Create Milestone

Step 2: Duplicate Check

Call backlog_list_milestones(state="open") and scan the returned list for any entry where title matches the requested title (case-insensitive).

If an open milestone with the same title already exists, report it and ask: "Use existing or create new?" via AskUserQuestion.

If user chooses existing: print its number and stop.

Step 2.5: Wave Ordering (when items are known)

When a milestone is being created alongside a set of known backlog items (not just a blank milestone), plan the execution order before creating the milestone. Use mcp__sequential_thinking__sequentialthinking to structure the analysis.

flowchart TD
    Start(["Items known for this milestone?"]) --> Q{"Items provided<br>or identified?"}
    Q -->|"No — blank milestone"| Skip["Skip to Step 3"]
    Q -->|"Yes — items listed"| Dep["Dependency Mapping"]
    Dep --> Classify["Classify into waves"]
    Classify --> Restart["Identify restart points"]
    Restart --> Record["Record wave plan in description"]
    Record --> Step3["Proceed to Step 3"]

Dependency Mapping — for each item, answer:

1. What does this item need to exist before it can be built?
2. What does this item enable once it exists?

Classify into waves — group items by dependency tier:

• Wave 0: Items with no dependencies on other milestone items (foundation)
• Wave N+1: Items whose dependencies are all satisfied by Waves 0–N
• Items within the same wave must be independent (no shared file writes, no mutual dependencies) — they run in parallel

Identify restart points — a restart is needed between waves when:

• A wave produces tooling that subsequent waves should use (e.g., verification infrastructure, discovery store, feedback routing)
• Skipping the restart means the next wave doesn't benefit from the previous wave's output
• Not every wave boundary needs a restart — only where new capabilities must be active

Record in description — append the wave plan to the milestone description so /group-items-to-milestone and /groom-milestone can reference it:

Wave 0 (Foundation): #N1, #N2
  🔄 RESTART — [what becomes active]
Wave 1 (Category): #N3, #N4, #N5
  🔄 RESTART — [what becomes active]
Wave 2 (Category): #N6, #N7
...

Step 3: Create Milestone

Use the Python script (preferred — returns structured output):

uv run .claude/skills/gh/scripts/github_project_setup.py milestone create \
  --title "{title}" \
  --description "{description}" \
  --due "{YYYY-MM-DD}"

Omit --due if not provided. Omit --description if not provided.

Capture the milestone number from the output line Created milestone #{number}: ….

Step 4: Confirm

Milestone created.

  Title:   {title}
  Number:  #{number}
  Due:     {due date or "not set"}
  URL:     {html_url from script output}

Next steps:
  Assign items:  /group-items-to-milestone {number}
  Start work:    /start-milestone {number}

Error Handling

• GITHUB_TOKEN missing: report and stop.
• Duplicate found and user picks existing: print existing milestone number and next-step commands, stop.
• API error: print full response and stop.