encode_unsigned_transaction

THE RISK

High Risk

Why encode_unsigned_transaction needs a policy

This tool serializes/encodes transaction objects into a format ready for signing and submission to the Algorand blockchain. While encoding itself doesn't submit or execute a transaction, it is a critical step in the transaction pipeline that prepares blockchain operations. It's more than a pure read (it transforms data), and the output directly enables financial/destructive on-chain actions.

From the tool's definition Encode a transaction object into base64 unsigned transaction bytes (msgpack). Accepts output from make_*_txn or assign_group_id.

Documented attack patterns abuse exactly the kind of access encode_unsigned_transaction gives an agent:

POLICY

How to control encode_unsigned_transaction

PolicyLayer is an MCP gateway — it sits between your AI agents and Algorand MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for encode_unsigned_transaction:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "encode_unsigned_transaction": {
      "limits": [
        {
          "counter": "encode_unsigned_transaction_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

encode_unsigned_transaction stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Algorand MCP — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Algorand MCP tools

Financial alpha_amend_order Edit an existing unfilled Alpha Arcade order in-place (change price, quantity, or slippage Financial alpha_cancel_order Cancel an open Alpha Arcade order. Requires escrowAppId and orderOwner. Refunds USDC/token Financial api_ultrade_market_cancel_orders Cancel multiple open orders Financial api_haystack_execute_swap Execute an optimized token swap via Haystack Router — gets the best route across multiple Financial api_ultrade_wallet_withdraw Withdraw token Financial api_ultrade_wallet_withdraw_message Generate message from the withdrawal data Financial make_asset_transfer_txn Create an asset transfer transaction Financial alpha_claim Claim USDC from a resolved Alpha Arcade market by redeeming outcome tokens. Winning = 1:1

All 172 Algorand MCP tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

Govern code and CI agents → Branch allowlists, approval on merges, and rate caps on the build and pipeline tools agents trigger.
High-risk tools in Algorand MCP → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about encode_unsigned_transaction

What does the encode_unsigned_transaction tool do? +

Encode a transaction object into base64 unsigned transaction bytes (msgpack). Accepts output from make_*_txn or assign_group_id. It is categorised as a Execute tool in the Algorand MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on encode_unsigned_transaction? +

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

What risk level is encode_unsigned_transaction? +

encode_unsigned_transaction is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit encode_unsigned_transaction? +

Yes. Add a rate_limit block to the encode_unsigned_transaction 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 encode_unsigned_transaction completely? +

Set action: deny in the PolicyLayer policy for encode_unsigned_transaction. 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 encode_unsigned_transaction? +

encode_unsigned_transaction is provided by the Algorand MCP server (goplausible/algorand-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Algorand MCP tool call.

Start from Algorand MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →