diff --git a/CHANGELOG.md b/CHANGELOG.md
index a872a7b..9e980a6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,68 @@ All notable changes to fs-cortex will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## [4.5.0] — 2026-07-05
+
+**Installer reliability.** A sandboxed 6-agent audit ran the installer against
+three scenarios — fresh install, upgrade over realistic v3.37 data, v4 refresh
+— and confirmed two real data-loss bugs plus a Windows corruption set. All
+fixed; the v3-data migration path came back clean (v4 code self-heals legacy
+formats lazily) and is now documented. Implementation: Codex (spec-driven),
+verified inline.
+
+### Security
+- `install.ps1`: the backup-archive path-traversal guard regex was
+  over-escaped in a single-quoted string and never matched `../` entries —
+  fixed to match install.sh's semantics (`(^/|\.\.)`), validated at prompt
+  time with `tar -tzf` like the bash installer.
+
+### Fixed
+- **`install.sh`/`install.ps1`: CLAUDE.md user content after the Cortex
+  section was deleted on every rerun** (confirmed twice in the audit — the
+  section-replace regex swallowed to the next heading OR EOF). The section
+  now ships with a `<!-- cortex:end -->` marker and the replace stops there;
+  legacy sections without the marker anchor on the known final section line
+  and never swallow to EOF (explicit warn if neither matches).
+- **`install.sh`/`install.ps1`: a user hook sharing a settings.json handler
+  entry with a cortex hook was silently dropped** — the merge now filters at
+  hook level and only drops entries left empty.
+- `install.sh`: interrupted installs (hooks copied, no `version` file) hit a
+  silent legacy branch that bypassed the downgrade guard — now warned as
+  "proceeding as repair"; Step 11 (CLAUDE.md) failures no longer abort the
+  run under `set -e`, so the version marker is always reached.
+- `install.sh` Step 8b deployed the STALE `githooks/pre-push` (75 lines)
+  instead of `.githooks/pre-push` (149 lines, the real hook used via
+  `core.hooksPath`) — fixed and the stale directory removed.
+- `install.ps1` (Windows corruption set): embedded Python now opens
+  CLAUDE.md/JSON with explicit UTF-8 (locale cp1252 mojibaked every
+  multibyte char); settings hooks written with the DETECTED interpreter
+  (`python` vs hardcoded `python3` — hooks never ran on stock Windows
+  Python); backup import semantics matched to install.sh (memory/reflexes
+  OVERWRITE from backup — was dead code; registry/instincts/evolved/daily
+  no-clobber — was `-Force`; `evolved/` now `-Recurse`); `$LASTEXITCODE`
+  checked after every native call (settings-merge failure no longer prints
+  success); `.repo-path` written so the deploy-drift guard works on Windows;
+  JSON migrations atomic (temp + `Move-Item`); memory version floor no
+  longer rewinds 2-part versions (`'4.0'` → 3.12.0 bug).
+- `install.sh`: `reflexes.json` migration writes atomically (tmp + rename).
+
+### Added
+- **v3→v4 adapter** in both installers: upgrading from < 4 seeds
+  `.last-learn-count` from the existing observation count, so the
+  SessionStart observations banner counts since-upgrade instead of the
+  entire v3 history.
+- `docs/MIGRATION-V4.md` §"Automatic v3-data adaptation (v4.5.0)": what
+  self-heals, what resets by design, what needs action (CORTEX_DEBUG for
+  silently-skipped hollow YAMLs, 30d TTL on legacy pending proposals,
+  v3-era cron jobs on deprecated commands are no-ops).
+- `core/memory.template.json` version 3.12.0 → 4.0.0 (release rule §2b).
+
+### Tests
+- `test_install` 42→49 (user tail survives rerun, mixed-entry user hook
+  survives, v3 upgrade seeds marker, repair warning), `test_install_ps1`
+  10→18 (interpreter, traversal regex, `.repo-path`, UTF-8, import
+  semantics, marker contract — runs on windows-latest CI).
+
 ## [4.4.0] — 2026-07-05
 
 **`/cx-curate` — the semantic curator.** Automates the judgment `/cx-downvote`
diff --git a/core/claudemd-section.md b/core/claudemd-section.md
index 533d8b7..83429e8 100644
--- a/core/claudemd-section.md
+++ b/core/claudemd-section.md
@@ -10,3 +10,4 @@ Cortex observes sessions and distills knowledge in 3 levels:
 
 ### Data: ~/.claude/cortex/
 ### Laws inject automatically. Instincts inject per tool use. No action needed.
+<!-- cortex:end -->
diff --git a/core/memory.template.json b/core/memory.template.json
index 6ad2196..fb6fb4f 100644
--- a/core/memory.template.json
+++ b/core/memory.template.json
@@ -1,5 +1,5 @@
 {
-  "version": "3.12.0",
+  "version": "4.0.0",
   "config": {
     "max_observations_mb": 10,
     "archive_days": 30,
diff --git a/docs/FEATURES.md b/docs/FEATURES.md
index 21eecad..557f0b6 100644
--- a/docs/FEATURES.md
+++ b/docs/FEATURES.md
@@ -1,4 +1,4 @@
-# fs-cortex v4.4.0 — Feature Reference
+# fs-cortex v4.5.0 — Feature Reference
 
 > Complete inventory of all features, commands, hooks, modules, and capabilities.
