whoami

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

No annotations are provided, so the description must disclose behavior. It correctly indicates this is a read-only operation (discover) and lists the returned items. No side effects are mentioned, which is appropriate for a query tool. Sufficient for a zero-parameter 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, no wasted words. The example call is immediately useful. Front-loaded with the purpose, then the exact invocation. Excellent conciseness.

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?

Although there is no output schema, the description explicitly lists what the tool returns (wallet, chain, factory address, spending limits), providing adequate information for an agent to understand the result. For a simple query tool, this is complete enough.

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, no additional semantics are needed. The description includes a JSON example showing the empty args, which adds clarity. Baseline 4 is appropriate since schema coverage is 100% and description adds value through the example.

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 tool's purpose: 'Discover the current wallet, chain, factory address, and spending limits.' It uses specific verbs and nouns, and distinguishes itself from sibling tools which are all action-oriented (e.g., erc20_create_payment, raise_dispute).

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?

Provides an explicit call example, guiding the agent on how to invoke the tool correctly. While it doesn't explicitly contrast with siblings, the purpose is distinct enough that an agent can infer when to use this tool (to get identity info) vs alternatives.

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