Session Triage: Pack Install Failures

Target and Evidence

User-identified issue: What happened during the failed pack installs above?

Evidence sources:

Active conversation tool output from `$pack install upgrade-alignment-pages` and `$pack install session-triage`.
.codex/skills/session-triage/SKILL.md and .codex/skills/session-triage/ALIGNMENT-PAGE.md.
/Users/georgele/.codex/skills/pack/scripts/pack.sh, the global pack launcher.
/Users/georgele/projects/tools/agentic-skills/scripts/pack.sh, the repository-level pack manager.
Local reproduction commands comparing /bin/bash 3.2 and /opt/homebrew/bin/bash 5.3.
CLAUDE.md project workflow instructions and current repo state.

Verification Verdict

Verdict: verified.

The first failure is verified as a shell compatibility bug. The launcher delegates with plain exec bash; this system resolves bash to /bin/bash 3.2; and Bash 3.2 treats iteration over an empty array under set -u as an unbound variable. The pack manager hits that exact shape when installing an individual skill because install_packs remains empty while install_skills is populated.

The second failure is verified as a sandbox/write-permission issue around creating .agents/.pack.lock. The Bash 5 command timed out waiting for a lock with unknown metadata, and a direct default-sandbox mkdir .agents/.pack.lock failed with Operation not permitted. Escalating the same repo-level Bash 5 install path allowed the writes and the skill installed successfully.

Timeline

User requested $pack install upgrade-alignment-pages.
I used the pack skill and ran the bundled launcher at /Users/georgele/.codex/skills/pack/scripts/pack.sh install upgrade-alignment-pages.
The launcher delegated to the repo script with plain bash and failed: line 795: install_packs[@]: unbound variable.
I confirmed the skill exists: upgrade-alignment-pages is provided by pack alignment-page-admin.
I diagnosed macOS Bash 3.2 empty-array behavior and tried running the launcher with Homebrew Bash 5.
That still failed through the wrapper because the wrapper itself does exec bash "$REPO_ROOT/$DELEGATE_SCRIPT" "$@", reselecting /bin/bash.
I tried running the repository-level script with Bash 5 in the default sandbox. It timed out waiting for .agents/.pack.lock.
A direct mkdir .agents/.pack.lock in the default sandbox failed with Operation not permitted.
I reran the repository-level script with Homebrew Bash 5 and escalation; the install succeeded.
For session-triage, I skipped the known bad launcher path and used the already-verified repo-level Bash 5 escalated path; it installed successfully.

Root Cause

Primary Cause: Pack Implementation Compatibility

The pack manager is not robust against macOS default Bash 3.2 for individual skill installs. The script sets set -euo pipefail, initializes arrays, and then iterates an empty array without a length guard. Bash 5 accepts that. Bash 3.2 fails with an unbound-variable error.

Secondary Cause: Launcher Re-selects Default Bash

The global pack launcher ignores the shell used to invoke it and executes the repo script with plain bash. On this machine, bash resolves to /bin/bash, so running the wrapper through Homebrew Bash did not preserve the workaround.

Operational Cause: Sandbox Write Restriction

The pack manager writes .agents/project.json and creates .agents/.pack.lock. In this session's default sandbox, direct creation of the hidden lock directory was denied. Escalation was required for the pack manager writes even though the workspace itself is otherwise writable.

Responsible contract gap: the pack implementation and launcher. The pack skill's user-facing workflow was adequate enough to route the command, but the underlying launcher/script combination is not portable on macOS default Bash and does not fail with a clear modern-Bash requirement. There was also an environment-specific Codex sandbox write requirement.

Evidence Matrix

Claim	Evidence	Inference	Confidence	Decision Impact
The first failure was an empty-array nounset failure.	Active tool output: `scripts/pack.sh: line 795: install_packs[@]: unbound variable`. Repo script initializes `install_packs=()` and later loops `for pack in "${install_packs[@]}"`.	Installing an individual skill leaves `install_packs` empty, so Bash 3.2 fails before reaching `install_single_skill`.	High	Patch the repo script or enforce a modern Bash runtime.
The wrapper made the Bash 5 workaround ineffective.	`/Users/georgele/.codex/skills/pack/scripts/pack.sh` ends with `exec bash "$REPO_ROOT/$DELEGATE_SCRIPT" "$@"`. `command -v bash` returned `/bin/bash`.	Even if the wrapper is launched by Bash 5, it delegates through the PATH's default Bash.	High	Patch both Codex and Claude global pack launchers or make the repo script Bash 3.2-safe.
macOS Bash 3.2 reproduces the empty-array issue; Bash 5 does not.	`/bin/bash -c 'set -u; a=(); for x in "${a[@]}"; do :; done'` failed with `a[@]: unbound variable`. The same command under `/opt/homebrew/bin/bash` printed `ok`.	The failure is not specific to the skill name; it is shell-version behavior.	High	Validation should include macOS `/bin/bash`, not only Homebrew Bash.
The lock timeout came from sandbox write denial.	The Bash 5 repo script in the default sandbox timed out waiting for `.agents/.pack.lock` with unknown metadata. Direct `mkdir .agents/.pack.lock` failed with `Operation not permitted`.	The lock was not owned by another process; it could not be created in the default sandbox.	High	Codex should request escalation for pack installs when the lock write fails.
The final install path was correct.	Escalated `/opt/homebrew/bin/bash /Users/georgele/projects/tools/agentic-skills/scripts/pack.sh install ...` installed local roots and updated `.agents/project.json`.	Both failure modes were bypassed: Bash 5 avoided the array issue and escalation allowed project writes.	High	This is a valid workaround, but it should not be the permanent user-facing path.

