FreeTier Agent API

base-gas

base_gas

Read-only

3 free MCP calls per day (all tools together), then $0.0015 USDC via x402 or card credits (paid in-band: params._meta["x402/payment"]). Base gas price: Live Base mainnet gas price (gwei), latest block, and estimated ETH cost of a USDC transfer (~65k gas) and a plain ETH transfer (21k gas). When to use: Use base-gas for current Base gas price and the cost of a transfer.

Input Schema

Name	Required	Description	Default
No arguments

Output Schema

Name	Required	Description	Default
`at`	No
`rpc`	No
`note`	No
`block`	No
`network`	No
`sources`	No
`gas_price_wei`	No
`gas_price_gwei`	No
`eth_transfer_eth`	No
`usdc_transfer_eth`	No
`usdc_transfer_gas_estimate`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 26, 2026

changedOutput schema / description

Previous value: -"Inferred from a real response captured on 2026-10-24; extra fields may appear, null-valued fields are untyped."New value: +"Inferred from a real response captured on 2026-10-26; extra fields may appear, null-valued fields are untyped."

Changed1 schema field changedOct 24, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "description": "Inferred from a real response captured on 2026-10-24; extra fields may appear, null-valued fields are untyped.",
+  "properties": {
+    "at": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "block": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "eth_transfer_eth": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "gas_price_gwei": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "gas_price_wei": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "network": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "note": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "rpc": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "sources": {
+      "items": {
+        "properties": {
+          "name": {
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "url": {
+            "type": [
+              "string",
+              "null"
+            ]
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "usdc_transfer_eth": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "usdc_transfer_gas_estimate": {
+      "type": [
+        "number",
+        "null"
+      ]
+    }
+  },
+  "type": "object"
+}

First observedOct 18, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds meaningful non-obvious behavior: the free-tier limit (3 calls/day), paid access via x402 or card credits, and the in-band payment mechanism (params._meta['x402/payment']). This is useful context beyond structured fields, though it does not describe latency or freshness guarantees.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact (three sentences) and contains no fluff. It front-loads pricing/payment behavior before the core purpose, which is slightly unconventional but still readable and purposeful; every sentence contributes.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only, zero-parameter tool with an output schema, the description covers purpose, usage, data returned, and payment behavior. It is complete enough to call correctly, with only minor gaps around chain comparison and freshness.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With zero parameters, the baseline is 4. The description does not need to explain inputs, and it correctly implies no user-supplied arguments are required for the core operation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific resource and scope: 'Live Base mainnet gas price (gwei), latest block, and estimated ETH cost of a USDC transfer (~65k gas) and a plain ETH transfer (21k gas).' This is clear and concrete, though it does not explicitly distinguish itself from the sibling tool 'gas' (which likely covers a broader or different chain scope).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It includes an explicit 'When to use' clause: 'Use base-gas for current Base gas price and the cost of a transfer.' However, it does not name alternatives (e.g., the sibling 'gas' tool) or state when not to use it, leaving the agent to infer routing between gas-related siblings.

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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