diff --git a/hooks/gsd-check-update.js b/hooks/gsd-check-update.js
index 6ee97fd2..b109c905 100755
--- a/hooks/gsd-check-update.js
+++ b/hooks/gsd-check-update.js
@@ -19,7 +19,7 @@ function detectConfigDir(baseDir) {
   if (envDir && fs.existsSync(path.join(envDir, 'get-shit-done', 'VERSION'))) {
     return envDir;
   }
-  for (const dir of ['.config/kilo', '.kilo', '.config/opencode', '.opencode', '.gemini', '.claude']) {
+  for (const dir of ['.claude', '.gemini', '.config/kilo', '.kilo', '.config/opencode', '.opencode']) {
     if (fs.existsSync(path.join(baseDir, dir, 'get-shit-done', 'VERSION'))) {
       return path.join(baseDir, dir);
     }
diff --git a/tests/check-update-config-dir.test.cjs b/tests/check-update-config-dir.test.cjs
new file mode 100644
index 00000000..93e4453b
--- /dev/null
+++ b/tests/check-update-config-dir.test.cjs
@@ -0,0 +1,149 @@
+/**
+ * Regression test for #1860: detectConfigDir in gsd-check-update.js should
+ * prioritize .claude over .config/opencode so that Claude Code sessions
+ * don't report false "update available" warnings when an older OpenCode
+ * install exists alongside a newer Claude Code install.
+ */
+
+'use strict';
+
+const { describe, test, beforeEach, afterEach } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+const { execFileSync } = require('child_process');
+
+const CHECK_UPDATE_PATH = path.join(__dirname, '..', 'hooks', 'gsd-check-update.js');
+
+// ─── Static source-order assertion ──────────────────────────────────────────
+
+describe('detectConfigDir search order (#1860)', () => {
+  test('.claude appears before .config/opencode in the search array', () => {
+    const content = fs.readFileSync(CHECK_UPDATE_PATH, 'utf8');
+
+    // Extract the search order array from the for..of loop in detectConfigDir
+    const arrayMatch = content.match(/for\s*\(const dir of\s*\[([^\]]+)\]/);
+    assert.ok(arrayMatch, 'should find the for..of search array in detectConfigDir');
+
+    const arrayLiteral = arrayMatch[1];
+    const entries = arrayLiteral.match(/'([^']+)'/g).map(s => s.replace(/'/g, ''));
+
+    const claudeIndex = entries.indexOf('.claude');
+    const openCodeIndex = entries.indexOf('.config/opencode');
+
+    assert.ok(claudeIndex !== -1, '.claude must be in the search array');
+    assert.ok(openCodeIndex !== -1, '.config/opencode must be in the search array');
+    assert.ok(
+      claudeIndex < openCodeIndex,
+      [
+        '.claude must appear BEFORE .config/opencode in the search array.',
+        `Got order: ${entries.join(', ')}`,
+        `.claude is at index ${claudeIndex}, .config/opencode is at index ${openCodeIndex}.`,
+      ].join(' ')
+    );
+  });
+});
+
+// ─── Integration: hook picks the .claude version when both dirs exist ────────
+
+describe('detectConfigDir runtime behavior (#1860)', () => {
+  let tmpHome;
+
+  beforeEach(() => {
+    tmpHome = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-test-home-'));
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpHome, { recursive: true, force: true });
+  });
+
+  test('returns .claude config dir when both .claude and .config/opencode exist', () => {
+    // Simulate OpenCode install with OLDER version
+    const openCodeVersionDir = path.join(tmpHome, '.config', 'opencode', 'get-shit-done');
+    fs.mkdirSync(openCodeVersionDir, { recursive: true });
+    fs.writeFileSync(path.join(openCodeVersionDir, 'VERSION'), '1.0.0\n');
+
+    // Simulate Claude Code install with NEWER version
+    const claudeVersionDir = path.join(tmpHome, '.claude', 'get-shit-done');
+    fs.mkdirSync(claudeVersionDir, { recursive: true });
+    fs.writeFileSync(path.join(claudeVersionDir, 'VERSION'), '1.32.0\n');
+
+    // Run the hook script with our fake HOME. It will error when trying to spawn
+    // the background child (npm view will fail in test env) but that's OK — we
+    // only care about which VERSION file path it computes. We extract that by
+    // injecting a quick wrapper that calls detectConfigDir and logs the result
+    // before the rest of the script runs.
+    //
+    // Strategy: extract detectConfigDir source from the hook and evaluate it
+    // in a small test harness that uses our fake HOME.
+
+    const hookSource = fs.readFileSync(CHECK_UPDATE_PATH, 'utf8');
+
+    // Extract detectConfigDir function body (from 'function detectConfigDir' to the closing brace)
+    const fnMatch = hookSource.match(/(function detectConfigDir\(baseDir\)\s*\{[\s\S]*?\n\})/);
+    assert.ok(fnMatch, 'should be able to extract detectConfigDir function from hook source');
+    const fnSource = fnMatch[1];
+
+    // Build a test harness script that calls detectConfigDir with our fake home
+    const testScript = [
+      "'use strict';",
+      "const fs = require('fs');",
+      "const path = require('path');",
+      fnSource,
+      `const result = detectConfigDir(${JSON.stringify(tmpHome)});`,
+      "process.stdout.write(result);",
+    ].join('\n');
+
+    const result = execFileSync(process.execPath, ['-e', testScript], {
+      encoding: 'utf8',
+    });
+
+    const expectedDir = path.join(tmpHome, '.claude');
+    assert.strictEqual(
+      result.trim(),
+      expectedDir,
+      [
+        'detectConfigDir should return .claude when both .claude and .config/opencode have VERSION files.',
+        `Expected: ${expectedDir}`,
+        `Got: ${result.trim()}`,
+      ].join('\n')
+    );
+  });
+
+  test('falls back to .config/opencode when .claude does not exist', () => {
+    // Only OpenCode installed
+    const openCodeVersionDir = path.join(tmpHome, '.config', 'opencode', 'get-shit-done');
+    fs.mkdirSync(openCodeVersionDir, { recursive: true });
+    fs.writeFileSync(path.join(openCodeVersionDir, 'VERSION'), '1.0.0\n');
+
+    const hookSource = fs.readFileSync(CHECK_UPDATE_PATH, 'utf8');
+    const fnMatch = hookSource.match(/(function detectConfigDir\(baseDir\)\s*\{[\s\S]*?\n\})/);
+    assert.ok(fnMatch, 'should be able to extract detectConfigDir function from hook source');
+    const fnSource = fnMatch[1];
+
+    const testScript = [
+      "'use strict';",
+      "const fs = require('fs');",
+      "const path = require('path');",
+      fnSource,
+      `const result = detectConfigDir(${JSON.stringify(tmpHome)});`,
+      "process.stdout.write(result);",
+    ].join('\n');
+
+    const result = execFileSync(process.execPath, ['-e', testScript], {
+      encoding: 'utf8',
+    });
+
+    const expectedDir = path.join(tmpHome, '.config', 'opencode');
+    assert.strictEqual(
+      result.trim(),
+      expectedDir,
+      [
+        'detectConfigDir should fall back to .config/opencode when .claude does not exist.',
+        `Expected: ${expectedDir}`,
+        `Got: ${result.trim()}`,
+      ].join('\n')
+    );
+  });
+});