Phx Deps Update Skill for Claude

Dependency Update (Freshness)

Inventory → update → fix breaks → grouped PRs. This is the only MUTATING

deps skill: it edits mix.exs, mix.lock, and source. Security scanning

stays in /phx-deps-audit; the vet ledger stays in /phx-deps-vet.

Usage

/phx-deps-update                       # inventory + interactive scope pick
/phx-deps-update --scope patch         # bundle all patch bumps, one PR
/phx-deps-update --pkg phoenix_live_view   # one package (+ coupled group)
/phx-deps-update --dry-run             # inventory only, no changes

Iron Laws

• NEVER cross a major version without an explicit mix.exs edit —

mix deps.update stays within requirements. Edit the constraint first;

add override: true only when mix hex.outdated <pkg> shows a

transitive consumer blocking. One major per PR

• ALWAYS snapshot the changelog delta BEFORE updating — capture

deps/<pkg>/CHANGELOG.md, then delta via mix hex.package diff. Never

update blind

• NEVER claim an update is safe without verification — run

/phx-verify (compile --warnings-as-errors + test). "Compiles" ≠ "works"

• ALWAYS move coupled packages together — Phoenix core, Ecto, Ash,

Oban, telemetry families update in the SAME step/commit (see

references/coupled-groups.md)

• NEVER commit a partial bump — mix.lock + mix.exs edits + (for

Phoenix-family) assets/package-lock.json in ONE commit

• HAND OFF security to /phx-deps-audit — run it on the lock diff

before any PR; don't reimplement audit rules

• hex.outdated exit 1 is normal — it means "deps are outdated", not

failure. Capture with || true

Workflow

Phase 0: Discover

Read mix.exs: deps list, umbrella (apps_path:), git/path deps, private

orgs (organization:/repo: in tuples), Phoenix/Ash presence. Create

scratch dir .claude/deps-update/{YYYY-MM-DD}/.

Phase 1: Inventory

mix hex.outdated --all || true — parse the text table (no JSON exists;

see references/update-mechanics.md). Classify each

row patch/minor/major by semver delta; Update not possible = blocked

major (mix.exs constraint). Write inventory.md to scratch. Render

grouped table: Patch / Minor / Major / Blocked / Git-deps (manual).

--dry-run stops here.

Phase 2: Scope (AskUserQuestion)

Present groups with counts and risk. Default recommendation: "Patches (N)

— low risk, bundle into one PR". --scope/--pkg flags skip the prompt.

When ≥2 members of a coupled group are outdated, force them into one step

even under a narrower scope.

Phase 3: Per-Package Update Loop

For each selected package, in coupled-group order:

• Snapshot deps/<pkg>/CHANGELOG.md → scratch/before/
• Update — patch/minor: mix deps.update <pkg> [coupled...];

major: edit mix.exs constraint (+ override: true if needed), then

mix deps.update <pkg>

• git diff mix.lock → the REAL {pkg, old, new} set (hex.outdated says

what could change; the lock diff says what did)

• Changelog delta: mix hex.package diff <pkg> <old>..<new> — keep the

CHANGELOG hunk. Empty → gh api repos/{o}/{r}/releases fallback →

compare-URL note (see references/changelog-sources.md)

• Write scratch/{pkg}-{old}-{new}.md
• Phoenix-family in the diff + assets/package.json exists →

npm install --prefix assets, stage assets/package-lock.json with

the same commit

Phase 4: Verify

Run /phx-verify. On failure → Phase 5; else Phase 6.

Phase 5: Breaking-Change Fixes

Read the changelog deltas for "breaking"/"removed"/"deprecated" + the

compile/test errors. Fix source (apply the sibling-file check). Re-verify.

Phase 6: Security Handoff

Run /phx-deps-audit on the working mix.lock diff (its Mode B default).

BLOCK findings → surface and offer /phx-deps-vet <pkg> <ver> for

accepted risks. Never skip this before a PR.

Phase 7: Group, Commit, PR

Apply the splitting strategy (references/pr-strategy.md):

patches bundled, minors by area, majors solo, coupled groups always

together. PR bodies cite the changelog excerpt, the

https://diff.hex.pm/diff/<pkg>/<old>..<new> link, verification result,

and the deps-audit risk band. Stage lock + mix.exs + package-lock together.

Integration

/phx-deps-update (mutating) → /phx-deps-audit (security, Mode B)
        │                              │ BLOCK → /phx-deps-vet (ledger)
        └→ /phx-verify (gate) → grouped commits / PRs

References

• references/update-mechanics.md — hex.outdated parsing, update vs unlock+get, majors, lock-diff
• references/changelog-sources.md — hex.package diff, gh fallbacks, private orgs
• references/coupled-groups.md — must-move-together groups + edge cases
• references/pr-strategy.md — grouping rules, area buckets, PR template, scratch layout