k402

Agent-payable APIs on Kaspa: LLMs, chain data, covenants, zk proofs — pay per call, no API key

Should I use this

Quality & Safety

A
Description quality
95%
Schema completeness
70%
Naming quality
83%
Poisoning risk
100%
Permission match
100%
Protocol compliance
100%

Findings (3)

  • LOWTool 'extract' description lacks action verbin extract
  • LOWTool 'embed_text' description lacks action verbin embed_text
  • LOWTool 'kaspa_fee_estimate' description lacks action verbin kaspa_fee_estimate

Based on automated analysis of tool definitions and protocol compliance.

Context Cost

~4,137Tokens (tool definitions)
~574 BTypical response size
Significant attention impact (3.23% of 128k context)

This is the approximate number of tokens consumed each time the server's tools are loaded into a model's context. Higher counts reduce the attention available for other tasks.

Install

One-Click Install

Add this to your `claude_desktop_config.json` file:

{
  "mcpServers": {
    "k402": {
      "command": "uvx",
      "args": [
        "k402-mcp"
      ]
    }
  }
}

Runnable packages

pypik402-mcp0.7.0stdio

Remote endpoints

https://x402-compute.68cxgfyr0.workers.dev/mcpstreamable-http

What it can do

Tool inventory

Tools (36)

🟢 Read-only🟡 Write🔴 Delete⚪ Unknown
🟢catalog

List every service this gateway sells (text tools, Kaspa chain data, LLM tiers) with live prices in KAS and USD. Free. Start here to see what's available and what calls cost.

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "catalogArguments"
}
🟡open_session

Open a prepaid payment session: returns a session key and a personal Kaspa MAINNET deposit address. Send KAS to the address from any wallet (min 0.25 KAS); confirmed deposits become spendable balance within seconds and every paid tool call meters against it. Free. The session is saved locally so subsequent calls use it automatically.

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "open_sessionArguments"
}
⚪use_session(session)

Attach an existing k402 session key (from a previous open_session) so paid calls meter against its balance — use after reconnecting to the hosted endpoint, or to carry one funded session across clients. Returns the session's current balance. Free.

Input Schema

{
  "type": "object",
  "properties": {
    "session": {
      "title": "Session",
      "type": "string"
    }
  },
  "required": [
    "session"
  ],
  "title": "use_sessionArguments"
}
🟢session_status

Check the current payment session: deposit address, deposited / spent / remaining KAS. Free.

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "session_statusArguments"
}
🟢registry_search(capability, max_price_usd, min_reputation_kas, limit)

Discover providers in the k402 service exchange — an open marketplace of agent-payable services, each settled trustlessly over a Kaspa payment channel directly with the provider (no custodian). Filter by capability (e.g. 'summarize', 'llm:reason', 'zk-prove'), max USD price, and minimum reputation (settled KAS volume, chain-verified). Results are ranked reputation-first. Free. Returns each provider's endpoint, payee pubkey, price, channel terms, and reputation.

Input Schema

{
  "type": "object",
  "properties": {
    "capability": {
      "default": "",
      "title": "Capability",
      "type": "string"
    },
    "max_price_usd": {
      "default": 0,
      "title": "Max Price Usd",
      "type": "number"
    },
    "min_reputation_kas": {
      "default": 0,
      "title": "Min Reputation Kas",
      "type": "number"
    },
    "limit": {
      "default": 20,
      "title": "Limit",
      "type": "integer"
    }
  },
  "title": "registry_searchArguments"
}
⚪registry_provider(payee_pubkey)

Full detail on one provider in the service exchange by its payee pubkey: every service it lists, its chain-verified reputation (settled KAS volume + settlement count), and its payee address. Free.

