diff --git a/packages/cli/src/context/core/git-env.ts b/packages/cli/src/context/core/git-env.ts
index 645a29cc..0bb7bf74 100644
--- a/packages/cli/src/context/core/git-env.ts
+++ b/packages/cli/src/context/core/git-env.ts
@@ -31,6 +31,10 @@ function sanitizedGitEnv(env: NodeJS.ProcessEnv = process.env): NodeJS.ProcessEn
  * directory is an existing repo ktx did not create and the machine has no configured git
  * identity (e.g. a fresh Mac with no ~/.gitconfig), without mutating the user's repo config.
  * Explicit `--author` flags on individual commits still take precedence over GIT_AUTHOR_NAME.
+ *
+ * `commit.gpgsign=false` is injected as a per-invocation `-c` override so ktx's commits never
+ * attempt GPG signing: ktx commits under a synthetic identity that can never own a secret key, so
+ * a user's `commit.gpgsign=true` would otherwise fail every commit with "No secret key".
  */
 export function createSimpleGit(baseDir: string, identity?: { name: string; email: string }): SimpleGit {
   const env = sanitizedGitEnv();
@@ -40,5 +44,5 @@ export function createSimpleGit(baseDir: string, identity?: { name: string; emai
     env.GIT_COMMITTER_NAME = identity.name;
     env.GIT_COMMITTER_EMAIL = identity.email;
   }
-  return simpleGit({ baseDir, unsafe: { allowUnsafeAskPass: true } }).env(env);
+  return simpleGit({ baseDir, config: ['commit.gpgsign=false'], unsafe: { allowUnsafeAskPass: true } }).env(env);
 }
diff --git a/packages/cli/test/context/core/git.service.init-identity.test.ts b/packages/cli/test/context/core/git.service.init-identity.test.ts
index b84b9aba..a1fb2aac 100644
--- a/packages/cli/test/context/core/git.service.init-identity.test.ts
+++ b/packages/cli/test/context/core/git.service.init-identity.test.ts
@@ -94,4 +94,23 @@ describe('GitService.initialize without a configured git identity', () => {
     }).trim();
     expect(localName).toBe('');
   });
+
+  // Regression for KLO-735: a machine with commit.gpgsign=true makes git try to GPG-sign every
+  // commit, but ktx commits under a synthetic identity that can never own a secret key, so signing
+  // fails with "No secret key". ktx commits must succeed regardless of the user's signing config.
+  it('commits even when the global git config forces gpg signing', async () => {
+    // Force signing and point gpg at a program that always fails, mirroring a machine whose
+    // configured signing key does not match ktx's synthetic identity.
+    await writeFile(
+      join(homeDir, '.gitconfig'),
+      '[user]\n\tuseConfigOnly = true\n[commit]\n\tgpgsign = true\n[gpg]\n\tprogram = false\n',
+      'utf-8',
+    );
+
+    const service = new GitService(coreConfig(repoDir));
+    await expect(service.onModuleInit()).resolves.toBeUndefined();
+
+    const head = await service.revParseHead();
+    expect(head).toMatch(/^[0-9a-f]{40}$/);
+  });
 });
diff --git a/packages/cli/test/context/core/git.service.repo-isolation.test.ts b/packages/cli/test/context/core/git.service.repo-isolation.test.ts
index 569750c8..07478019 100644
--- a/packages/cli/test/context/core/git.service.repo-isolation.test.ts
+++ b/packages/cli/test/context/core/git.service.repo-isolation.test.ts
@@ -21,7 +21,11 @@ function coreConfig(configDir: string): KtxCoreConfig {
 }
 
 function git(cwd: string, args: string[]): string {
-  return execFileSync('git', args, {
+  // `-c commit.gpgsign=false` keeps fixture commits deterministic regardless of the host's git
+  // config: a contributor with commit.gpgsign=true would otherwise fail these raw commits under a
+  // synthetic identity that owns no secret key.
+  const fixtureArgs = args[0] === 'commit' ? ['-c', 'commit.gpgsign=false', ...args] : args;
+  return execFileSync('git', fixtureArgs, {
     cwd,
     encoding: 'utf-8',
     env: {