k402-mcp — pay-per-call APIs for AI agents, settled in Kaspa

An MCP server that gives any agent (Claude Code, Claude Desktop, agent SDKs) a catalog of agent-payable APIs: text tools (summarize, schema-guaranteed extraction, classify, rewrite), web reading, embeddings + semantic search, live Kaspa mainnet chain data, GPU model tiers, covenants-as-a-service (compile/derive/inspect/build/check/broadcast Silverscript covenants), and RISC Zero attestation-as-a-service (upload a guest, preflight for a cycle-exact quote, prove, verify). No account, no card, no API key — the agent opens a session, gets a personal KAS deposit address, and every call meters against the prepaid balance. Prices are USD-pegged, fractions of a cent per call, settled on Kaspa L1 (sub-second, ~zero fees).

The payment loop is agent-native: an unfunded call returns instructions ("send KAS to this address, this call costs X"), so an agent can discover the service, learn how to pay, and use it autonomously — the x402 idea, on Kaspa.

Hosted endpoint — zero install

The same server runs hosted at the public gateway (streamable HTTP):

https://x402-compute.68cxgfyr0.workers.dev/mcp

Claude Code:

claude mcp add --transport http k402 https://x402-compute.68cxgfyr0.workers.dev/mcp

Hosted sessions are per-connection: open_session binds the payment session to your MCP connection and returns the key — save it, and re-attach with use_session(<key>) after a reconnect. Nothing is shared between connections.

Install (local stdio)

pip install k402-mcp

Claude Code:

claude mcp add k402 -- k402-mcp

Claude Desktop / generic MCP config:

{ "mcpServers": { "k402": { "command": "k402-mcp" } } }

Env (all optional): K402_GATEWAY (defaults to the public gateway), K402_SESSION (pin a funded session key), K402_STATE (where the auto-opened session persists, default ~/.k402/session.json).

Use

1. catalog — see every service and its live KAS/USD price (free)
2. open_session — get a session + personal Kaspa mainnet deposit address (free); fund it from any wallet (min 0.25 KAS — confirmed in seconds)
3. Call anything: summarize, extract, classify, rewrite, read_url, embed_text, search_index/search_query, kaspa_balance, kaspa_utxos, kaspa_tx_status, kaspa_fee_estimate, kaspa_network, generate (tiers: chat / llama / reason / think / code / kaspa-expert), covenant_compile/covenant_address/covenant_utxos/covenant_build/covenant_check/covenant_broadcast, prove_guest_upload/prove_preflight/prove_submit/job_status/job_result/attest_verify, payment_options, pay_per_call
4. session_status — watch the balance draw down (free)

New here? Start with open_session — one funded deposit address, and every call meters against it. That's the whole loop. The other schemes (per-call coins, or trustless payment channels) are for when you want them; payment_options explains each.

Trustless payment channels (kaspa-channel)

Where the gateway offers it, channel_config/channel_status expose a covenant payment channel: your KAS sits in a Kaspa L1 covenant (not the merchant's wallet), and you pay per call with signed vouchers — the merchant can only ever claim what you signed, and you reclaim the rest. Opening and funding a channel needs your Kaspa key, so that part runs in the k402 Python client (k402.channel); these MCP tools cover discovery and status.

Example, in Claude Code after claude mcp add:

"Use the k402 tools to check the current Kaspa network status and summarize https://kaspa.org"

The first call returns how-to-pay instructions; fund the deposit address it gives you and retry.

Notes & honest caveats

• Prototype. Payments settle either custodial-prepaid (sessions) or trustlessly via kaspa-channel covenant payment channels (live on mainnet, covenant unaudited — channel sizes are capped). Keep balances small: a few KAS covers thousands of calls.
• Paid tools return payment_required + instructions instead of failing opaquely.
• The gateway rate-limits per IP; prices float with KAS/USD, so catalog shows current numbers.
• Need KAS? Any exchange or wallet works — deposits are plain mainnet transfers.

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mcp-name: io.github.Kali123411/k402

MIT © Kaspa Lab