Create MCP Servers with MCPHero

MCPHero lets agents build their own tools. Instead of burning tokens on API schemas, SQL queries, and output parsing every run, the agent creates a persistent MCP server once and calls it forever. A 50,000-token integration becomes a 50-token tool call.

This skill covers the mcpheroctl CLI workflow for building servers end-to-end.

Production API base URL: https://api.mcphero.app/api

Prerequisites

Before using this skill, the user must have mcpheroctl installed and authenticated.

Install mcpheroctl

# via Homebrew (macOS/Linux)
brew install arterialist/mcpheroctl/mcpheroctl

# via uv (cross-platform)
uv tool install mcpheroctl

Authenticate

1. Log in to the MCPHero Dashboard.
2. Go to Settings → Organization → Developers.
3. Click Create API key and copy the token.
4. Run:

mcpheroctl auth login --token <YOUR_ORG_TOKEN>

Verify

mcpheroctl auth status

The Wizard Pipeline

The CLI follows this linear flow. After any async step, poll wizard state and check processing_status == "idle" before proceeding.

1. create-session          → Returns server_id (save it, needed everywhere)
2. conversation (loop)     → Gather requirements; stop when is_ready: true
3. start                   → Transition to tool suggestion (async → poll)
4. list-tools              → Review AI-suggested tools
5. refine-tools (optional) → Iterate on tools until satisfied (async → poll)
6. submit-tools            → Confirm selection (deletes unselected tools)
7. (auto env var suggest)  → Triggered automatically after submit-tools (async → poll)
8. list-env-vars           → Review suggested env vars
9. refine-env-vars (opt.)  → Iterate on env vars (async → poll)
10. submit-env-vars        → Provide actual values (call even if list is empty — backend needs it to transition)
11. set-auth               → Generate bearer token for the server
12. generate-code          → Trigger code generation (async → poll)
13. deploy                 → Deploy to MCPHero runtime → returns server_url + bearer_token

Always call submit-env-vars, even when list-env-vars returns []. The backend requires this step to transition to the next state. With no env vars, just call it with no --var flags.

State Machine

The setup_status field in wizard state tells you where you are:

gathering_requirements     → User is chatting about requirements
tools_generating           → LLM is generating tool suggestions (async, poll)
tools_selection            → Tools ready for review/selection
env_vars_generating        → LLM is generating env var suggestions (async, poll)
env_vars_setup             → Env vars ready for review/submission
auth_selection             → Ready for auth setup
code_generating            → LLM is generating code (async, poll)
code_gen                   → Code ready for review
deployment_selection       → Ready to deploy
ready                      → Server deployed and live

States ending in _generating are transient — poll until they transition. The processing_status field is the reliable check: "idle" means done, "processing" means wait, "error" means check processing_error.

Full Wizard Example

Always use --json for scriptable output. Without it, human-friendly messages go to stderr and can confuse parsing.

# 1. Create session
mcpheroctl wizard create-session --json
# → {"server_id": "abc-123-..."}
SERVER_ID="abc-123-..."

# 2. Describe requirements (iterate until is_ready: true)
mcpheroctl wizard conversation $SERVER_ID --json \
  -m "I have a PostgreSQL database with customers and orders tables. I need tools to find customers by name, fetch orders for a customer, and get last hour's orders."
# Repeat with follow-up messages until output shows: "is_ready": true

# 3. Start tool suggestion (async)
mcpheroctl wizard start $SERVER_ID --json
# → {"status": "processing"}

# Poll until processing is done (check processing_status, not setup_status)
until mcpheroctl wizard state $SERVER_ID --json 2>/dev/null | \
  python3 -c "import sys,json; exit(0 if json.load(sys.stdin).get('processing_status')=='idle' else 1)"; do
  sleep 3
done

# 4. Review tools (state should be "tools_selection")
mcpheroctl wizard list-tools $SERVER_ID --json

# 5. Refine if needed (async → poll again)
mcpheroctl wizard refine-tools $SERVER_ID --json \
  -f "Add error handling for missing customers. Rename get_customers_orders to get_orders_by_customer."

