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

Annotations already indicate this is not read-only and can operate on an open world, so the description's main addition is 'automatically' and 'standing mandate,' which signal an autonomous financial action. It does not disclose further behavioral traits such as side effects, irreversibility, or auth requirements, but it does not contradict 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?

The description is a single, front-loaded sentence with no filler words. Every phrase adds some information about the tool's purpose and execution context.

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?

Despite a high-stakes purchase execution and a complex schema of nested objects, there is no output schema, no parameter guidance, no return-value description, and no mention of required preparation such as obtaining a signed offer or validating the mandate. The description is far too minimal for an agent to safely invoke this tool 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 description coverage is 0%, and all three parameters are opaque objects with additionalProperties: true. The description does not explain what belongs in offer, agentRequest, or paymentPayload, nor how they relate to a signed purchase or standing mandate. This leaves an agent without enough information to construct a valid call.

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 states a specific verb ('execute') and resource ('signed agent purchase'), and clarifies that execution happens automatically within a standing mandate. This distinguishes it from sibling tools like issue_signed_offer or register_owner_mandate.

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 phrase 'within a standing mandate' gives clear context for when this tool should be used: after a mandate exists and a signed purchase is ready. It does not explicitly name alternatives or exclusions, but the context is strong enough for an agent to route correctly.

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