List chains indexed by Avalanche Data API

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds useful context about the data source (Glacier API) and return fields, but does not disclose behavioral details like pagination, result limits, or what happens when the network filter is omitted. With annotations carrying the safety profile, a 3 is appropriate.

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 front-loaded sentences with zero filler. The main action and resource lead, followed by data fields and the usage note. Slightly more relational than strictly necessary, but each part earns its place and it is easy for an agent to parse quickly.

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?

Complete for a simple discovery tool: one optional parameter fully documented in schema, strong annotations covering safety, and a description that states scope, return fields, and the primary use case. Minor gaps remain — no mention of result ordering, pagination, or default behavior when network is absent — but for a list tool these are low-impact.

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 single optional 'network' parameter is already documented ('Filter by environment' with mainnet/testnet enums). The description does not add parameter-specific guidance, so the schema does the heavy lifting, warranting the baseline 3.

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?

States a specific verb+resource ('List every chain (C-Chain + L1s) indexed by the Avalanche Data API') and enumerates the exact data returned (chain ID, name, RPC, explorer, native token, testnet flag). It also distinguishes itself from the built-in registry, helping an agent tell it apart from siblings like avax_list_networks.

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?

'Best way to discover L1s beyond the built-in registry' frames when to prefer this tool and implies the built-in registry is covered elsewhere (i.e., avax_list_networks). It gives clear context for the L1-discovery use case, though it does not explicitly name the sibling to use when the built-in registry is needed.

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