Paid ($0.02). Get the current Ethereum mainnet gas price. Returns base fee, priority fee, and max fee in wei and gwei. Useful for estimating transaction costs.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "chain_gas_price"
}
}| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, this description carries the full burden and does disclose material behavior: it is a paid call ($0.02) and it is mainnet-only. It also states the return composition (base fee, priority fee, max fee in both wei and gwei), which compensates for the absent output schema. It stops short of saying whether the price is live/spot or cached, and no rate-limit or failure behavior is described.
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?
Three short sentences, front-loaded with the cost signal so an agent sees the paid nature before anything else. Every clause carries information; nothing is redundant with the schema.
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, single-purpose read tool with no output schema, the description covers cost, chain scope, and the exact return fields. Nothing an agent needs in order to decide to call it, or to interpret the result, is missing.
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 tool takes zero parameters, so the schema baseline of 4 applies and there is nothing further for the description to disambiguate. It correctly adds no parameter discussion, which is the right call.
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?
Specific verb plus resource ('Get the current Ethereum mainnet gas price') scoped to a single chain, which cleanly separates it from the chain_balance / chain_block_number / chain_tx read siblings. An agent can tell what it returns without opening anything else.
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 closing clause 'Useful for estimating transaction costs' implies the usage context, but there is no explicit when-to-use versus when-not, and no named alternative among the sibling read tools (e.g. when to fetch gas versus a full fee estimate). Implied usage only.
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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