Input Schema

{
  "type": "object",
  "properties": {
    "payee_pubkey": {
      "title": "Payee Pubkey",
      "type": "string"
    }
  },
  "required": [
    "payee_pubkey"
  ],
  "title": "registry_providerArguments"
}
⚪channel_config

Parameters for opening a kaspa-channel — a covenant-enforced payment channel that settles per-call vouchers on Kaspa L1 with NO custodian (the trustless alternative to a prepaid session). Returns the payee pubkey, min/max channel size, required expiry lead, and maxfee. Free. Opening a channel means funding the channel covenant on-chain (payer holds the key), then paying per call with signed vouchers — use the `k402` Python client (`pip install k402`, k402.channel) to build the covenant and sign vouchers, since that flow needs your Kaspa key. Returns {error} if this gateway hasn't enabled the (experimental) channel rail.

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "channel_configArguments"
}
⚪channel_status(channel_id)

Status of a kaspa-channel by its channel id (covenant id): funded value, amount spent via vouchers, remaining, expiry, and whether it has been closed on-chain. Free.

Input Schema

{
  "type": "object",
  "properties": {
    "channel_id": {
      "title": "Channel Id",
      "type": "string"
    }
  },
  "required": [
    "channel_id"
  ],
  "title": "channel_statusArguments"
}
⚪payment_options

Which coins and schemes this gateway accepts for payment. Free. Ways to pay any paid tool: a prepaid KAS session (open_session — simplest, no per-call step); per-call in any listed coin (pay the offer a 402 returns, then pay_per_call); or, where the experimental 'kaspa-channel' scheme is offered, a covenant payment channel that settles per-call vouchers on L1 with no custodian (see channel_config). Coins may include Kaspa, Pearl, BTC, LTC, DOGE, BCH, DASH, and EVM assets (ETC, ETH, USDC, USDT).

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "payment_optionsArguments"
}
⚪pay_per_call(endpoint, request_body, scheme, payment_id, txid)

Complete a PER-CALL coin payment. After a paid tool returns a 402 with pay_per_call_offers, pay one offer on-chain from your own wallet, then call this with the 402's `endpoint` and `request_body`, the chosen offer's `scheme` and `payment_id`, and your payment `txid`. The gateway verifies the payment landed and returns the tool's real result. (Alternative to a prepaid session — use this when you'd rather pay each call directly in a specific coin.)

Input Schema

{
  "type": "object",
  "properties": {
    "endpoint": {
      "title": "Endpoint",
      "type": "string"
    },
    "request_body": {
      "additionalProperties": true,
      "title": "Request Body",
      "type": "object"
    },
    "scheme": {
      "title": "Scheme",
      "type": "string"
    },
    "payment_id": {
      "title": "Payment Id",
      "type": "string"
    },
    "txid": {
      "title": "Txid",
      "type": "string"
    }
  },
  "required": [
    "endpoint",
    "request_body",
    "scheme",
    "payment_id",
    "txid"
  ],
  "title": "pay_per_callArguments"
}
⚪summarize(text, url, max_words)

Summarize text or a public URL in at most max_words. Paid (~$0.001 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "text": {
      "default": "",
      "title": "Text",
      "type": "string"
    },
    "url": {
      "default": "",
      "title": "Url",
      "type": "string"
    },
    "max_words": {
      "default": 150,
      "title": "Max Words",
      "type": "integer"
    }
  },
  "title": "summarizeArguments"
}
🟢extract(text, schema, instruction)

Extract structured data from text as JSON guaranteed to match your JSON schema (schema-constrained decoding, not best-effort). Paid (~$0.0015 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "text": {
      "title": "Text",
      "type": "string"
    },
    "schema": {
      "additionalProperties": true,
      "title": "Schema",
      "type": "object"
    },
    "instruction": {
      "default": "",
      "title": "Instruction",
      "type": "string"
    }
  },
  "required": [
    "text",
    "schema"
  ],
  "title": "extractArguments"
}
⚪rewrite(text, instruction)

Rewrite text per an instruction (tone, format, length...). Paid (~$0.001 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "text": {
      "title": "Text",
      "type": "string"
    },
    "instruction": {
      "title": "Instruction",
      "type": "string"
    }
  },
  "required": [
    "text",
    "instruction"
  ],
  "title": "rewriteArguments"
}
⚪classify(text, labels, multi)