 > Last updated: 2026-07-05
@@ -367,6 +367,14 @@ Deterministic rules via hooks — not probabilistic instructions. Triggers are r
 - **Bash** (macOS/Linux): `bash install.sh`
 - **PowerShell** (Windows): `powershell -ExecutionPolicy Bypass -File install.ps1`
 
+### Reliability (v4.5.0 — sandboxed audit of fresh/v3-upgrade/v4-refresh)
+- **CLAUDE.md section replace is loss-proof**: the section ships with a `<!-- cortex:end -->` marker and the replace stops there; legacy sections (no marker) anchor on the known final line and NEVER swallow to EOF — user content after the section survives every rerun (previously deleted, confirmed bug)
+- **settings.json merge filters at hook level**: a user hook sharing a handler entry with a cortex hook survives (previously the whole entry was dropped)
+- **Interrupted installs self-identify**: hooks dir present without `version` file → "proceeding as repair" warning instead of the silent legacy branch that bypassed the downgrade guard; Step 11 failures no longer abort mid-run
+- **v3→v4 adapter**: upgrading from < 4 seeds `.last-learn-count` from the existing observation count (kills the lifetime-count banner); full adaptation notes in `docs/MIGRATION-V4.md`
+- **Windows parity + corruption fixes** (install.ps1): explicit UTF-8 in every embedded Python (no more cp1252 mojibake of CLAUDE.md), hooks written with the DETECTED interpreter (`python` vs `python3`), backup import overwrite/no-clobber semantics matched to install.sh (+ `evolved/` recursed), path-traversal regex actually rejects `../`, `$LASTEXITCODE` checked after every native call, `.repo-path` written (deploy-drift guard now works on Windows), atomic JSON migrations
+- `reflexes.json` migration writes atomically (tmp + rename); pre-push hook installs from `.githooks/` (the stale `githooks/` copy is gone)
+
 ### Smart Upgrade
 - Version detection via `~/.claude/cortex/version`
 - Shows upgrade path (e.g., "v3.0.0 → v3.6.0")
@@ -417,7 +425,7 @@ Deterministic rules via hooks — not probabilistic instructions. Triggers are r
 | `test_session_learner.sh` | 61 | Error-fix pairs, corrections, chains, proposals, command timeline; **v3.36.1**: semantic fix summary, hollow-fix skip, writeProposals quality gate; **v3.37.0**: err_msg required, input-derived trigger validation, project scope, evidence samples, agent-pattern scoped trigger; **v3.37.1**: rejection tombstones; **v3.37.2**: isError guards + WebFetch 200-OK no-proposal e2e; **v4.0.0**: draft/confirmed lifecycle; **v4.3.0**: `cx-maintain-ttl` accepted as tombstone rejecter |
 | `test_injector.sh` | 29 | Sanitization, ReDoS, limits, markers, yaml-utils, .last-instinct, engine; **v3.36.1 e2e**: category domain injects with detected stack, hollow action never injects; **v3.37.0 e2e**: per-session repeat cooldown (max 2 + suppress events), token-budget degrade keeps highest-confidence, concurrent-injector count integrity |
 | `test_yaml_utils.sh` | 16 | Floats, ints, strings, colon values, update, list; **v3.36.1**: literal/folded/last-field block scalars |
-| `test_install.sh` | 42 | Fresh install, upgrade, idempotency, **strict** path traversal (no fake-green), **v3.19.0 env merge** (CORTEX_AGENT_DISABLE_REFLEXES added, user vars preserved, idempotency, opt-out respected) |
+| `test_install.sh` | 49 | Fresh install, upgrade, idempotency, **strict** path traversal (no fake-green), **v3.19.0 env merge** (CORTEX_AGENT_DISABLE_REFLEXES added, user vars preserved, idempotency, opt-out respected); **v4.5.0**: user tail after CLAUDE.md section survives rerun (marker), user hook sharing entry with cortex hook survives merge, v3 upgrade seeds `.last-learn-count`, interrupted install → "proceeding as repair" |
 | `test_hooks_e2e.sh` | 14 | Full pipeline: observe→inject→learn, **token budget reset** |
 | `test_uninstall.sh` | 13 | Cleanup, backup creation, data preservation, **safety guard**, CLAUDE.md preservation, **v3.19.0 env removal** (Cortex var removed, user vars preserved, empty env block dropped) |
 | `test_integrity.sh` | 14 | observe.py direct, **21 commands** validated (EXPECTED_COMMANDS subset; 24 command files total as of v4.0.0 — `ls commands/*.md` — incl. new `cx-maintain`/`cx-review` not yet in EXPECTED_COMMANDS), core file schemas, **version consistency** |
