Prepare Hosted x402 Challenge

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

Annotations already declare readOnlyHint=true, and the description adds key behavioral details: it is free, calls the target tool without payment, and returns a challenge without signing. It doesn't mention any side effects, but given readOnlyHint, the description is consistent and adds value.

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?

The description is concise with three sentences, front-loads the key information, and avoids unnecessary detail.

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 read-only helper tool with annotations and an output schema, the description sufficiently covers purpose, usage scenarios, and behavioral context, leaving no critical gaps.

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% with individual parameter descriptions. The tool description provides context for the parameters as a whole (e.g., initializing hosted SAP MCP and calling a paid tool), but does not add meaning beyond what the schema already provides, meeting the baseline of 3.

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 clearly states it is a low-level free helper that initializes hosted SAP MCP, calls a target paid tool without payment, and returns the parsed x402 challenge without signing. It distinguishes itself from sibling tools like sap_payments_call_paid_tool by specifying its limited use.

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 tells when to use this tool ('for inspection, policy review, or custom x402 clients') and advises that normal agents should prefer sap_payments_call_paid_tool, providing clear guidance.

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