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

With no annotations, the description must carry the behavioral burden. It does add useful context: the faucet route is free, requires only a signature, and needs no gas, and bridges are 'measured live.' Yet it does not explicitly state that this is a read-only informational guide or what the tool returns, leaving some ambiguity about whether it performs actions like claiming.

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?

The description is a single compact sentence that front-loads the core purpose and then enumerates the covered routes in a clear list. The repetition of 'Free' at the end is slightly redundant but not harmful, and the overall length is appropriate for a 0-parameter tool.

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 parameterless informational tool without an output schema, the description provides enough detail about the guide's contents to let an agent decide whether to invoke it. It names all major routes and even hints at cost nuances, so the agent can route the user appropriately even if exact output formatting is not specified.

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 input schema is empty with zero parameters, so the baseline is 4. There are no parameters for the description to explain, and the tool appears intentionally parameterless as a general informational guide.

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 identifies the tool's purpose: providing routes for getting USDC onto Arc. It lists specific methods (faucet, bridges, CCTP, Gateway, Onramp Kit), which distinguishes it from narrower sibling tools like arc_bridges or arc_faucet_claim, though it never uses a direct verb like 'shows' or 'explains.'

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 phrase 'every route we know works' implies this is the comprehensive guide for onboarding USDC to Arc, giving agents context on when to prefer it. However, it does not explicitly say when to use this tool instead of more specific siblings like arc_bridges or arc_cctp_cost, nor when not to use it.

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