Fund SAP Subscription

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

Annotations already indicate a write operation (readOnlyHint=false) and non-destructive (destructiveHint=false). The description adds valuable context about requiring signer mode and policy approval, and places the tool within the payment and settlement flow, going beyond the annotations.

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?

Description is three short sentences: first clearly states purpose, second adds context, third states prerequisites. No wasted words, front-loaded with essential information.

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?

Given the tool has an output schema, the description does not need to explain return values. It covers purpose, usage context, and prerequisites. Could be slightly more explicit about the effect (e.g., funds added to subscription) but is largely complete.

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 detailed parameter descriptions. The tool description does not add new parameter-level insights beyond the schema, but it provides overall context. Baseline 3 is appropriate.

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?

Description clearly states 'Fund a recurring subscription' with specific verb and resource. It distinguishes from sibling tools like sap_create_subscription or sap_cancel_subscription by focusing on the funding action, and provides SAP MCP context to situate the tool in the payment and settlement flow.

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?

Description advises to 'Estimate or fetch state before creating escrows or settling calls' and notes prerequisites (enabled signer mode, MCP policy approval). It gives clear context for when to use, though it does not explicitly mention alternative tools or when not to use.

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