occ-cloudflare

Cryptographic proof signing for Cloudflare Workers. Every tool/binding call gets an Ed25519-signed proof pair returned alongside the result.

Unlike other OCC integrations, proofs are returned (not written to disk) since Cloudflare Workers have no filesystem. Store them wherever you like (KV, D1, R2, Durable Objects).

Install

npm install occ-cloudflare

Usage

Wrap a tool

import { occWrapTool } from "occ-cloudflare";

const searchTool = {
  execute: async (args: { query: string }) => {
    return await doSearch(args.query);
  },
};

const wrapped = occWrapTool(searchTool, "search");
const { result, proofs } = await wrapped.execute({ query: "OCC" });

// Store proofs in KV, D1, R2, etc.
await env.PROOF_LOG.put(`proof-${Date.now()}`, JSON.stringify(proofs));

Wrap a binding

import { occWrapBinding } from "occ-cloudflare";

export default {
  async fetch(request: Request, env: Env) {
    const kv = occWrapBinding(env.MY_KV, "my-kv");

    const { result, proofs } = await kv.get("some-key");
    // result = the KV value
    // proofs = pre/post Ed25519-signed proof entries
  },
};

Configuration

interface OCCCloudflareOptions {
  measurement?: string;  // Default: "occ-cloudflare:stub"
  agentId?: string;      // Default: "cloudflare-worker"
}

How it works

1. occWrapTool() wraps a tool's execute with pre/post proof signing
2. occWrapBinding() wraps all methods on a Cloudflare binding via Proxy
3. An ephemeral Ed25519 key pair is generated in-memory per Worker invocation
4. Pre-execution proof: Ed25519 signature over SHA-256 of tool name + arguments
5. Post-execution proof: signature over tool name + args + result
6. Proofs are chained via prevB64 for tamper-evident ordering
7. No filesystem access — proofs are returned, not written to disk

Verify

Collect proof entries and write them to a .jsonl file, then:

npx occ-mcp-proxy verify proof.jsonl