Execute

Update Check (run first)

_UPD=$(~/.claude/skills/upstack/bin/upstack-update-check 2>/dev/null || .claude/skills/upstack/bin/upstack-update-check 2>/dev/null || true)
[ -n "$_UPD" ] && echo "$_UPD" || true

If output shows UPGRADE_AVAILABLE : read ~/.claude/skills/upstack/skills/upgrade/SKILL.md and follow the "Inline upgrade flow" (auto-upgrade if configured, otherwise AskUserQuestion with 4 options, write snooze state if declined). If JUST_UPGRADED : tell user "Running upstack v{to} (just updated!)" and continue.

Execute

You are implementing a plan using strict Red/Green TDD. Ask as few questions as possible and keep churning.

Pre-flight

• If no plan exists in context: warn the user and suggest running /plan first. Skipping planning may cause sloppy code.
• If on main/master: create a feature branch with a descriptive name.
• If a test rig was opted into during /plan: confirm it's set up and working before proceeding.

Ticket Mode

If the user passes --ticket (e.g., /execute --ticket P1-3):

1. Find the structured ticket block in the plan's Phase 5 YAML output.
2. Extract: title, files, acceptance_criteria, depends_on, context, and effort.
3. If ticket ID is not found: error with a list of available ticket IDs from the plan.
4. Announce: "Executing ticket P1-3: "

Dependency Check (ticket mode only)

Before writing any code, check if dependent tickets are complete:

1. Read TODOS.md. For each ID in depends_on, check if it's marked [x].
2. If Linear CLI is available (which linear 2>/dev/null), also check Linear ticket status.
3. If any dependency is incomplete: AskUserQuestion warning — "Ticket P1-3 depends on P1-1 and P1-2 which aren't done yet. Proceed anyway?"
4. If TODOS.md doesn't exist: warn and proceed (dependencies can't be verified).

Phase 1: Familiarize (before writing anything)

Determine if this plan has UI impact: Check if any planned file changes are in a UI/frontend package (e.g., packages/ui/, src/app/, src/components/, or any directory containing .tsx/.jsx files).

If UI impact exists (even if the primary feature is backend):

• Start the dev server if not running.
• Use agent-browser open to navigate affected pages.
• Click through paths in the plan that currently work.
• Capture current state before making changes.
• Note actual selectors and @refs for writing E2E tests.

For backend paths (always, regardless of UI impact):

• Use curl to hit relevant API endpoints.
• Observe current request/response patterns.
• Note auth requirements, headers, response shapes.

Phase 2: RED — Write all tests first

• Write tests for every feature/fix described in the plan.
• Ticket mode: scope tests to the ticket's acceptance_criteria only. Do not write tests for other tickets.
• Cover the happy path, edge cases, and error cases.
• Run the test suite. Confirm all new tests FAIL.
• If any new test passes already: investigate. Is the feature already implemented? Adjust the plan accordingly.

Phase 3: GREEN — Implement

• Write the minimum code to make each test pass.
• One atomic commit per logical change.
• Commit format: ():
• Types: feat, fix, refactor, test, docs, chore

Phase 4: Confirm GREEN

• Run the full test suite. Every test must pass.
• If any test fails: fix and re-run. Do not move on until green.

Scope Guard

If the task grows beyond what was planned:

1. STOP immediately.
2. Add out-of-scope items to TODOS.md.
3. AskUserQuestion: "Discovered [X] is also needed. Include in current scope, note as follow-up, or re-plan?"
4. Only AskUserQuestion for scope changes. For implementation details, make the simpler choice and keep moving.

File Scope Guard (ticket mode only)

When in ticket mode, the ticket's files list defines the expected scope:

• Before modifying a file not in the files list: AskUserQuestion — "File path/to/file.ts isn't in this ticket's scope. Add to scope or create a follow-up ticket?"
• This prevents parallel agents from creating merge conflicts by touching the same files.

Phase 5: Post-Execution (ticket mode only)

After all tests pass, update tracking systems:

1. Update TODOS.md: Mark the ticket as done — change - [ ] to - [x] for the ticket's line.
2. Update Linear (if CLI available): Run linear issue update --status "Done".
3. Report unblocked tickets: Read the plan's dependency DAG. List any tickets whose depends_on are now all complete. Announce: "Newly unblocked: P1-4, P2-3"

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Upsolve-Labs
• Source: Upsolve-Labs/upstack
• License: MIT
• Homepage: https://upsolve.ai/

Install and usage instructions live in the source repository linked above.