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

No annotations provided, so description carries full burden. Describes return type (agent capabilities only, no credentials) and implies a read-only lookup. Lacks details on error handling, idempotency, or rate limits, but adequate for a simple discovery tool.

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?

Two sentences plus an example, no redundant information. Front-loaded with the main purpose. Highly concise and well-structured.

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 simplicity (one required param, no nested objects, no output schema) and sibling context, the description is mostly complete. It explains the tool's role and usage but could benefit from clarifying what 'agent capabilities' entails or typical error cases.

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 covers the single parameter fully (100% coverage). Description adds an example and format clarification but does not significantly extend beyond schema. 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 it retrieves the AP2/A2A agent-commerce block for a pay: address, uses an analogy ('DNS of Money equivalent'), and distinguishes itself from siblings by explicitly stating no payment credentials are returned.

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 states when to use: 'during agent discovery before initiating a mandate flow'. Provides an example. Does not explicitly list alternatives but sibling names and context imply differentiation.

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