Classify text into one (or multiple, if multi=true) of 2-32 labels; the result is constrained to your label set. Paid (~$0.0003 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "text": {
      "title": "Text",
      "type": "string"
    },
    "labels": {
      "items": {
        "type": "string"
      },
      "title": "Labels",
      "type": "array"
    },
    "multi": {
      "default": false,
      "title": "Multi",
      "type": "boolean"
    }
  },
  "required": [
    "text",
    "labels"
  ],
  "title": "classifyArguments"
}
🟢read_url(url, distill)

Fetch a public web page and return its title + clean markdown; distill=true adds key-fact bullets. Useful when you have no web access of your own. Paid (~$0.0012 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "url": {
      "title": "Url",
      "type": "string"
    },
    "distill": {
      "default": false,
      "title": "Distill",
      "type": "boolean"
    }
  },
  "required": [
    "url"
  ],
  "title": "read_urlArguments"
}
⚪embed_text(texts)

Embed up to 64 texts (768-dim vectors, nomic-embed-text). Paid (~$0.0003 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "texts": {
      "items": {
        "type": "string"
      },
      "title": "Texts",
      "type": "array"
    }
  },
  "required": [
    "texts"
  ],
  "title": "embed_textArguments"
}
🟢search_index(collection, documents, replace)

Store documents [{id, text, meta?}] in a named server-side collection for semantic search. Use an unguessable collection name and keep it secret. Paid (~$0.0015 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "collection": {
      "title": "Collection",
      "type": "string"
    },
    "documents": {
      "items": {
        "additionalProperties": true,
        "type": "object"
      },
      "title": "Documents",
      "type": "array"
    },
    "replace": {
      "default": false,
      "title": "Replace",
      "type": "boolean"
    }
  },
  "required": [
    "collection",
    "documents"
  ],
  "title": "search_indexArguments"
}
🟢search_query(collection, q, top_k)

Semantic-search a collection you indexed earlier; returns top-k matches with scores. Paid (~$0.0003 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "collection": {
      "title": "Collection",
      "type": "string"
    },
    "q": {
      "title": "Q",
      "type": "string"
    },
    "top_k": {
      "default": 5,
      "title": "Top K",
      "type": "integer"
    }
  },
  "required": [
    "collection",
    "q"
  ],
  "title": "search_queryArguments"
}
⚪kaspa_balance(address)

Balance of any Kaspa MAINNET address, straight from a node (no indexer, no API key). Paid (~$0.00015 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "address": {
      "title": "Address",
      "type": "string"
    }
  },
  "required": [
    "address"
  ],
  "title": "kaspa_balanceArguments"
}
🟡kaspa_utxos(address)

UTXO set of a Kaspa mainnet address, including scriptPublicKey and covenant_id where set. Paid (~$0.0003 in KAS).

Input Schema

{
  "type": "object",
  "properties": {
    "address": {
      "title": "Address",
      "type": "string"
    }
  },
  "required": [
    "address"
  ],
  "title": "kaspa_utxosArguments"
}
⚪kaspa_tx_status(txid)

Mempool status of a Kaspa transaction. Absent from mempool means accepted-or-unknown — confirm acceptance by checking one of its outputs with kaspa_utxos. Paid (~$0.00015).

Input Schema

{
  "type": "object",
  "properties": {
    "txid": {
      "title": "Txid",
      "type": "string"
    }
  },
  "required": [
    "txid"
  ],
  "title": "kaspa_tx_statusArguments"
}
⚪kaspa_fee_estimate

Current Kaspa mainnet feerate buckets (sompi per gram of tx mass). Paid (~$0.00015).

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "kaspa_fee_estimateArguments"
}
⚪kaspa_network

Kaspa mainnet status: DAA score, block count, difficulty, node sync state. Paid (~$0.00015 in KAS).

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "kaspa_networkArguments"
}
⚪generate(prompt, tier, system, max_tokens)

Run a prompt on a GPU model tier: 'chat' (fast 7B, ~$0.0015), 'llama' (budget 8B, ~$0.0008), 'reason' (35B, ~$0.004), 'think' (deep chain-of-thought 35B MoE, ~$0.004), 'code' (coder model, ~$0.0025), or 'kaspa-expert' (RAG-grounded, current Kaspa knowledge, ~$0.0015). Returns the completion text.

