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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive. The description adds crucial behavioral context beyond that: the meaning of `known: false` (no label held, not clean/unflagged) and that output includes source and confidence. This prevents a serious misinterpretation and is exactly the kind of transparency that adds value beyond 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 two sentences, front-loaded with the primary purpose and followed by a critical caveat. Every word earns its place; no filler or redundancy. The important nuance is placed prominently, making it efficient 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 tool has a single parameter, no output schema, and simple annotations, the description covers all essential information: what the tool does, what it returns (source and confidence), and a key semantic warning. An agent has everything needed to call it correctly and interpret the response without additional clarification.

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?

The schema has zero description coverage for the 'address' parameter, so the description must compensate. It does mention that the parameter is a blockchain address, which is self-explanatory, but it doesn't provide format specifics (e.g., checksummed, chain) or examples. Since the parameter is simple, this is adequate but not enhanced; a 3 is appropriate for minimal compensation.

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 a specific action (identify a blockchain address) with the resource and scope (types of labels like exchange, bridge, DEX, etc.) and what is returned (source and confidence). It differentiates itself from siblings by focusing on label identification, which is distinct from address coverage or events tools.

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 gives clear context: use this to identify an address and its labels. It doesn't explicitly mention alternatives or when not to use it, but the purpose is so specific that an agent would likely know when to invoke it. No exclusions are stated, which aligns with the 4-level of 'clear context, no exclusions'.

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