Fetch a URL that may require a Bitcoin Lightning payment (L402 protocol). Side effect: deducts sats from the session budget when a payment is required — check l402_balance first if budget is limited. Flow: sends request → if 402 received, pays the Lightning invoice (1 attempt) → retries once with payment proof → returns response body as text. Fails with error if: budget is exhausted, URL is unreachable, or the Lightning payment fails. Do NOT use for regular (non-L402) URLs — use a standard fetch tool instead. Do NOT use if l402_balance shows 0 sats remaining.

Returns the remaining Bitcoin Lightning budget for this MCP session. Use this before calling l402_fetch to confirm you have enough sats — avoids wasted attempts when budget is exhausted. Returns: ' sats remaining of total (spent: sats)'. Read-only — does not trigger any payment or side effect. Budget is set at server startup via BUDGET_SATS (default: 1000 sats ≈ $0.60); to increase it, restart the MCP server.

Returns a full audit of all Bitcoin Lightning payments made in this MCP session. Includes: total sats spent, remaining budget, sats spent per domain, and chronological transaction list (timestamp + sats + URL). Use this instead of l402_balance when you need to know which APIs were called and how much each cost, not just the remaining balance. Read-only — does not trigger any payment or side effect. Returns '(none yet)' for domains and transactions if no payments have been made this session.

Returns the session budget cap configured at startup (via BUDGET_SATS env var). Use this to confirm what hard spending limit is in effect — useful at the start of a session before making any API calls. Read-only: this tool CANNOT set or change the budget at runtime. To raise or lower the cap, stop and restart the MCP server with a different BUDGET_SATS value. For remaining balance during a session, use l402_balance instead.