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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds substantial context beyond them: the returned pay_url serves a real HTTP 402 challenge, the amount is server-computed and must never be recomputed or estimated, and the URL must be handed to the pay tool rather than fetched or decoded. That is the kind of operational detail that prevents a costly misuse.

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?

Front-loaded with the concrete outcome and the primary exclusion, and the priority rule is stated before the mechanics. Minor redundancy: the 'hand it over, never fetch or decode it yourself' instruction appears effectively twice in the final two sentences.

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-only link-generation tool with an output schema and clear annotations, nothing an agent needs is missing: precondition, priority, price authority, and next action after receiving the URL are all present.

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 coverage is 100% and the single parameter already documents the 5-100000 range and the $0.50 minimum, so the schema does the heavy lifting. The description adds pricing semantics ($0.10/token) and the rule that the price is authoritative from the server, which is meaning beyond the schema but not parameter-specific detail.

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 and resource: minting a real, payable MPP URL to top up AI Tokens, including the unit price. It explicitly distinguishes itself from sibling buy_ai_tokens's own payment flow, so an agent can route correctly without opening either schema.

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?

Gives an explicit precondition (only when an MPP-native agent's tools like link-cli's mpp_pay are present in the session), an explicit priority ordering (priority 2, only after buy_ai_tokens's in-band flow is not viable), and an explicit exclusion plus the note that no checkout-link fallback exists. When/when-not/alternatives are all covered.

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