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

With no annotations, the description carries the full burden. It discloses that data is read live from public RPCs, and openly explains the two-step paid x_payment process (call without it for terms, then with it to settle). It stops short of stating read-only guarantees or rate limits, but the payment requirement and data source are well covered.

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 four sentences, front-loaded with the core function, then conditional usage, payment protocol, and alternative. Every sentence adds necessary information with no fluff or redundancy.

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?

Given the complexity (optional tx_type, paid flow, multi-chain support, no output schema), the description covers the main functional modes and the payment sequence. It hints at return values ('tx-ready wei', 'USD cost') but doesn't fully specify the response shape. The alternative pricing tool is mentioned, providing a complete usage picture.

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%, so baseline is 3. The description adds meaningful semantics beyond the schema by explaining that tx_type returns USD cost including the OP-stack L1 data fee, and by detailing the x_payment flow. This goes beyond the schema's simple field descriptions.

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 the tool returns bid-ready EIP-1559 fees for a selected chain, with an optional tx_type mode for USD transaction costs. It distinguishes itself from the 'pricing' sibling by noting that 'pricing' lists every price at once, while this tool focuses on one chain.

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 provides explicit guidance on when to use tx_type (for USD cost of a specific transaction), and points to an alternative: 'The free `pricing` tool lists every price at once.' It also details the paid flow with x_payment, giving clear usage instructions.

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