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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context about return values and the downstream signing/purchase flow, though it does not discuss permissions or failure cases.

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 concise sentences with no wasted text. The purpose and pre-purchase requirement are front-loaded, followed by the key return behavior and downstream use.

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?

The tool is simple and the description covers the essential workflow: check requirements, learn free versus paid, and pass the x402 object to purchase_asset. Annotations cover safety and an output schema exists, so no further return-format explanation is required.

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 100%, and the single uploadId parameter is already documented in the schema. The description confirms that the tool operates on a marketplace asset but adds no further syntax or format detail beyond that baseline.

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: retrieve payment requirements for a marketplace asset. It clearly distinguishes this pre-purchase check from purchase_asset by describing the returned free/paid status and x402 payment requirements object.

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?

Explicitly says to call this before purchasing and that the returned x402 object must be passed to purchase_asset. This gives clear workflow context, though it does not state exclusions or alternatives beyond that primary path.

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