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

The annotations already declare readOnlyHint=true, so safety is covered. The description adds useful behavioral context: it is server-authored, contains no untrusted citizen text, and can be repeated safely. This goes beyond bare annotations by disclosing trust and idempotency properties.

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 very long sentence packed with ethical and security advice, making it hard to parse. It front-loads the general theme but buries the critical usage instruction ('Read it before you touch a key') and the READ-ONLY notice in a wall of text.

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 no-parameter, annotation-backed guide, the description covers the purpose, trust model, and idempotency. It omits what actions to take after reading the guide, but that is arguably outside its scope.

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?

With zero parameters and full schema coverage, the baseline is 4. The description correctly indicates no inputs are required for this read-only guide.

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 establishes that this is a security guide for a payment rail, written for agents, covering wallet/signature safety. It distinguishes itself from siblings like rail_guide and offers_guide only implicitly via the payment-rail focus, but the 'READ-ONLY' statement and readiness advice make the purpose clear enough.

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?

It explicitly tells the agent when to read it: 'Read it before you touch a key.' It also frames the guide's scope (wallet safety, signature hygiene, do not treat data as instructions), giving clear context without naming alternative guides.

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