diff --git a/DECISIONS.md b/DECISIONS.md
index cf64305..04df421 100644
--- a/DECISIONS.md
+++ b/DECISIONS.md
@@ -217,3 +217,27 @@ Architecture decisions and dead-ends. One line of rationale each. (§0, §8)
   W5/C4-C5 PASSes — keep it RUNNING; defer its C6 teardown until the operator explicitly says
   otherwise. This overrides the plan §5/§6 "destroy the throwaway" for that one VM only. All other
   cleanup proceeds normally (the Builder's first throwaway was already destroyed; RAM accounting holds).
+
+## Phase 1b — lint/format tooling (open decisions §6, settled W0)
+- **Formatters/linters (RL1):** Nix = `nixpkgs-fmt` (format) + `statix` (lints) + `deadnix` (dead
+  code); Python = `ruff` (lint + format); Shell = `shellcheck` + `shfmt -i 2 -ci`; YAML = `yamllint`.
+  Kept `nixpkgs-fmt` over `alejandra` because it was already the repo `formatter` and devshell tool
+  (no extra churn / restyle of every .nix). All built from the already-pinned nixpkgs via a flake
+  `lint` devshell (`nix develop .#lint`) so CI and local use byte-identical tool versions.
+- **Lint entrypoint:** `scripts/lint.sh` (check-only by default; `--fix` auto-applies). The
+  `.drone.yml` push pipeline runs it via `nix develop .#lint --command bash scripts/lint.sh`.
+- **ruff strictness:** `select = [E,F,W,I,UP,B,C4,SIM]`, `ignore = [E501]` (line length is the
+  formatter's job; only un-splittable strings would trip it). `line-length=100`, `target=py311`.
+- **Drone lint stage = FAIL (not warn).** The codebase is green now, so enforce from here on — an
+  unclean commit fails the `lint` step. (Resolves the §6 open question.)
+- **Python type-checking (mypy/pyright): DEFERRED to IDEAS**, not added in 1b. The harness is small
+  and dynamically typed around `abra`/subprocess JSON; gradual typing is a larger effort than this
+  bounded pass warrants. Revisit if Phase 2's 18-recipe ramp shows type bugs.
+- **blocking vs advisory split (§3):** treated as in the phase plan — tests-real, Nix-idempotent,
+  no-footguns, no-secrets, log-redaction, harness-DRY = blocking; readability/docs/arch-drift =
+  advisory unless a real plan deviation. Recorded per-finding in REVIEW-1b / BACKLOG-1b.
+- **cc-ci self-CI push trigger:** the lint stage lives in the `event: push` pipeline. The Gitea→Drone
+  push webhook on this instance is flaky (`last_status: None`; documented §4.1) and predates 1b —
+  recipe CI uses polling as primary, but cc-ci's *own* self-test/lint relies on the push webhook.
+  The lint stage is correctly wired and proven green via the identical `nix develop .#lint` command;
+  reliably auto-firing it on every push is tracked as a (pre-existing) infra item, not a 1b lint gap.
diff --git a/JOURNAL-1b.md b/JOURNAL-1b.md
index d644852..641c99b 100644
--- a/JOURNAL-1b.md
+++ b/JOURNAL-1b.md
@@ -22,3 +22,44 @@ Lint-target inventory: 14 `.nix`, 32 `.py`, 1 `.sh` (`scripts/bootstrap-drone-oa
 
