bug: phase label slugs truncated to empty string for phases 9+

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Summary

When /mgw:project creates issues for a project with many phases, phase labels are generated with malformed slugs starting from a certain phase number. Observed on TJ-Dev-Studio/proto1:

• Issues Implement --headless flag in mgw:run and mgw:issue #127–Write unit tests for lib/state.cjs #133 (phases 7–8) → labels phase:7-foundation-fixes, phase:8-match-experience ✓
• Issues feat: add vision-researcher domain expansion agent to mgw:project #109–feat: wire vision-condenser handoff into gsd:new-project Task spawn #112 (phases 9–10) → labels phase:9-, phase:10- ✗
• Issues feat: replace current_milestone with active_gsd_milestone in project.json #113–Design headless mode contract for mgw CLI #126 (phases 11–15) → labels phase:11-, phase:12-, ... phase:15- ✗

The correct labels (phase:9-daily-and-weekly-engagement, etc.) were created as GitHub labels in a subsequent run, but the issues were never updated.

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Root Cause

File: commands/project.md
Step: create_issues (Pass 1b)
Line 339:

PHASE_SLUG=$(node ~/.claude/get-shit-done/bin/gsd-tools.cjs generate-slug "${PHASE_NAME}" --raw 2>/dev/null | head -c 40 || echo "${PHASE_NAME,,}" | tr ' ' '-' | cut -c1-40)

Mechanism

The bug has two interacting problems:

Problem 1 — Silent empty output when PHASE_NAME is empty:

When PHASE_NAME is empty or unset (see Problem 2 below), gsd-tools generate-slug writes its error to stderr and nothing to stdout, then exits with status 1:

$ node gsd-tools.cjs generate-slug "" --raw 2>/dev/null | head -c 40
(no output)

Because head -c 40 reads zero bytes but exits with status 0, the pipeline exit status is 0. The || fallback never fires. The command substitution captures an empty string, so PHASE_SLUG="".

Problem 2 — PHASE_NAME is unset in later bash calls:

Claude Code executes the multi-step loop in the create_issues step across separate Bash tool invocations. Shell variables (including PHASE_NAME) set in one invocation do not persist to the next. For the phases processed in later invocations (typically starting at the second milestone boundary), PHASE_NAME is not in scope when the PHASE_SLUG generation runs, producing an empty string.

Problem 3 — Fallback uses bash-only syntax (ZSH incompatibility):

Even if the || fallback were to run, the fallback expression echo "${PHASE_NAME,,}" uses bash parameter expansion lowercase operator ${VAR,,}, which is not supported in ZSH. On systems where the default shell is /usr/bin/zsh, this causes bad substitution and silently produces an empty string inside the $() subshell. This means both the primary path and the fallback path can produce empty slugs on ZSH systems.

Why phases 7–8 work but 9+ don't

Phases 7–8 were the first two phases of the first extend milestone. They were processed in the same Bash call where PHASE_NAME was freshly extracted, so the variable was in scope. Phases 9+ belong to the second and subsequent extend milestones — processed in new Bash invocations where PHASE_NAME was not carried over.

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Steps to Reproduce

1. Run /mgw:project on a project that generates 4+ milestones with 9+ total phases.
2. Observe the GitHub labels applied to issues in phases 9 and beyond.
3. Labels will be phase:N- (empty slug) instead of phase:N-<slug>.

Alternatively, simulate the broken PHASE_NAME path in ZSH:

PHASE_NAME=""
PHASE_SLUG=$(node ~/.claude/get-shit-done/bin/gsd-tools.cjs generate-slug "${PHASE_NAME}" --raw 2>/dev/null | head -c 40 || echo "${PHASE_NAME,,}" | tr ' ' '-' | cut -c1-40)
echo "PHASE_SLUG: '${PHASE_SLUG}'"
# Output: PHASE_SLUG: ''

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Proposed Fix

Line 339 — explicit check + ZSH-compatible lowercasing:

PHASE_SLUG=$(node ~/.claude/get-shit-done/bin/gsd-tools.cjs generate-slug "${PHASE_NAME}" --raw 2>/dev/null | head -c 40)
if [ -z "$PHASE_SLUG" ] && [ -n "$PHASE_NAME" ]; then
  PHASE_SLUG=$(echo "$PHASE_NAME" | tr '[:upper:]' '[:lower:]' | tr ' ' '-' | tr -cd 'a-z0-9-' | cut -c1-40)
fi

