toward pricing and token lifetimes rather than the operation itself. The most decision-relevant information for an agent (what the catalog contains) is absent while commercial detail occupies most of the text.

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 parameters and no output schema, the description must explain what a call returns, and it does not — an agent cannot tell whether it gets a list of MPP payment options, endpoints, or plans. Auth and cost are covered, but the core result contract is missing.

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 input schema has zero parameters, so there is no parameter meaning for the description to carry. Baseline of 4 applies; the description adds no misleading parameter claims.

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 says "Discover Stripe card MPP payments," which restates the name's notion of a catalog without specifying what an invocation actually returns or lists. No concrete verb-plus-resource operation is stated, and nothing distinguishes it from siblings such as mpp-data or mpp-purchase.

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 only conditional guidance is negative framing ("without an existing BuiltWith account or API key") and a note that "Lists require a plan." There is no statement of when to call this versus mpp-data, mpp-purchase, or the payment-* tools, and no prerequisite sequencing beyond the token hint.

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