Critical Risk →

hydra_send_btc

Send BTC from a Chain-Signature-derived Bitcoin address. UTXO selection via Mempool API. SAFE: dry=true returns the plan; dry=false signs via MPC and broadcasts. Amount in satoshis (1 BTC = 100,000,000 satoshi). Requires the derived address to have spendable UTXOs.

How to control hydra_send_btc ↓

What hydra_send_btc does on Near Hydra

AI agents use hydra_send_btc to commit financial operations through Near Hydra — usually the final step of a payment, billing, or trading workflow. A call moves real money.

Critical Risk

Why hydra_send_btc needs a policy

This tool sends Bitcoin (a financial asset) on-chain. When dry=false, it signs and broadcasts a real transaction, irreversibly moving funds. This is a financial operation with critical blast radius if misused by an AI agent, as it can drain BTC holdings.

From the tool's definition Send BTC from a Chain-Signature-derived Bitcoin address... dry=false signs via MPC and broadcasts. Amount in satoshis

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

How to control hydra_send_btc

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

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "hydra_send_btc": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

Any call to hydra_send_btc is blocked until a human approves it. The rest of the server keeps working.

  1. Create a free account and register Near Hydra — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
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Related tools and policies

Go deeper

Questions about hydra_send_btc

What does the hydra_send_btc tool do? +

Send BTC from a Chain-Signature-derived Bitcoin address. UTXO selection via Mempool API. SAFE: dry=true returns the plan; dry=false signs via MPC and broadcasts. Amount in satoshis (1 BTC = 100,000,000 satoshi). Requires the derived address to have spendable UTXOs. It is categorised as a Financial tool in the Near Hydra MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on hydra_send_btc? +

Register the Near Hydra MCP server in PolicyLayer and add a rule for hydra_send_btc: 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 Near Hydra. Nothing to install.

What risk level is hydra_send_btc? +

hydra_send_btc is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit hydra_send_btc? +

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

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

hydra_send_btc is provided by the Near Hydra MCP server (nikshepsvn/near-hydra). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Near Hydra tool call.

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

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21 Near Hydra tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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