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

Reads/computes only and changes nothing aligns with the annotations, and it discloses the revert behavior (422 with reason, uncharged) plus charging and free-call terms, which is useful. However, the statement that each call is charged and repeats are not free slightly conflicts with the idempotentHint=false annotation rather than clarifying it, creating some ambiguity for an agent deciding whether to retry.

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?

Front-loaded with the core purpose and scope, then usage, example, and pricing. Efficient, though the pricing and payment details (x402 USDC, card key, first 25 free) add length that is only tangentially about the tool's function.

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?

Although there is no output schema, the description states the return shape (gas units, gwei, S) and the error behavior (422 on revert), which is enough for an agent to call and interpret results.

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%, so the schema already documents all four parameters. The description adds some meaning (value in S, calldata for a contract call, sender only when the call depends on it) but stays at a level the schema largely conveys.

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?

Names the specific verb and resource (estimate gas for a transaction on Sonic), gives the underlying RPC method, and states exactly what is returned (gas units, gwei, S). It is clearly distinguished from sonic_gas and sonic_call.

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?

Explicitly says when to use it (before sending a transaction, to price a batch) and names the alternative for the adjacent need ('for the gas price alone use sonic_gas'). The revert case is also called out.

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