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

Annotations already declare read-only, idempotent, open-world, non-destructive, so the safety profile is covered. The description adds real operational context beyond that: a single API key covers all chains, and archive access is requestable via ?archive=1. It does not say whether the list is paginated or how 'live status' is determined.

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?

One densely packed sentence, front-loaded with the verb and scope, and the parenthetical about the shared API key is placed where it matters. No filler.

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?

With no output schema, the description usefully enumerates the return fields, which is exactly what an agent needs for a discovery endpoint. Minor gaps remain around pagination and the optional filters, but nothing critical for correct invocation of a zero-required-param list tool.

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 coverage is 100% with both parameters fully described in the schema, so the baseline is 3. The description mentions neither the query filter nor evm_only; its ?archive=1 note describes a chain attribute rather than an input parameter, so it adds no parameter guidance.

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?

Specific verb ('List') plus resource ('every blockchain SwiftNodes serves'), with the scope word 'every' implicitly contrasting with the singular sibling get_chain. It also enumerates the returned attributes (name, slug, chain ID, live status, WebSocket/archive availability), so an agent knows exactly what it gets.

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?

Usage is implied by the enumeration scope — reach for this to discover chains, then get_chain for one. But there is no explicit when/when-not guidance or named alternative, so the agent must infer the routing against get_chain and probe_endpoint.

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