list_chains

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

With no annotations provided, the description carries the behavioral disclosure burden. It reveals the operation is a read-only list, the scale (75+ chains), the auth context ("one API key for all"), and the returned fields. It does not mention pagination, sorting, or rate limits, but for a straightforward list tool this is adequate.

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?

Three short sentences, each earning its place: the first states the primary action and scope, the second lists return fields, and the third gives usage guidance. The most important information is front-loaded with no filler or repetition.

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 two-optional-parameter list tool with no output schema, the description covers the core essentials: what it lists, what fields it returns, and when to use it. The only minor gap is the lack of edge-case behavior (e.g., empty results or unfiltered payload size), but the 75+ chains note already sets expectations.

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%: both query and evm_only are already clearly described with examples in the input schema. The tool description adds no extra parameter-level detail, so the baseline score of 3 applies.

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 states a specific verb and resource: "List every blockchain SwiftNodes serves." It further distinguishes itself from siblings by naming the return payload (name, slug, chain ID, category, docs page) and pointing to get_chain as a complementary tool, making its unique role unmistakable.

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 final sentence gives explicit usage guidance: "Use before get_chain if unsure of the exact chain name." This names an alternative tool and the precise condition that selects list_chains, implying the inverse condition (when you know the chain name, use get_chain). That is actionable and leaves little to inference.

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