fix: add context monitor cost warning opt-out

tests/hooks/ecc-context-monitor.test.js

@@ -5,8 +5,12 @@
  */
 
 const assert = require('assert');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
 
-const { run, evaluateConditions, detectLoop, severityLabel } = require('../../scripts/hooks/ecc-context-monitor');
+const { run, evaluateConditions, detectLoop, severityLabel, costWarningsEnabled } = require('../../scripts/hooks/ecc-context-monitor');
+const { getBridgePath, writeBridgeAtomic } = require('../../scripts/lib/session-bridge');
 
 // Test helper
 function test(name, fn) {
@@ -21,6 +25,18 @@ function test(name, fn) {
   }
 }
 
+function withEnv(name, value, fn) {
+  const original = process.env[name];
+  try {
+    if (value === undefined) delete process.env[name];
+    else process.env[name] = value;
+    return fn();
+  } finally {
+    if (original === undefined) delete process.env[name];
+    else process.env[name] = original;
+  }
+}
+
 function runTests() {
   console.log('\n=== Testing ecc-context-monitor.js ===\n');
 
@@ -113,6 +129,53 @@ function runTests() {
     passed++;
   else failed++;
 
+  if (
+    test('cost warnings can be suppressed without hiding context warnings', () => {
+      const warnings = evaluateConditions({ total_cost_usd: 55, context_remaining_pct: 20 }, { costWarnings: false });
+      assert.strictEqual(warnings.find(w => w.type === 'cost'), undefined);
+      const ctx = warnings.find(w => w.type === 'context');
+      assert.ok(ctx, 'Expected context warning to remain enabled');
+      assert.strictEqual(ctx.severity, 3);
+    })
+  )
+    passed++;
+  else failed++;
+
+  if (
+    test('ECC_CONTEXT_MONITOR_COST_WARNINGS=off disables only run-time cost warnings', () => {
+      const sessionId = `ctx-monitor-cost-off-${process.pid}-${Date.now()}`;
+      const input = JSON.stringify({ session_id: sessionId, tool_name: 'Bash' });
+      const warnPath = path.join(os.tmpdir(), `ecc-ctx-warn-${sessionId}.json`);
+      try {
+        writeBridgeAtomic(sessionId, {
+          context_remaining_pct: 20,
+          total_cost_usd: 55,
+          last_timestamp: new Date().toISOString()
+        });
+        const result = withEnv('ECC_CONTEXT_MONITOR_COST_WARNINGS', 'off', () => JSON.parse(run(input)));
+        const message = result.hookSpecificOutput.additionalContext;
+        assert.ok(message.includes('CONTEXT CRITICAL'), 'Expected context warning to remain');
+        assert.ok(!message.includes('COST CRITICAL'), 'Expected cost warning to be suppressed');
+      } finally {
+        fs.rmSync(getBridgePath(sessionId), { force: true });
+        fs.rmSync(warnPath, { force: true });
+      }
+    })
+  )
+    passed++;
+  else failed++;
+
+  if (
+    test('cost warning env defaults on and accepts false-like values', () => {
+      assert.strictEqual(withEnv('ECC_CONTEXT_MONITOR_COST_WARNINGS', undefined, () => costWarningsEnabled()), true);
+      assert.strictEqual(withEnv('ECC_CONTEXT_MONITOR_COST_WARNINGS', 'false', () => costWarningsEnabled()), false);
+      assert.strictEqual(withEnv('ECC_CONTEXT_MONITOR_COST_WARNINGS', '0', () => costWarningsEnabled()), false);
+      assert.strictEqual(withEnv('ECC_CONTEXT_MONITOR_COST_WARNINGS', 'yes', () => costWarningsEnabled()), true);
+    })
+  )
+    passed++;
+  else failed++;
+
   // evaluateConditions — scope warnings
   console.log('\nevaluateConditions (scope):');