Issue 15541 runtime reproduction
Main: 89fe509232e787b51d0cf695861afe73316ce85b
Linux, Node v24.21.0; git git version 2.43.0
Fixture: 122629 tracked ~1KB files, source ext4. Seven simultaneous orchestration.launchThread RPC requests with worktree strategy, base main, startFromOrigin false, distinct branches. No provider turns started.
Attempt 1: worktrees ext4; six RPC createWorktree failures: Git output exceeded 1000000 bytes; free inodes exhausted; seventh interrupted. Not the reported timeout.
Attempt 2: worktrees tmpfs; seven thread launch receipts accepted; all seven preparation jobs later fail Git command timed out. Severe VM contention; spans show ~1628 seconds total, not a measured exact 300-second exit.
After attempt 2: git worktree list contains only source; all seven triage-tmpfs branches remain.
Retry: same first thread and workspace branch, new command ID, reuseExistingThread=true; fails branch_already_exists.
Reporter NTFS and complete clean orphan worktrees were NOT verified.

[01:33:32.409] WARN (#8794) http.span=1628175ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-launch-1',
    threadId: 'thread:project:triage-15541-project:b5aa8254-5912-425e-8c06-68244b0d0e38',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-launch-1',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:b5aa8254-5912-425e-8c06-68244b0d0e38',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        detail: 'Git command timed out.'
      }
    }
  }
[01:33:32.412] WARN (#8886) http.span=1628178ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-launch-5',
    threadId: 'thread:project:triage-15541-project:5050c41b-4de2-41ba-a5af-208fb0652ea4',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-launch-5',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:5050c41b-4de2-41ba-a5af-208fb0652ea4',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        detail: 'Git command timed out.'
      }
    }
  }
[01:33:32.414] WARN (#8914) http.span=1628180ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-launch-6',
    threadId: 'thread:project:triage-15541-project:22856ad1-6688-4d54-80b7-2143c9728a2a',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-launch-6',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:22856ad1-6688-4d54-80b7-2143c9728a2a',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        detail: 'Git command timed out.'
      }
    }
  }
[01:33:32.423] WARN (#8829) http.span=1628189ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-launch-3',
    threadId: 'thread:project:triage-15541-project:cfedc0fa-aaac-40db-bc52-bcda627774c4',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-launch-3',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:cfedc0fa-aaac-40db-bc52-bcda627774c4',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        detail: 'Git command timed out.'
      }
    }
  }
[01:33:32.426] WARN (#8811) http.span=1628192ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-launch-2',
    threadId: 'thread:project:triage-15541-project:55c1eda7-0cd1-4439-9cea-e244295bf588',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-launch-2',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:55c1eda7-0cd1-4439-9cea-e244295bf588',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        detail: 'Git command timed out.'
      }
    }
  }
[01:33:32.436] WARN (#8778) http.span=1628202ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-launch-0',
    threadId: 'thread:project:triage-15541-project:8370c0cd-ca12-4ecc-bbaa-8d924c928920',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-launch-0',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:8370c0cd-ca12-4ecc-bbaa-8d924c928920',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        detail: 'Git command timed out.'
      }
    }
  }
[01:33:32.437] WARN (#8857) http.span=1628203ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-launch-4',
    threadId: 'thread:project:triage-15541-project:96407023-9b9a-4568-af2c-8f82157443b0',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-launch-4',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:96407023-9b9a-4568-af2c-8f82157443b0',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        detail: 'Git command timed out.'
      }
    }
  }
[01:34:42.774] WARN (#10328) http.span=1698540ms: Thread workspace preparation failed
  {
    commandId: 'triage-15541-retry',
    threadId: 'thread:project:triage-15541-project:8370c0cd-ca12-4ecc-bbaa-8d924c928920',
    cause: {
      _tag: 'ThreadLaunchError',
      operation: 'provision-worktree',
      commandId: 'triage-15541-retry',
      projectId: 'triage-15541-project',
      threadId: 'thread:project:triage-15541-project:8370c0cd-ca12-4ecc-bbaa-8d924c928920',
      cause: {
        _tag: 'GitCommandError',
        operation: 'GitVcsDriver.createWorktree',
        command: 'git',
        cwd: '/tmp/t3-15541-large-repo',
        argumentCount: 9,
        exitCode: 255,
        stdoutLength: 0,
        stderrLength: 103,
        reason: 'branch_already_exists',