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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description adds valuable context beyond that: the call is free and keyless, the route list is intentionally closed, and the governing rules include gas pricing, a per-transaction fee cap, and EARTH's one-way token physics. This gives the agent useful expectations about cost, authentication, and domain constraints.

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 defines scope and content, the second clarifies intentional absence, and the third states access cost, authentication, and safety. The most important scoping information is front-loaded.

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 read-only, zero-parameter reference tool with an output schema, this description is complete. It names the exact content area, the laws covered, the closed-set behavior, and the lack of authentication requirements. An agent can decide whether to call this tool and what to expect from it without further ambiguity.

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 has zero parameters and the schema covers 100% of them, so the description carries no parameter-documentation burden. It appropriately focuses on what the resource contains rather than repeating empty schema fields.

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 clearly states that the tool exposes the authoritative, restricted set of asset conversions the system may perform, along with the rules governing them. It goes beyond the title by emphasizing that unlisted edges are intentionally absent, which gives the tool a well-defined scope. It does not explicitly name a sibling tool to differentiate from, but the phrase 'the only asset conversions our rails may perform' is specific enough.

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 implies that this tool should be used to determine which conversion routes are permitted and that anything not listed is intentionally unsupported. However, it never explicitly states when to prefer this tool over alternatives like crypto_lanes, prepare_bridge, or payment_options. The usage context is inferable but not directly stated.

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