list_chain_tokens

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

Annotations already declare readOnlyHint=true. The description adds useful return-shape context ('symbol, address, decimals, and name') and specifies the static registry scope. It does not explain behavior for unsupported chains, but this is minor for a simple read-only list 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 tightly worded sentences. The first states the action and scope, the second lists the exact return fields. No filler or redundancy.

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 one-parameter read-only list tool with no output schema, the description is sufficient: it names the registry, the chain scoping, and the return fields. It doesn't discuss unsupported-chain errors, but that is acceptable given the low complexity and annotations.

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 description coverage is 100%—the only parameter, chainId, is fully documented as 'EVM chain ID'. The description adds no new parameter semantics beyond pointing to 'a specific chain', so the baseline of 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 uses a specific verb ('List') and resource ('all well-known tokens in the built-in registry for a specific chain'). This clearly distinguishes it from broader market/explorer token tools, which focus on prices, balances, or on-chain data.

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 provides clear context: use when you need the canonical well-known token list from the built-in registry for a specific EVM chain. It does not explicitly name alternatives or exclusions, but the 'built-in registry' scoping makes the intended use apparent.

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