fix(server): keep env-provided OPENCODE_BINARY when settings clear the override

CHANGELOG.md

@@ -30,6 +30,7 @@ All notable changes to this project will be documented in this file.
 - Desktop: browser pages served from a self-signed loopback HTTPS address now load instead of being blocked by the certificate warning.
 - Browser: typing a comment on a page no longer triggers app shortcuts.
 - Skills Catalog: the source is now named ClawHub instead of "ClawdHub" (thanks to @makeittech).
+- Settings: an explicitly set `OPENCODE_BINARY` environment variable is no longer discarded when settings contain an empty opencodeBinary value; the environment variable keeps pointing the managed OpenCode server at the binary you chose.
 
 ## [1.18.4] - 2026-08-14
 

packages/web/server/lib/opencode/env-runtime.js

@@ -1011,7 +1011,13 @@ export const createOpenCodeEnvRuntime = (deps) => {
       const normalized = normalizeOpencodeBinarySetting(settings.opencodeBinary);
 
       if (normalized === '') {
-        delete process.env.OPENCODE_BINARY;
+        // The empty-string sentinel drops a previously APPLIED settings
+        // override (source === 'settings'). An OPENCODE_BINARY provided by
+        // the user's own environment is explicit configuration and must not
+        // be destroyed by an empty setting.
+        if (state.resolvedOpencodeBinarySource === 'settings') {
+          delete process.env.OPENCODE_BINARY;
+        }
         state.resolvedOpencodeBinary = null;
         state.resolvedOpencodeBinarySource = null;
         clearWslOpencodeResolution();

packages/web/server/lib/opencode/env-runtime.test.js

@@ -200,6 +200,39 @@ describe('OpenCode env runtime', () => {
     expect(state.resolvedOpencodeBinarySource).toBe('settings');
   });
 
+  it('keeps an env-provided OPENCODE_BINARY when the setting is an empty-string sentinel', async () => {
+    const dir = createTempDir('openchamber-env-opencode-');
+    const binary = path.join(dir, 'opencode');
+    fs.writeFileSync(binary, '#!/bin/sh\nexit 0\n');
+    if (process.platform !== 'win32') fs.chmodSync(binary, 0o755);
+    process.env.OPENCODE_BINARY = binary;
+    const { runtime, state } = createRuntime({ opencodeBinary: '' });
+
+    await expect(runtime.applyOpencodeBinaryFromSettings()).resolves.toBeNull();
+    expect(process.env.OPENCODE_BINARY).toBe(binary);
+    expect(state.resolvedOpencodeBinary).toBeNull();
+    expect(state.resolvedOpencodeBinarySource).toBeNull();
+  });
+
+  it('drops a previously applied settings override when the setting is cleared to an empty string', async () => {
+    const dir = createTempDir('openchamber-settings-opencode-');
+    const binary = path.join(dir, 'opencode');
+    fs.writeFileSync(binary, '#!/bin/sh\nexit 0\n');
+    if (process.platform !== 'win32') fs.chmodSync(binary, 0o755);
+    const settings = { opencodeBinary: binary };
+    const { runtime, state } = createRuntime(settings);
+
+    await expect(runtime.applyOpencodeBinaryFromSettings()).resolves.toBe(binary);
+    expect(process.env.OPENCODE_BINARY).toBe(binary);
+    expect(state.resolvedOpencodeBinarySource).toBe('settings');
+
+    settings.opencodeBinary = '';
+    await expect(runtime.applyOpencodeBinaryFromSettings()).resolves.toBeNull();
+    expect(process.env.OPENCODE_BINARY).toBeUndefined();
+    expect(state.resolvedOpencodeBinary).toBeNull();
+    expect(state.resolvedOpencodeBinarySource).toBeNull();
+  });
+
   it('prefers the bundled CLI over a user-installed OpenCode from PATH', () => {
     const bundledDir = createTempDir('openchamber-bundled-opencode-');
     const bundledBinary = path.join(bundledDir, process.platform === 'win32' ? 'opencode.exe' : 'opencode');