# 6. Submit selected tool IDs
mcpheroctl wizard submit-tools $SERVER_ID --json \
  --tool-id <tool-uuid-1> \
  --tool-id <tool-uuid-2> \
  --tool-id <tool-uuid-3>

# 7. Wait for env var suggestion (auto-triggered, state becomes "env_vars_setup")
until mcpheroctl wizard state $SERVER_ID --json 2>/dev/null | \
  python3 -c "import sys,json; exit(0 if json.load(sys.stdin).get('processing_status')=='idle' else 1)"; do
  sleep 3
done

# 8. Review env vars
mcpheroctl wizard list-env-vars $SERVER_ID --json

# 9. Submit env var values (format: VAR_UUID=VALUE)
# ALWAYS call this even if list-env-vars returned [] — backend needs it to transition.
# With env vars:
mcpheroctl wizard submit-env-vars $SERVER_ID --json \
  --var "<env-var-uuid-1>=localhost" \
  --var "<env-var-uuid-2>=5432"
# Without env vars (empty list):
mcpheroctl wizard submit-env-vars $SERVER_ID --json

# 10. Set authentication
mcpheroctl wizard set-auth $SERVER_ID --json
# → {"bearer_token": "..."}  ← SAVE THIS

# 11. Generate code (async → poll)
mcpheroctl wizard generate-code $SERVER_ID --json
until mcpheroctl wizard state $SERVER_ID --json 2>/dev/null | \
  python3 -c "import sys,json; exit(0 if json.load(sys.stdin).get('processing_status')=='idle' else 1)"; do
  sleep 3
done

# 12. Deploy
mcpheroctl wizard deploy $SERVER_ID --json
# → {"server_url": "/mcp/<server-id>/mcp", "bearer_token": "...", "step": "complete"}

IMPORTANT: deploy returns a relative server_url like /mcp//mcp. Prepend the base domain to get the full URL:

https://api.mcphero.app/mcp/<server-id>/mcp

Server Management

mcpheroctl server list --json [CUSTOMER_ID]  # List all servers
mcpheroctl server get SERVER_ID --json       # Get server details + status
mcpheroctl server update SERVER_ID           # Update name/description
mcpheroctl server delete SERVER_ID --yes     # Delete (irreversible)
mcpheroctl server api-key SERVER_ID --json   # Retrieve bearer token

Polling Pattern

The reliable way to poll is to check processing_status, not setup_status:

until mcpheroctl wizard state $SERVER_ID --json 2>/dev/null | \
  python3 -c "import sys,json; exit(0 if json.load(sys.stdin).get('processing_status')=='idle' else 1)"; do
  sleep 3
done

Connecting a Deployed Server to MCP Clients

After deploy, construct the full server URL:

https://api.mcphero.app{server_url}

Claude Desktop config

{
  "mcpServers": {
    "my-server": {
      "url": "https://api.mcphero.app/mcp/<server-id>/mcp",
      "headers": {
        "Authorization": "Bearer <bearer_token>"
      }
    }
  }
}

Config file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/claude/claude_desktop_config.json

Key Tips

Free tier: Max 5 tools per server. wizard_submit_tools will error if more are selected.

server_id is everything: Save the UUID returned from create_session. Every subsequent call needs it.

Env var format in CLI: --var "UUID=VALUE" — the UUID is the env var's id from list-env-vars, not its name.

Empty env vars: Even if list-env-vars returns [], you must still call submit-env-vars (with no vars) so the backend transitions to the next state.

Regenerate without redeploy: After using wizard_regenerate_tool_code, the code change takes effect immediately for already-deployed servers (the server auto-remounts).

Always use --json: In CLI commands, --json sends structured data to stdout. Without it, human-friendly messages go to stderr and can break piping/parsing.

Exit Codes