verify_tx_decode

SERVERVaultPilot MCP SOURCEvaultpilot-mcp

Low RISK CLASS

Category Read

Parameters 11 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-szhygulin-vaultpilot-mcp/verify-tx-decode.md

WHAT IT DOES

What verify_tx_decode does on VaultPilot MCP

AI agents call verify_tx_decode to retrieve information from VaultPilot MCP 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
`handle`	string	Yes	Opaque handle returned by any prepare_* tool. Use this when the original prepare_* response (and its VERIFY-BEFORE-SIGNING block) has been dropped from your con

Parameters from the server's own tool schema.

RISK

Why verify_tx_decode is rated Low

verify_tx_decode is purely a validation and inspection tool. It decodes and compares transaction calldata against a public registry (4byte.directory) to verify correctness before execution. While it operates on sensitive financial data (crypto transactions), it performs no side effects—no funds move, no state changes, no code execution.

From the tool's definition Tool performs "Independent server-side cross-check" and "Fetches the function signature(s)" and "re-decodes the calldata" — all read-only verification operations. Returns a VerifyDecodeResult with status values like 'match', 'mismatch', 'no-signature'.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs verify_tx_decode safely

PolicyLayer is an MCP gateway: it sits between your AI agents and VaultPilot MCP, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For verify_tx_decode, this is the rule to start with:

verify_tx_decode Allowed

verify_tx_decode is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "verify_tx_decode": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect VaultPilot MCP, apply this rule, and every verify_tx_decode call is checked against it from then on.

FAQ

Questions about verify_tx_decode

What does the verify_tx_decode tool do? +

Independent server-side cross-check of a prepared EVM tx's calldata. Fetches the function signature(s) registered for the 4-byte selector on 4byte.directory (a public registry), re-decodes the calldata via viem against each candidate, and re-encodes to prove the signature describes the exact calldata bytes losslessly. Returns a VerifyDecodeResult whose summary field is pre-written for end-user consumption — the orchestrator should relay it verbatim. Status values: match (independent decode agrees with local ABI), mismatch (function-name disagreement — DO NOT SEND), no-signature / error / not-applicable (no independent check possible; fall back to the swiss-knife URL). On TRON, returns not-applicable — TRON transactions carry no 4-byte selector so this cross-check doesn't apply. Handle is the same opaque ID returned by any prepare_* tool. NEVER do this check by scripting ad-hoc WebFetches to 4byte or swiss-knife; always call this tool so the check runs through a single auditable code path. This is deliberately more expensive than a 4byte-selector lookup — it proves the FULL calldata (not just the function name) is consistent with the independent signature. It is categorised as a Read tool in the VaultPilot MCP MCP Server, which means it retrieves data without modifying state.

What parameters does verify_tx_decode accept? +

verify_tx_decode accepts 1 parameter: handle. Required: handle. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on verify_tx_decode? +

Register the VaultPilot MCP server in PolicyLayer and add a rule for verify_tx_decode: 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 VaultPilot MCP. Nothing to install.

What risk level is verify_tx_decode? +

verify_tx_decode is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit verify_tx_decode? +

Yes. Add a rate_limit block to the verify_tx_decode 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.

How do I block verify_tx_decode completely? +

Set action: deny in the PolicyLayer policy for verify_tx_decode. 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.

What MCP server provides verify_tx_decode? +

verify_tx_decode is provided by the VaultPilot MCP server (vaultpilot-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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