feat(config): make per-turn spend limit user-configurable

src/agent/loop.ts

@@ -17,6 +17,7 @@ import { resetToolSessionState } from '../tools/index.js';
 import { CORE_TOOL_NAMES, dynamicToolsEnabled } from '../tools/tool-categories.js';
 import { createActivateToolCapability } from '../tools/activate.js';
 import { recordUsage } from '../stats/tracker.js';
+import { loadConfig } from '../commands/config.js';
 import { recordSessionUsage } from '../stats/session-tracker.js';
 import { appendAudit, extractLastUserPrompt } from '../stats/audit.js';
 import { estimateCost, OPUS_PRICING } from '../pricing.js';
@@ -546,7 +547,21 @@ export async function interactiveSession(
     let consecutiveTinyResponses = 0;                    // Count of consecutive calls with <10 output tokens
     const MAX_TINY_RESPONSES = 2;                        // Break after N tiny responses — if 2 calls return near-empty, something is wrong
     let turnSpend = 0;                                   // Cost spent this user turn (USD)
-    const MAX_TURN_SPEND_USD = 0.25;                    // Hard circuit breaker per user message (lowered — user wallets are real money)
+    // Hard circuit breaker per user message — defends user wallets against
+    // a runaway model+tool combo on a single prompt. User-overridable via
+    // `franklin config set max-turn-spend-usd <number>`. Explicit "0" or a
+    // negative number disables the cap; a non-numeric / unparseable value
+    // is treated as a typo and falls back to the safe default rather than
+    // silently removing the wallet guard.
+    const turnSpendCap = (() => {
+      const raw = loadConfig()['max-turn-spend-usd'];
+      if (raw == null) return 0.25;
+      const parsed = Number(raw);
+      if (!Number.isFinite(parsed)) return 0.25;   // typo → keep default
+      if (parsed <= 0) return Infinity;            // explicit opt-out
+      return parsed;
+    })();
+    const MAX_TURN_SPEND_USD = turnSpendCap;
 
     // ── Turn analysis (one classifier call, drives routing + prefetch) ──
     // Single LLM pass that answers every routing-adjacent question the

src/commands/config.ts

@@ -14,6 +14,7 @@ const VALID_KEYS = [
   'smart-routing',
   'permission-mode',
   'max-turns',
+  'max-turn-spend-usd',
   'auto-compact',
   'session-save',
   'debug',
@@ -29,6 +30,13 @@ export interface AppConfig {
   'smart-routing'?: string;
   'permission-mode'?: string;
   'max-turns'?: string;
+  /**
+   * Hard per-turn spend ceiling in USD (default $0.25). Numeric string,
+   * e.g. "0.5" or "2". Set to "0" to disable the cap. The agent loop
+   * stops a turn the moment cumulative cost crosses this threshold,
+   * preventing a runaway model + tool combo from draining the wallet.
+   */
+  'max-turn-spend-usd'?: string;
   'auto-compact'?: string;
   'session-save'?: string;
   'debug'?: string;