steward_payment_format

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

With no annotations, the description carries the burden and does well: 'Free, read-only — never signs or spends' rules out cost and custody side effects, and the byte-exact/prevention framing signals it is a static reference rather than an action. It stops short of describing the response shape, but for a no-side-effect guide the safety profile is covered.

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 tight clauses, front-loaded with the deliverable, then the trigger condition, then the safety guarantee. No filler and nothing repeated from structured fields.

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 zero-parameter reference tool with no output schema, the description gives enough: what it returns (a byte-exact header guide), when to invoke it, and its non-destructive nature. Only a hint about the returned artifact's format would improve it further.

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 tool takes zero parameters, so the baseline is 4 and there is nothing for the description to clarify. The absence of any argument-format caveat is appropriate here, since none exist.

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 deliverable (a byte-exact guide for constructing an X-PAYMENT header) with precise scope (x402 v1, EVM, USDC on Base). It is unmistakably distinct from steward_purchase_instructions and every other sibling, which are all operational rather than reference tools.

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 when to call it ('BEFORE an agent's first self-paid purchase via steward_purchase_instructions') and names the sibling that triggers the need. It even supplies the motivation — most failed payments are header-format errors — so the agent knows the cost of skipping it.

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