Input Schema

{
  "type": "object",
  "properties": {
    "prompt": {
      "title": "Prompt",
      "type": "string"
    },
    "tier": {
      "default": "chat",
      "title": "Tier",
      "type": "string"
    },
    "system": {
      "default": "",
      "title": "System",
      "type": "string"
    },
    "max_tokens": {
      "default": 512,
      "title": "Max Tokens",
      "type": "integer"
    }
  },
  "required": [
    "prompt"
  ],
  "title": "generateArguments"
}
⚪covenant_compile(source, constructor_args)

Compile a Silverscript covenant to script hex, ABI, hardened template hash, and its P2SH address on each network. constructor_args is the silverc ctor JSON (e.g. [{"kind":"int","data":7}]). Paid (~$0.002). NOTE: 'compiles' ≠ proven on-chain.

Input Schema

{
  "type": "object",
  "properties": {
    "source": {
      "title": "Source",
      "type": "string"
    },
    "constructor_args": {
      "default": null,
      "items": {},
      "title": "Constructor Args",
      "type": "array"
    }
  },
  "required": [
    "source"
  ],
  "title": "covenant_compileArguments"
}
⚪covenant_address(script_hex, network)

Derive the covenant P2SH address for a compiled script on 'mainnet' or 'testnet-10'. Paid (~$0.0003).

Input Schema

{
  "type": "object",
  "properties": {
    "script_hex": {
      "title": "Script Hex",
      "type": "string"
    },
    "network": {
      "default": "mainnet",
      "title": "Network",
      "type": "string"
    }
  },
  "required": [
    "script_hex"
  ],
  "title": "covenant_addressArguments"
}
🟡covenant_utxos(address, network, covenant_id)

Live UTXO set locked under a covenant address (covenant state inspection), from the node. Optionally filter by covenant_id. Paid (~$0.0003).

Input Schema

{
  "type": "object",
  "properties": {
    "address": {
      "title": "Address",
      "type": "string"
    },
    "network": {
      "default": "mainnet",
      "title": "Network",
      "type": "string"
    },
    "covenant_id": {
      "default": "",
      "title": "Covenant Id",
      "type": "string"
    }
  },
  "required": [
    "address"
  ],
  "title": "covenant_utxosArguments"
}
🟢covenant_build(inputs, outputs, network, lock_time, payload_hex)

Assemble a covenant spend tx. Each input: {txid, index, entry, compute_budget?, and either sigscript:{source,decl,args,is_leader?} to build a covenant sigscript server-side, or omit sigscript for a P2PK input you sign locally}. Each output: {amount, address|script_public_key_hex, covenant?:{authorizing_input,covenant_id}}. Returns the tx, a broadcast-ready rpc_transaction, fee accounting, and (if fully authorized) a pre-verify. We never sign. Paid (~$0.001).

Input Schema

{
  "type": "object",
  "properties": {
    "inputs": {
      "items": {},
      "title": "Inputs",
      "type": "array"
    },
    "outputs": {
      "items": {},
      "title": "Outputs",
      "type": "array"
    },
    "network": {
      "default": "mainnet",
      "title": "Network",
      "type": "string"
    },
    "lock_time": {
      "default": 0,
      "title": "Lock Time",
      "type": "integer"
    },
    "payload_hex": {
      "default": "",
      "title": "Payload Hex",
      "type": "string"
    }
  },
  "required": [
    "inputs",
    "outputs"
  ],
  "title": "covenant_buildArguments"
}
🟢covenant_check(transaction, entries)

Local txscript pre-verify of a signed covenant tx BEFORE broadcast — catches script failures that would otherwise cost you a broadcast. 'entries' are the spent UTXOs (covenant_utxos output plugs in directly). Returns {all_ok, inputs:[{index, ok, error?}]}. Paid (~$0.0005).