Confidence and Assumptions

Conclusion	Status	What Could Change It
The empty-array behavior caused the unbound-variable failure.	Evidence-backed	A trace showing a different expression at line 795 under the same script version.
The wrapper should not delegate with plain `bash` unless the repo script supports Bash 3.2.	Evidence-backed	A repository policy explicitly requiring Bash 5 and enforcing it before delegation.
The sandbox lock failure was environmental, not a stale live lock.	Evidence-backed	A hidden process or filesystem event log showing another actor repeatedly creating/removing the lock.
No broad recurrence analysis is needed.	Provisional	Multiple other sessions showing the same install path failing for different reasons.

Alternatives Considered

Missing skill: rejected. pack.sh which upgrade-alignment-pages found the skill in alignment-page-admin.
Stale pack lock: rejected for this incident. Lock metadata was unknown and direct creation was denied by the sandbox.
User instruction conflict: not supported. The pack workflow was followed; the failure occurred inside the launcher/script.
Git repository problem: unrelated to the install failure. It only prevented committing/pushing the resulting project config.

Source Coverage Gaps

I did not inspect all historical sessions or run a full test suite for the agentic-skills repository. That is not necessary for this narrow incident, but it would be useful before changing the global pack manager.

Recommended Fix

Smallest durable fix: make the repository pack script safe under macOS /bin/bash 3.2 and add a targeted regression test for individual skill installs under that shell.

Patch candidates:

/Users/georgele/projects/tools/agentic-skills/scripts/pack.sh: guard empty-array loops before iterating install_packs, install_skills, remove_packs, and remove_skills.
/Users/georgele/projects/tools/agentic-skills/global/codex/pack/scripts/pack.sh and /Users/georgele/projects/tools/agentic-skills/global/claude/pack/scripts/pack.sh: either preserve a verified modern Bash runtime or fail clearly if the delegated repo script requires Bash newer than the resolved bash. If the repo script is made Bash 3.2-safe, the wrapper change is less urgent but still worth clarifying.

Suggested wording for the pack implementation note:

Pack install/remove must pass on macOS /bin/bash 3.2 with set -u. Guard all empty-array iterations, or explicitly select/fail on a supported Bash version before delegating to scripts/pack.sh.

Operational rule for Codex runs:

If pack install/refresh/remove fails to create .agents/.pack.lock with Operation not permitted or times out with unknown pid/started_at/command, rerun the same pack command with escalation instead of retrying the non-escalated path.

Validation Plan

After patching, run an individual-skill install from a temporary project with macOS Bash 3.2: /bin/bash /Users/georgele/projects/tools/agentic-skills/scripts/pack.sh install upgrade-alignment-pages.
Run the same scenario through the global Codex launcher: /Users/georgele/.codex/skills/pack/scripts/pack.sh install upgrade-alignment-pages.
Run a pack install and a remove path to cover both populated and empty array combinations.
Run cmp -s global/codex/pack/scripts/pack.sh global/claude/pack/scripts/pack.sh to confirm mirrored launcher behavior when both surfaces should match.
Run rg -n 'for .*"\$\{.*\[@\]\}"' scripts/pack.sh and inspect any remaining unguarded array loops under set -u.
Verify project state with scripts/pack.sh status and scripts/pack.sh which upgrade-alignment-pages.

Review Gates

Evidence Coverage Gate

Is the evidence sufficient to accept the diagnosis that the install failures were caused by Bash 3.2 empty-array behavior plus sandbox lock-write denial?

Accept evidence as sufficient Needs more command trace Other / None of the above Need clarification

Proposed Fix Gate

Which repair direction should be treated as the approved next implementation target?

Make repo script Bash 3.2-safe Enforce modern Bash in launchers Do both fixes Other / None of the above Need clarification

Artifact Destination Gate

Should implementation, if requested, happen in the agentic-skills repository rather than this non-Git AFPS tracker directory?

Patch agentic-skills repo Analysis only for now Other / None of the above Need clarification