eth_call
chainpeek: Call a smart contract function read-only on Ethereum, Base or Robinhood Chain. For gas units use estimate_gas; for a raw storage slot use get_storage_at. Returns the raw ABI-encoded return data (result, result_bytes) of eth_call against to with your calldata at latest, pending, finaliz...
This record as markdown: /tools/dev-tanod-tanod/eth-call.md
What eth_call does on Tanod
AI agents call eth_call to retrieve information from Tanod without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
to | string | Yes | Contract (or account) to call. |
data | string | Yes | ABI-encoded calldata, 0x-hex with an even number of digits, at most 8 kB (4-byte selector + arguments; 0x18160ddd is totalSupply()). |
block | object | — | latest (default), pending, finalized or a block number (older blocks need an archive node and may fail). |
chain | string | Yes | ethereum, base or robinhood (Robinhood Chain, chain id 4663). |
Parameters from the server's own tool schema.
Why eth_call is rated Low
Even though eth_call only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs eth_call safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Tanod, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For eth_call, this is the rule to start with:
eth_call is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Tanod, apply this rule, and every eth_call call is checked against it from then on.
Questions about eth_call
chainpeek: Call a smart contract function read-only on Ethereum, Base or Robinhood Chain. For gas units use estimate_gas; for a raw storage slot use get_storage_at. Returns the raw ABI-encoded return data (result, result_bytes) of eth_call against to with your calldata at latest, pending, finalized or a block number; nothing is signed or sent. The result is not decoded (decode_calldata decodes calldata; the ABI is yours). A call that reverts is a 422 reverted (not charged); results over 32 kB are a 502. Old blocks need an archive node and may fail. Ethereum, Base and Robinhood only; read-only: nothing is signed or sent. RPC reads are cached up to 30 s. A bad address, hash, hex string, block or range is a 422 before any payment (not charged). Typically under 1 s. Price: USD 0.002. Free: 10 chain reads per IP per UTC day. Docs: https://tanod.dev/learn/ethereum-rpc-reads-api.html. It is categorised as a Read tool in the Tanod MCP Server, which means it retrieves data without modifying state.
eth_call accepts 4 parameters: to, data, block, chain. Required: to, data, chain. The full parameter table on this page comes from the server's own tool schema.
Register the Tanod MCP server in PolicyLayer and add a rule for eth_call: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Tanod. Nothing to install.
eth_call is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the eth_call rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for eth_call. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
eth_call is provided by the Tanod MCP server (https://tanod.dev/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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