 Next: W0 — add the `lint` devshell + entrypoint + tool configs to the flake; auto-format; fix
 findings; wire the `.drone.yml` lint stage.
+
+## 2026-05-27 — W0 built: lint toolchain + format + drone stage
+
+Added (commits 2cede01 format/fixes, 4af427c drone stage, + tooling commits):
+- `flake.nix`: `lint` devshell (`nix develop .#lint`) = nixpkgs-fmt, statix, deadnix, ruff,
+  shellcheck, shfmt, yamllint, built from the already-pinned nixpkgs (no registry/network surprise —
+  `nix build <pin>#ruff` resolves from cache.nixos.org). Default devshell also gets them.
+- `scripts/lint.sh` (check / `--fix`), `ruff.toml`, `.yamllint.yaml`.
+- `.drone.yml`: a `lint` step in the `event: push` pipeline running
+  `nix develop .#lint --command bash scripts/lint.sh` (FAILs the build on any unclean file).
+
+Format/lint cleanup (semantics-preserving): ruff format on all 32 .py; nixpkgs-fmt drone-runner.nix;
+shfmt scripts; ruff SIM105/SIM115 (contextlib.suppress / `with open`); statix (merge sops
+`secrets.*`, empty-pattern → `_`); deadnix (drop unused `self`/`lib`/overlay `final`).
+
+Verification (on cc-ci, clean tar'd checkout /tmp/ccci-lint):
+```
+$ nix develop .#lint --command bash scripts/lint.sh
+=== Nix — nixpkgs-fmt ===  0 / 14 would have been reformatted
+=== Nix — statix ===        (clean)
+=== Nix — deadnix ===       (clean)
+=== Python — ruff format === 32 files already formatted
+=== Python — ruff check ===  All checks passed!
+=== Shell — shfmt/shellcheck === (clean)
+=== YAML — yamllint ===     (clean)
+lint: PASS
+```
+nix eval `.#nixosConfigurations.cc-ci.config.system.build.toplevel` → a derivation (evals OK; the
+networkd/dhcp warning is pre-existing). Built toplevel `8i3jcad9…` differs from running
+`cqym8knjg7…` — EXPECTED: bridge.py/dashboard.py (and runner) are `cp`'d into the store, so the
+reformat changes their hash. cc-ci will be rebuilt to the formatted closure in W2 before RL3.
+All Python byte-compiles (store python 3.12.8).
+
+Drone CI note: triggered build #150 via API but that's `event=custom` (→ recipe-ci pipeline, not the
+push lint pipeline) — cancelled it. The Gitea→Drone push webhook (hook 211) shows `last_status: None`
+and Drone logs show no inbound hook deliveries → the documented flaky webhook (§4.1). Public and
+canonical (100.90.116.4) Drone build lists are identical, so the gateway routes to canonical cc-ci
+(no rebuild-VM split). Recorded the flaky-webhook as a pre-existing infra item in DECISIONS.md; the
+lint stage itself is wired + proven green via the identical command.
+
+Claimed W0 gate (RL1) in STATUS-1b. Next: W1 white-box review checklist over the cleaned codebase.
diff --git a/STATUS-1b.md b/STATUS-1b.md
index 978576b..4f2b8a2 100644
--- a/STATUS-1b.md
+++ b/STATUS-1b.md
@@ -21,11 +21,19 @@ REVIEW-1b, then `## DONE`.
       deviations in DECISIONS.md.
 
 ## In flight
-**W0 — tooling + format.** Starting: add formatters/linters + `lint` entrypoint + devshell; format
-codebase; wire `.drone.yml` lint stage.
+**W0 — tooling + format: BUILT, self-verified.** Added the `lint` devshell + `scripts/lint.sh` +
+ruff/yamllint config (built from pinned nixpkgs); auto-formatted + lint-cleaned the whole codebase
+(ruff/nixpkgs-fmt/statix/deadnix/shfmt); wired the `lint` stage into the `.drone.yml` push pipeline
+(FAIL on unclean). `scripts/lint.sh` → **lint: PASS** on a clean checkout on cc-ci; the
+nixosConfiguration still evaluates and all Python byte-compiles.
+Note: the Gitea→Drone push webhook is flaky (pre-existing, §4.1) so a push doesn't reliably
+auto-create a Drone build; the stage is proven green via the exact `nix develop .#lint` command the
+stage runs. Next: claim the W0 gate for the Adversary, start W1 (review checklist).
 
 ## Gate
-(none yet)
+**W0 CLAIMED, awaiting Adversary** (RL1). Acceptance: from a clean checkout,
+`nix develop .#lint --command bash scripts/lint.sh` → `lint: PASS`; the stage is in `.drone.yml`'s
+push pipeline.
 
 ## Blocked
 (none)