Current gas on one EVM chain: base fee and slow/standard/fast priority fee in gwei, and USD cost of a native transfer, an ERC-20 transfer and a Uniswap swap including the L1 data fee on rollups. Price: $0.001 USDC per call, paid with x402 on Base.
| Name | Required | Description | Default |
|---|---|---|---|
| chain | Yes | ethereum, base, arbitrum, optimism, polygon or bsc |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, but the description carries real behavioral weight: it discloses the payment model ($0.001 USDC per call via x402 on Base), which an agent must know before invoking, and it clarifies that rollup quotes fold in the L1 data fee. It does not discuss failure modes for unsupported chains or data freshness, but core operational context is present.
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?
Two sentences, zero filler: the first front-loads output contents, the second front-loads pricing. Every clause (gwei units, rollup L1 fee inclusion, payment rail) supplies information an agent needs before calling.
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 single-parameter read tool with no output schema and no annotations, the description covers what is returned and what it costs, which is the critical missing structure. Minor gaps remain around unsupported-chain behavior and whether values are a live snapshot or cached, but nothing essential to a correct call is absent.
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% and the chain parameter's schema description already lists the six accepted values (ethereum, base, arbitrum, optimism, polygon, bsc). The description adds only the framing of 'one EVM chain' and does not enrich the parameter beyond the schema, so the baseline 3 applies.
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 resource ('current gas on one EVM chain') and enumerates exactly what is returned: base fee, slow/standard/fast priority fees in gwei, and USD costs for native, ERC-20 and Uniswap swap transactions including rollup L1 data fees. This clearly separates it from the sibling gas_compare (multi-chain comparison) without needing to open the 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?
The phrase 'on one EVM chain' implies this is the single-chain variant and that gas_compare handles the multi-chain case, but the description never names gas_compare or states an explicit when-to-use rule. The agent must infer the routing decision from the 'one EVM chain' scope alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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