steward_purchase_instructions

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

With no annotations, the description carries the full burden and does well: it discloses that the call is free and read-only, that it reads the 402 response but never pays it, and that data is parsed live. It stops short of covering error cases, rate limits, or what the agent must have configured wallet-side.

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 core verb+resource before any caveats, and every clause provides actionable information. The dash-delimited clause and final sentence make it slightly denser than ideal, but nothing is filler.

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?

There is no output schema, but the description compensates by listing the fields returned, and it covers the prerequisite and the two payment paths. An agent has everything it needs to invoke this correctly.

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 sku parameter is already documented as 'exactly as returned by steward_catalog'. The description reinforces the same constraint but adds no syntax, format, or edge-case detail beyond the schema, so the baseline 3 applies.

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 resource and enumerates the exact outputs (pay-to address, amount, asset, network, facilitator), so the agent knows precisely what it gets back. It distinguishes itself from steward_catalog by being the payment-requirements step rather than the discovery step.

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 prerequisite ('Find the sku with steward_catalog first'), explains the payment flow ('agent pays with its own x402/EVM wallet'), and names the alternative path where no manual payment step is needed when using the server's paid tools.

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