Input Schema

{
  "type": "object",
  "properties": {
    "transaction": {
      "additionalProperties": true,
      "title": "Transaction",
      "type": "object"
    },
    "entries": {
      "items": {},
      "title": "Entries",
      "type": "array"
    }
  },
  "required": [
    "transaction",
    "entries"
  ],
  "title": "covenant_checkArguments"
}
🟢covenant_broadcast(transaction, network)

Broadcast a signed covenant tx (RpcTransaction JSON from covenant_build). MAINNET moves real KAS — run covenant_check first. Paid (~$0.0003).

Input Schema

{
  "type": "object",
  "properties": {
    "transaction": {
      "additionalProperties": true,
      "title": "Transaction",
      "type": "object"
    },
    "network": {
      "default": "mainnet",
      "title": "Network",
      "type": "string"
    }
  },
  "required": [
    "transaction"
  ],
  "title": "covenant_broadcastArguments"
}
🟡prove_guest_upload(program_b64)

Upload a RISC Zero program binary (the .bin risc0-build emits, base64) once; returns its content-addressed image_id (also the verification key), reusable across proofs. Paid (~$0.01).

Input Schema

{
  "type": "object",
  "properties": {
    "program_b64": {
      "title": "Program B64",
      "type": "string"
    }
  },
  "required": [
    "program_b64"
  ],
  "title": "prove_guest_uploadArguments"
}
🟢prove_preflight(image_id, input_b64)

Execute a guest WITHOUT proving: exact cycle count + a signed price quote {total_cycles, price_kas, quote_id, quote_expires}. Run this first — proving cost scales with cycles by orders of magnitude. Paid (~$0.002).

Input Schema

{
  "type": "object",
  "properties": {
    "image_id": {
      "title": "Image Id",
      "type": "string"
    },
    "input_b64": {
      "default": "",
      "title": "Input B64",
      "type": "string"
    }
  },
  "required": [
    "image_id"
  ],
  "title": "prove_preflightArguments"
}
🟡prove_submit(image_id, input_b64, quote_id, max_kas)

Queue a proving job -> {job_id, cost_kas}. Pass quote_id (from prove_preflight; charged the quote) or max_kas (skip preflight; priced on actual cycles, refuses if over the cap). Then poll job_status and fetch job_result. Paid: the proof's cycle-based price (dynamic).

Input Schema

{
  "type": "object",
  "properties": {
    "image_id": {
      "title": "Image Id",
      "type": "string"
    },
    "input_b64": {
      "default": "",
      "title": "Input B64",
      "type": "string"
    },
    "quote_id": {
      "default": "",
      "title": "Quote Id",
      "type": "string"
    },
    "max_kas": {
      "default": 0,
      "title": "Max Kas",
      "type": "number"
    }
  },
  "required": [
    "image_id"
  ],
  "title": "prove_submitArguments"
}
⚪job_status(job_id)

Poll a proving job: queued/running/done/failed, queue position, cost. Free.

Input Schema

{
  "type": "object",
  "properties": {
    "job_id": {
      "title": "Job Id",
      "type": "string"
    }
  },
  "required": [
    "job_id"
  ],
  "title": "job_statusArguments"
}
🟢job_result(job_id)

Fetch a finished proving job's result {image_id, total_cycles, journal_b64, receipt_b64}. 404 until done; results kept 24h. Free.

Input Schema

{
  "type": "object",
  "properties": {
    "job_id": {
      "title": "Job Id",
      "type": "string"
    }
  },
  "required": [
    "job_id"
  ],
  "title": "job_resultArguments"
}
🟢attest_verify(receipt_b64, image_id)

Verify a RISC Zero receipt against an image_id -> {valid, journal_b64}. Anyone can check an attestation without trusting the prover. Paid (~$0.0002).

Input Schema

{
  "type": "object",
  "properties": {
    "receipt_b64": {
      "title": "Receipt B64",
      "type": "string"
    },
    "image_id": {
      "title": "Image Id",
      "type": "string"
    }
  },
  "required": [
    "receipt_b64",
    "image_id"
  ],
  "title": "attest_verifyArguments"
}

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