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

While the readOnlyHint annotation already indicates safety, the description adds meaningful behavioral context: the tool is the canonical source used by the rails themselves, requires no key or payment, and the ECOWEALTH/EWP confusion has previously broken a live session. This goes beyond the annotations without contradicting them.

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 compact and front-loaded with purpose, followed by critical usage guidance and a real-world warning. Every sentence earns its place, and there is no filler or repetition of schema details.

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 single-optional-parameter, read-only registry lookup with an output schema, the description is complete. It tells the agent why the tool exists, when to call it, what danger to avoid, and that no authentication is needed. Nothing essential is missing.

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 already fully documents the only parameter, `symbol`, with an example. The description does not introduce new parameter-level details beyond the schema, so it earns the baseline 3. It does reinforce the example symbol but does not explain edge cases like omitting the parameter.

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 function: it returns the canonical on-chain address for every token the system operates on, sourced from the registry that the rails themselves use. It distinguishes itself as the authoritative token-address reference, especially with the explicit warning about ECOWEALTH versus EWP, which sets it apart from sibling token 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 explicit timing guidance: 'Ask this BEFORE using any token address.' It clearly explains the critical context for safe use, though it does not explicitly list when-not-to-use or alternative sibling tools, which would be needed for a 5.

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