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

The description states it 'reads escrow/pricing when available,' implying read-like behavior, but annotations set readOnlyHint to false, creating slight ambiguity. No explicit mention of side effects or data modification. With annotations already indicating non-destructive and non-read-only, the description adds limited behavioral context beyond execution guidance.

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 a single paragraph followed by a separate block of execution guidance that repeats information from the input schema. The first sentence is clear, but the rest could be more compact. Some boilerplate ('SAP MCP context', 'Routing') adds length without unique value per sentence.

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 5 parameters, all well-described in schema, and the presence of an output schema, the description covers the essential usage flow and execution constraints. It mentions pricing and routing, which is helpful but slightly redundant with the schema's own description. Nearly complete for the tool's complexity.

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%, so the schema already documents each parameter. The description adds context like 'supports optional volume curve overrides,' but this is also reflected in the schema descriptions. 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?

The description clearly states the verb ('Estimate') and resource ('cost for a number of calls') with explicit reference to the SDK method (X402Registry.estimateCost). It distinguishes well from sibling sap_x402_* tools that handle building headers, fetching escrow, settling, etc.

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?

The description provides explicit guidance on when to use: 'Estimate or fetch state before creating escrows or settling calls.' It also notes prerequisites for write operations (enabled signer mode and MCP policy approval), effectively excluding this tool from write contexts.

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