Content Engine

Content Engine

AI-powered content creation as a service. Generate scripts, images, and videos from any topic.

This is an MCP server accessible via Streamable HTTP transport. Any MCP-compatible client can connect to it directly — no proprietary CLI or binary required. Public tools (pricing, quotes) work without credentials. Brand-scoped reads require an API key. Paid tools use the x402 protocol for per-request USDC payments, or an API key with prepaid tokens.

Connection

Content Engine is a standard MCP server. Connect using any MCP client that supports Streamable HTTP transport.

MCP endpoint: https://content-engine-x402.fly.dev/mcp

Server discovery: https://content-engine-x402.fly.dev/.well-known/mcp.json

No special binary, CLI tool, or SDK is required. The server follows the MCP specification and works with any compliant client.

Required Environment Variables

Important: WALLET_PRIVATE_KEY gives the x402 client library the ability to sign USDC transfer authorizations. This key should be for a dedicated agent wallet with limited funds — not a primary wallet. See the Payment section for details on how funds are protected.

Payment — How It Works

Paid tools use the x402 payment protocol for USDC payments on the Base network (EIP-155 chain 8453).

The agent controls every payment

No funds are ever auto-debited. The payment flow is:

1. Agent calls a paid tool (e.g. create_script)
2. Server responds with HTTP 402 Payment Required containing the exact USDC amount, recipient wallet, and network
3. The agent's x402 client library reads the 402 response and presents the payment for authorization — the agent decides whether to sign
4. If the agent authorizes, the client signs a USDC transfer for the exact amount specified and retries the request with the signed payment proof
5. Server verifies the payment, settles the transaction on-chain, and processes the request

Each payment is explicit, per-request, and for an exact amount. The server cannot withdraw funds, charge more than the stated amount, or initiate payments. The agent (or its x402 client) must actively sign each transaction.

What the agent needs

To make paid calls, the agent's HTTP client must support x402. The recommended approach:

import { wrapFetch } from "@x402/fetch";
import { createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { base } from "viem/chains";

// Create wallet from the dedicated agent wallet key
const account = privateKeyToAccount(process.env.WALLET_PRIVATE_KEY);
const wallet = createWalletClient({ account, chain: base, transport: http() });

// Wrap fetch — paid requests are handled via 402 → sign → retry
const x402fetch = wrapFetch(fetch, wallet, "eip155:8453");

The wrapped fetch handles the 402 challenge-response cycle. Public tools (pricing, quotes) work with plain fetch — no wallet needed. Brand-scoped reads use an API key with plain fetch — also no wallet needed.

Cost control

• Call get_quote (public, no auth) before any paid tool to see the exact USDC price and per-stage breakdown
• Call get_pricing (public, no auth) to see all current rates
• Call get_queue_status (requires API key) to check daily budget remaining for your brand
• Use a dedicated wallet with limited USDC to cap total exposure
• Use sandbox mode to test without any payment (see below)

Typical Pricing

Pricing is dynamic — costs vary based on video duration, narration, and effects.

Always call get_quote with your parameters for the exact price.

Sandbox Mode (Free Testing)

Test the full API flow without payment, wallet, or USDC. Send Authorization: Bearer sandbox with any paid request to receive a mock response with the real cost quote attached.

# Get a quote (always free, no auth needed)
curl -X POST https://content-engine-x402.fly.dev/agent/quote \
  -H "Content-Type: application/json" \
  -d '{"operation":"script","duration_seconds":60}'

# Test a paid endpoint in sandbox mode (no payment, no wallet needed)
curl -X POST https://content-engine-x402.fly.dev/agent/script \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sandbox" \
  -d '{"topic":"How AI is changing music production"}'

Sandbox mode returns:

• The exact USDC price you would pay
• A per-stage cost breakdown showing which AI services are used
• The response structure your agent should expect from real calls
• Mock IDs (content_id, jobId, transactionId) matching the real format

Sandbox mode does not create content, charge USDC, require a wallet, or count toward rate limits.

Available Tools

Public (no auth — call anonymously)

Brand-scoped reads (no USDC charge, but require API key)

These tools return data tied to a specific brand, so the server needs to know which brand is asking. Pass Authorization: Bearer ce_... on the MCP connection. Called without an API key, they return a structured auth_required message pointing at the dashboard.

Paid (x402 USDC per call, OR API key with prepaid tokens)

Two ways to pay

• x402 USDC (per-call) — No account needed. The x402 client library handles HTTP 402 → sign USDC transfer → retry. See the Payment section above. Called with no auth, paid tools return a payment_required response with the exact price and the x402 REST endpoint.
• API key + prepaid tokens — Buy tokens via purchase_tokens, credited to a brand. Use the brand's API key (Authorization: Bearer ce_...) on the MCP connection to spend tokens on paid calls without per-call wallet signing.

Typical Workflow

Quick path

get_quote(operation="full_pipeline") → run_full_pipeline → poll get_content_status → get_content

Step-by-step path

1. get_quote operation="script" — See exact price
2. create_script topic="..." — Generate script, save returned content_id
3. get_content_status content_id="..." — Poll until complete
4. get_quote operation="video" — See exact price for video
5. create_video content_id="..." — Generate video
6. get_content_status content_id="..." — Poll until ready (1–5 min)
7. get_content content_id="..." — Retrieve video URL and metadata

Important Notes

• Video generation takes 1–5 minutes. Always poll get_content_status rather than assuming instant completion. Polling requires an API key (it's brand-scoped).
• The content_id (UUID) returned by creation tools is the key for all subsequent operations.
• Pricing is dynamic — always call get_quote before paid operations to see the exact cost.
• Use sandbox mode (Authorization: Bearer sandbox) against the x402 REST endpoints to test without spending USDC.
• Use a dedicated agent wallet with limited funds — do not use a primary wallet.