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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is fully covered. The description adds content-level context (billing model, what is excluded) but says nothing about the shape, granularity, or currency of what comes back.

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 short clauses, front-loaded with the resource, then the qualifier that prevents misreading. Nothing is padded, though the fragment style leaves the action verb implicit.

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 no-arg, read-only lookup with no output schema, the description covers the essentials by naming the pricing fields returned and clarifying that usage-based billing is out of scope. It stops short of describing the response structure (single plan vs. list, currency, units) that an agent might want without an output schema.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a no-param tool is 4. The description correctly does not invent parameter semantics.

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 names the resource (SwiftNodes plans) and enumerates the pricing dimensions it covers (flat monthly price, HTTP and WebSocket rate limits), which is enough to tell it apart from siblings like get_account, get_chain, or rpc_call. It never uses an explicit verb such as 'returns', so the retrieval intent is inferred rather than stated.

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: call this when you need SwiftNodes plan pricing. The negative clauses ('no compute units, no per-request billing') usefully head off a wrong expectation, but there is no explicit when-to-use statement or reference to an alternative tool for other billing questions.

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