External wallet signing path — use this instead of passing signing payloads directly to haiku_execute when WALLET_PRIVATE_KEY is not set or when a wallet MCP (Coinbase Payments MCP, wallet-agent, etc.) handles signing. Extracts and normalizes the EIP-712 payloads from a quote into a standard form...
Part of the Haiku DeFi MCP MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use haiku_prepare_signatures to create or modify resources in Haiku DeFi MCP. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call haiku_prepare_signatures repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Haiku DeFi MCP.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
tools:
haiku_prepare_signatures:
rules:
- action: allow
rate_limit:
max: 30
window: 60See the full Haiku DeFi MCP policy for all 7 tools.
Agents calling write-class tools like haiku_prepare_signatures have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.
External wallet signing path — use this instead of passing signing payloads directly to haiku_execute when WALLET_PRIVATE_KEY is not set or when a wallet MCP (Coinbase Payments MCP, wallet-agent, etc.) handles signing. Extracts and normalizes the EIP-712 payloads from a quote into a standard format any wallet's signTypedData can consume. Pass quoteId (preferred) — the server resolves the full quote from session cache. Alternatively pass the full quoteResponse object if quoteId is unavailable. After signing externally, pass permit2Signature and/or userSignature to haiku_execute.. It is categorised as a Write tool in the Haiku DeFi MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Add a rule in your Intercept YAML policy under the tools section for haiku_prepare_signatures. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Haiku DeFi MCP MCP server.
haiku_prepare_signatures is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the haiku_prepare_signatures rule in your Intercept 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 Intercept policy for haiku_prepare_signatures. 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.
haiku_prepare_signatures is provided by the Haiku DeFi MCP MCP server (haiku-mcp-server). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.