Claude Code + SingIt MCP in 60 seconds

Start with no key and no wallet. Add your own limits for paid answers.

1. Connect without a key

claude mcp add --transport http --scope user singit https://app.singitai.app/mcp
claude mcp list

Expected output:

singit: https://app.singitai.app/mcp (HTTP) - ✔ Connected

Checked on 2 November 2026 with Claude Code 2.1.310 and a clean config. Inside a Claude Code session, /mcp shows the same server.

2. Ask for a free answer

Ask Claude Code:

Use the SingIt chat_free tool to explain x402 in two sentences.

chat_free uses a free model (default free/deepseek-v4.1-flash), up to 400 tokens. It reports billing.remainingToday, billing.resetsAt and a hint to drop the free/ prefix to pay.

Free answers are a small daily allowance counted per network, with a shared daily budget that can run out for the day.

3. Add paid answers with limits you set

Create an MCP key in the SingIt app, Settings → API keys. See MCP key setup for top-up and daily and per-request limits: the wallet signs them.

Export the variable before starting Claude Code, then re-add the server:

export SINGIT_API_KEY=sk_singit_...
claude mcp remove singit --scope user
claude mcp add --transport http --scope user singit https://app.singitai.app/mcp --header 'Authorization: Bearer ${SINGIT_API_KEY}'

Single quotes stop the shell expanding the reference; Claude Code expands it when it connects. If unset, Claude Code warns Missing environment variables: SINGIT_API_KEY.

Use the SingIt chat tool with model <id from list_models> ...

Use get_limits and get_receipts to see what is left and what was charged.

What the limits mean

Troubleshooting

Not connected: run claude mcp list, then use /mcp to reconnect.
401: wrong or revoked key. A key typo is never silently treated as keyless.
Free allowance used up: use a key or come back after midnight UTC.
MCP rate limit: 60 requests a minute per key (per address without a key).

Codex users: codex mcp add singit --url https://app.singitai.app/mcp.