Key changes:

1. Separates the fallback into an explicit if [ -z ... ] check — avoids relying on || which does not trigger when head exits 0.
2. Replaces ${VAR,,} with tr '[:upper:]' '[:lower:]' — POSIX-compatible, works in both bash and ZSH.
3. Adds tr -cd 'a-z0-9-' to strip any special characters from the slug.
4. The guard [ -n "$PHASE_NAME" ] prevents the fallback from running when PHASE_NAME itself is empty (the upstream issue that should be caught separately with a hard error).

Same fix also needed on line 378 for ISSUE_SLUG:

ISSUE_SLUG=$(node ~/.claude/get-shit-done/bin/gsd-tools.cjs generate-slug "${ISSUE_TITLE}" --raw 2>/dev/null | head -c 40)
if [ -z "$ISSUE_SLUG" ] && [ -n "$ISSUE_TITLE" ]; then
  ISSUE_SLUG=$(echo "$ISSUE_TITLE" | tr '[:upper:]' '[:lower:]' | tr ' ' '-' | tr -cd 'a-z0-9-' | cut -c1-40)
fi

Upstream fix: The PHASE_NAME extraction via python3 and the PHASE_SLUG generation must occur in the same atomic bash invocation. Splitting them across separate Bash tool calls allows the variable to go out of scope.

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Observed Impact

• GitHub labels phase:9- through phase:15- created and applied to 14 issues on TJ-Dev-Studio/proto1
• Correct labels (phase:9-daily-and-weekly-engagement etc.) exist as orphaned labels but are NOT applied to the affected issues
• All affected issues require manual re-labeling

Both commands/project.md (in repo) and ~/.claude/commands/mgw/project.md (installed copy) are identical and both contain the bug.

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Environment

• Shell: /usr/bin/zsh (ZSH 5.x)
• Platform: Arch Linux x86_64
• Claude Code model: claude-sonnet-4-6
• MGW invocation: /mgw:project in extend mode (second extension run)

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MGW . triage-complete . 2026-03-01T19:08:58.495Z

Triage Complete

Scope	small -- 2 lines across 2 files (commands/project.md + installed copy)
Validity	confirmed -- all three failure mechanisms verified against actual code
Security	none
Route	gsd:quick -- targeted two-line patch with fully diagnosed root cause and correct proposed fix
Gates	All passed

Upstream Context (glittercowboy/get-shit-done)

Checked the upstream GSD repo for a related issue or PR. No direct match found for the generate-slug empty-string / head -c exit-code problem. The closest is #733 (OPEN) — gsd-tools.cjs commit silently truncates multi-word commit messages to first word — which follows the same pattern of gsd-tools CLI silently producing wrong output due to incorrect argument parsing, but is a different command and different root cause. No upstream patch to wait on — the fix belongs entirely in MGW's commands/project.md.

Ready for pipeline execution.

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MGW · work-starting · 2026-03-01T19:15:58.937Z

Work Starting

Route	gsd:quick — targeted two-line patch with fully diagnosed root cause and correct proposed fix
Scope	small — 2 files across mgw:project, create_issues step, phase label generation
Conflicts	None

Work begins on branch issue/100-bug-phase-label-slugs-truncated-to-empty.

Affected Files

• commands/project.md
• .claude/commands/mgw/project.md

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MGW · execution-complete · 2026-03-01T19:20:23.295Z

Execution Complete

2 atomic commit(s) on branch issue/100-bug-phase-label-slugs-truncated-to-empty.

Changes: 2 files changed, 16 insertions(+), 4 deletions(-)

Preparing pull request.

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MGW · pr-ready · 2026-03-01T19:21:42.673Z

PR Ready

PR #101 — #101

Fixed empty PHASE_SLUG/ISSUE_SLUG for phases 9+ by replacing broken || head -c 40 fallback and bash-only ${VAR,,} with POSIX if [ -z ] guard and tr '[:upper:]' '[:lower:]'.

Testing procedures posted on the PR.
This issue will auto-close when the PR is merged.

Pipeline Summary

Stage	Status
Triage	✓
Planning	✓
Execution	✓
PR Creation	✓