loop-mcp

Measured conclusion: Deep-tested. L2 outcome: tools_ok.

15 pay-per-call Bitcoin and developer tools, paid in sats over Lightning (L402).

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Copy this into your MCP client config:

{
  "mcpServers": {
    "loop-mcp": {
      "url": "https://mcp.loopxxi.com/mcp",
      "transport": "streamable-http"
    }
  }
}

Measured tools (15)

• btc_price read-only

  Get the current Bitcoin price in USD and other major currencies. Source: mempool.space. Real-time.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• btc_send_decision read-only

  Returns a composited send-or-wait recommendation for a Bitcoin transaction. Fetches live mempool and fee data, then outputs a machine-actionable verdict (SEND_NOW, WAIT, or URGENT_ONLY) with fee rates in sat/vB, mempool pressure level, and estimated savings if you wait. Ideal for agents that need a single decision call instead of parsing multiple raw mempool endpoints.

  Parameters:

  • urgency — string — How time-sensitive is your transaction? low=economy, medium=default, high=next-block.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• lightning_address_resolve read-only

  Resolve a Lightning Address ([email protected]) to a payable BOLT11 invoice for a given amount. Handles the full LNURL-pay protocol internally. Returns the invoice plus min/max sendable amounts for validation.

  Parameters:

  • address (required) — string — Lightning Address in [email protected] format.
  • amount_sats (required) — integer — Amount you want to send, in satoshis.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• tx_decode_explain read-only

  Fetch a Bitcoin transaction by txid and return a structured, agent-ready summary: type (P2WPKH/P2TR/P2SH/etc.), input/output counts, fees, fee rate in sat/vB, confirmation status, RBF flag, SegWit/Taproot flags, and a one-line agent_summary string ready for LLM context injection. Saves 500-2000 tokens vs parsing raw TX JSON.

  Parameters:

  • txid (required) — string — Bitcoin transaction ID (64 hex characters).

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• optimal_send_window read-only

  Bitcoin transaction timing intelligence. Returns a congestion forecast for the next 1-4h, a recommended UTC send window when fees are projected at/below your target, a fee trajectory (rising/stable/falling) with a calibrated confidence score, next-block minimum fee, confirmation targets for 3/6/144 blocks, and an RBF-viability flag. A synthesis layer above raw fee data — the decision an autonomous payment agent needs before broadcasting. Source: mempool.space.

  Parameters:

  • hours_ahead — integer — How far ahead to search for the optimal window (1-6h, default 4).
  • target_sat_vb — number — Your fee ceiling in sat/vB. The recommended window targets at-or-below this rate. Omit to get the lowest-projected window.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• json_validate read-only

  Validate JSON, identify its root type, and return normalized JSON plus a SHA-256 content hash.

  Parameters:

  • json (required) — string — JSON text to validate, up to 100 KB.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• json_extract read-only

  Extract one value from JSON using a simple dot path with array indexes, for example users[0].email.

  Parameters:

  • json (required) — string — JSON text, up to 100 KB.
  • path (required) — string — Dot path such as user.profile.name or users[0].email.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• csv_to_json read-only

  Convert CSV, TSV, semicolon, or pipe-delimited text into structured JSON with bounded row output.

  Parameters:

  • csv (required) — string — Delimited text, up to 100 KB.
  • header — boolean — Use the first row as object keys. Default true.
  • max_rows — integer — Maximum data rows to return. Default 100.
  • delimiter — string — Delimiter name. Default comma.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• text_analyze read-only

  Return deterministic text statistics, estimated tokens, reading time, and a SHA-256 content hash.

  Parameters:

  • text (required) — string — Text to analyze, up to 100 KB.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• hash_generate read-only

  Generate a SHA-256 or SHA-512 digest in hexadecimal or Base64 form.

  Parameters:

  • text (required) — string — Input text, up to 100 KB.
  • encoding — string — Output encoding. Default hex.
  • algorithm — string — Hash algorithm. Default sha256.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• base64_convert read-only

  Encode UTF-8 text to Base64 or decode Base64 safely, with standard and URL-safe alphabets.

  Parameters:

  • data (required) — string — Text or Base64 data, up to 100 KB.
  • action (required) — string
  • url_safe — boolean — Use the URL-safe alphabet without padding.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• timestamp_convert read-only

  Convert Unix seconds, Unix milliseconds, RFC3339, or ISO dates into normalized UTC timestamp forms.

  Parameters:

  • value (required) — string — Timestamp value.
  • from — string — Input format. Default auto.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• uuid_generate read-only

  Generate one to one hundred cryptographically random RFC 4122 UUID version 4 identifiers.

  Parameters:

  • count — integer — Number of UUIDs. Default 1.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• url_parse read-only

  Parse an HTTP or HTTPS URL into normalized scheme, host, port, path, query, and fragment fields without fetching it.

  Parameters:

  • url (required) — string — Absolute HTTP or HTTPS URL, up to 4,096 characters.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

• jwt_decode read-only

  Decode JWT header and payload claims locally without verifying the signature. The response always marks verification as false.

  Parameters:

  • token (required) — string — JWT compact serialization, up to 20 KB.

  Hints: read-only yes · destructive no · idempotent not declared · open-world yes

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Measured by MCPYP probing. Untested fields are omitted, never estimated. Listing is always free; MCPYP never proxies calls or stores user tokens.