list_supported_chains

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

The description adds the output fields (chain IDs, names, native currencies) beyond the readOnlyHint annotation, but it does not disclose details like response size, ordering, or whether the list is static or dynamic. The annotation already covers the safety profile, so this is adequate but not rich.

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, front-loaded sentence that clearly and efficiently communicates the tool's purpose and output. There is 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 zero-parameter, read-only listing tool, the description is largely complete: it names the resource and the key output fields. It could be slightly more explicit about the return type (e.g., an array of chain objects), but that is reasonably implied by 'List all...'.

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 input schema has no parameters, and the rubric sets a baseline of 4 for zero-parameter tools. The description appropriately focuses on the output contents, which is the only semantic information an agent needs.

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 the specific verb 'List' with a clear resource ('all supported EVM chains') and specifies the returned attributes: chain IDs, names, and native currencies. This distinguishes it from sibling tools like evm_get_chain_info, which provides details for a single chain.

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 no guidance on when to use this tool versus alternatives such as evm_get_supported_networks, lifi_get_chains, or list_chain_tokens. It states only what the tool does, not why or when it should be selected.

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