diff --git a/active.md b/active.md
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+++ b/active.md
@@ -1,5 +1,18 @@
 # Active Tasks
 
+## blackjax-16-upgrade-smoke
+- issue: https://github.com/PyAutoLabs/autolens_profiling/issues/142
+- session: Claude Code cloud/mobile (no local worktree)
+- status: library-dev
+- worktree: none — cloud session works on the GitHub clone directly
+- repos:
+  - autolens_profiling: feature/blackjax-16-upgrade-smoke
+- prompt: active/blackjax_16_upgrade_smoke.md
+- note: Phase 0(b) / CP-2 environment half, CPU-only (human-directed): blackjax
+  >=1.6.2 install validation, blackjax.nss 2D-toy smoke with analytic logZ check,
+  af.BlackJAXNUTS 1.6 API check + PyAutoFit blackjax-cap check. GPU MGE smoke and
+  local/RAL venv upgrades stay laptop work.
+
 ## stored-sample-reconstruction-guard
 - issue: https://github.com/PyAutoLabs/PyAutoFit/issues/1486
 - status: library-dev — WORKSPACE HALF SHIPPED; the PyAutoFit hardening (#1486) is what remains
diff --git a/active/blackjax_16_upgrade_smoke.md b/active/blackjax_16_upgrade_smoke.md
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+# Phase 0(b): validate blackjax ≥1.6.2 + mainline NSS smoke + BlackJAXNUTS 1.6 API check
+
+Type: maintenance
+Target: autolens_profiling
+Repos:
+- @autolens_profiling
+Difficulty: small
+Autonomy: supervised
+Priority: high
+
+Phase 0(b) of the inference programme
+(`autolens_profiling/results/notes/inference/PROGRAMME.md`) — the
+environment-validation half of critical-path item CP-2, runnable on CPU in a
+cloud session (human-directed 2026-08-18: "no need for laptop as not actually
+doing gpu runs for profiling just getting install type stuff working"). The
+GPU MGE smoke half of CP-2 stays laptop work.
+
+Task:
+- Install blackjax ≥1.6.2 with CPU JAX in a clean venv; record the resolved
+  versions and any dependency friction.
+- Smoke `blackjax.nss` on a 2D toy with an analytic evidence check (Gaussian
+  likelihood × uniform prior → known logZ), using the mainline API
+  (native-space `logprior_fn`, `num_delete`, dlogz termination, ensemble
+  logZ error via `utils.finalise`) — the API shape Phase 2's
+  profiling-local runner will wire.
+- Install released `autofit` alongside blackjax 1.6 and check
+  `af.BlackJAXNUTS` against the 1.6 API (import + tiny CPU fit on a toy
+  likelihood). Check whether PyAutoFit's requirements cap blackjax below
+  1.6 — a cap is a source finding for the §7 change list.
+- Record findings in
+  `results/notes/inference/phase_00_unblocking/RESULTS.md` (created by this
+  task) and update the PROGRAMME phase-state table: 0(b) validated on cloud
+  CPU, local venv + RAL stack upgrades remaining.
+
+No profiling conclusions from any timing observed here (wrong tier, CPU toy
+scale); this is install/API validation only.