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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, but the description goes further by disclosing the capping rule for the priority fee and the returned breakdown (wei/gwei/ETH, burned and tip parts, upfront max reservation). That is real behavioral context an agent could not get from the annotation block.

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 formula and return-value sentence are well front-loaded and earn their place. The trailing sentences are generic scaffolding ('Follow its required fields and exact choices', 'Do not pass the REST calculator field inside MCP arguments') that add noise and are partly unintelligible in an MCP context.

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?

An output schema exists, so return values need not be exhaustively re-explained, and the description still summarizes the key outputs. Together with the formula, cap rule and nesting requirement, an agent has enough to call this correctly; only the interaction among the three fee parameters remains unaddressed.

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?

Top-level schema description coverage is 0% (inputs and modelVersion are undocumented), so the description must compensate. It does add structural meaning — all tool fields go inside a nested 'inputs' object, and units/modelVersion are conditional — but it does not explain how base_fee_gwei, priority_fee_gwei and max_fee_gwei relate or what the defaults mean, leaving that to the nested property 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?

States a specific computation and resource: 'Ethereum/EVM EIP-1559 fee' with the exact formula gas used x (base fee + priority fee), plus the max-fee cap rule. The Ethereum/EIP-1559 qualifier makes it distinguishable from the BTC and Solana fee siblings without opening any schema.

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 by the formula (compute an EVM fee when you have gas used and fee figures), but there is no explicit when-to-use or when-not guidance against buscalc_chain_btc_fee or buscalc_chain_solana_fee. The remaining sentences give invocation mechanics (nest under inputs, only pass listed fields), not selection guidance.

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