SDLC

From an approved ticket to a squash merge.

The flow

+--------------------------+
| ticket                   |   labelled `model:*`, assigned to `@me`:
+--------------------------+   the approved ticket is the plan
             |
             v
+--------------------------+
| branch                   |   one ticket, one branch, one PR
+--------------------------+
             |
             v
+--------------------------+
| red slice test           |   enters where a real consumer enters; fails first
+--------------------------+
             |
             v
+--------------------------+
| implement the slice      |   smallest change that satisfies the ticket
+--------------------------+
             |
             v
+--------------------------+
| mutation gate            |   pre-commit or Stop hook; a survivor blocks
+--------------------------+
             |
             v
+--------------------------+
| PR, `Closes #N`          |   CI green
+--------------------------+
             |
             v
+--------------------------+
| review, squash merge     |   branch deleted on merge
+--------------------------+

The rules behind it

Rule	What it means in practice
Intent lives in the tracker	Design notes go in the ticket; a new .md file in the tree is blocked
An approved ticket is the plan	The model:* label is the approval; the assignee names who works it
One ticket, one branch, one PR	Branch 42-slug, PR body Closes #42
Every ticket names an assignee	Triage sets it alongside the model:* label
No ticket, no change past ~40 lines	diff-discipline blocks the commit
Red slice test first	Watched failing for the right reason before any code
The gate runs before the commit lands	A survivor blocks
Squash-only merges	The branch is deleted on merge

A ticket, end to end

gh issue create -t "is_adult accepts 17" -b "Expected: 18 is the first adult age."
# triage: create missing labels, then add the label (approval) and assignee
sh <agent-sdlc checkout>/bin/sdlc-bootstrap
gh issue edit 42 --add-label model:sonnet --add-assignee @me

/kata 42

• The worker branches 42-is-adult-boundary off origin/main.
• It writes test_eighteen_is_the_first_adult_age, watches it fail, then fixes the code.
• The commit runs the gate; a survivor sends it back to the test.
• It opens the PR assigned to @me with Closes #42 and waits for CI.
• You read it and type LGTM; it squash-merges, hands any root-owned files back with a chown, and removes the worktree.

Vertical slice

• A slice test enters through something a real consumer calls: an exported header, a CLI subcommand, a published API.
• It proves the feature works end to end, like a walking skeleton before its internals are filled in.
• Unit tests then cover what the slice can't reach: numeric edge cases, error paths, boundary values.

Source: rules/tickets.md, rules/testing.md, rules/diff-discipline.md.