@@ -426,7 +434,7 @@ Deterministic rules via hooks — not probabilistic instructions. Triggers are r
 | `test_curate.sh` | 6 | **(v4.4.0)** `apply_confidence_downvote` (reduce+log, 0.30 floor, unknown id), `curate_snapshot()` shape on seeded sandbox, `curate_due()`/`touch_curate_marker()` gating, `curate-snapshot` CLI prints valid JSON |
 | `test_injector_v4.sh` | 13 | **(v4.0.0)** `status: draft` never injects, `status: confirmed`/legacy-no-field inject normally, subtopic dedup + domain soft-ceiling at conf>=0.85, JSON-fragment + prompt-injection action guards, degenerate-trigger static validation, live `reflexes.json` polling conditions |
 | `test_cx_maintain_runner.sh` | 10 | **(v4.0.0, inventoried v4.2.2)** `bin/cx-maintain.sh` hermetic sandbox: exit 0 on repeated runs, decay exactly-once (same-day idempotency via `last_decay_at`), compat markers, valid `.review-digest.json`, no leftover lock dir, `--dry-run` writes nothing; **v4.2.2**: learn markers reset (`.last-learn-count` snapshot, `.obs-count` zeroed, `.learn-pending` cleared); **v4.3.0**: engine-pass report carries `swapped=`/`expired=` counters |
-| `test_install_ps1.ps1` | 10 | PowerShell syntax, version consistency, security features, backup categories, hook config, v3.26-v3.28 source files present, **CI on windows-latest** |
+| `test_install_ps1.ps1` | 18 | PowerShell syntax, version consistency, security features, backup categories, hook config, v3.26-v3.28 source files present, **CI on windows-latest**; **v4.5.0**: detected-interpreter hooks (no hardcoded python3), traversal regex rejects `../`, `.repo-path` write, UTF-8 in embedded Python, backup overwrite/no-clobber semantics, `<!-- cortex:end -->` marker contract |
 | `test_impact.sh` | 32 | **Sprint 0/1 funnel** — schema v1, JS↔Python compat, concurrent writes (10 parallel → 0 loss), rotation, gate GO/NO-GO, formulas, input validation, **v3.17.0 source split** (user/agent ratios, gate input, legacy default), **v3.18.0 auto-eval** (3 evaluator types, no-evaluator default, reflex iid prefix) |
 | `test_cross_day_tracker.sh` | 10 | Roundtrip, boost tiers (1/2/4/8 days), confidence cap 0.95, Jaccard match, single-token guard, prune >365d, concurrent append |
 | `test_detectors_v327.sh` | 12 | detectAgentSubtypes (emit/no-emit/rate), detectFileCoupling (emit/no-emit/missing-path, `::` in paths), detectTimeOfDayPatterns (buckets, empty, merge, reflect JSON structure, corrupted-file no-clobber) |
@@ -672,6 +680,7 @@ locally (not installed to `~/.claude/`):
 | v4.0.0 | 2026-07-02 | **"Signal-first, zero-decision" — full redesign of capture and command set.** `docs/DESIGN-V4.md` + `docs/SPEC-PORT-SINAPSIS.md` (port of Sinapsis v4.6.1, MIT, Luis Salgado). **BREAKING:** 17 of 24 commands deprecated to notice-only stubs (mapping in `docs/MIGRATION-V4.md`); 7 remain active (`cx-status`, `cx-maintain`, `cx-review`, `cx-eod`, `cx-gotcha`, `cx-backup`, `cx-restore`). New `/cx-maintain` (deterministic, cron-able: decay+purge+auto-validate+deterministic law-promotion+Jaccard dedup-by-subtopic+storage rotation+proposals↔instincts reconciliation+health check, writes `.review-digest.json`). New `/cx-review` (the only command with human judgment, weekly, fuses old validate+evolve-confirm+downvote+distill-swap into one shorthand pass). `hooks/observe.py`: per-line capture guards before trusting an error match (`[codex]`/npm-log prefixes, version listings, grep headers, `0 errors`, bare `warning:`), `output` cap 8000→10000, `err_msg` now the first non-guarded matching line. New `status: draft`/`confirmed` instinct lifecycle (`session-learner.js`, `injector-engine.js`) — drafts track silently, auto-promote at `occurrences>=5 AND sessions_seen>=3`; legacy instincts default `confirmed`. Law promotion gate replaced with a fully deterministic one (`conf>=0.95`, `projects_seen>=3`, `occurrences_v4>=10` via lazy `occurrences_legacy` migration, 0 noise 14d) — `auto-distill-candidates.md` buzón removed. Injector: JSON-fragment + prompt-injection guards at load, degenerate-trigger static validation, dedup switched from per-domain to per-subtopic (2 first words of id) with a soft 2-per-domain ceiling at conf>=0.85. `core/_cx-eod-gather.sh`: per-project `context` field, `[eod-eisenhower]` Q1-Q4 keyword classification of "for tomorrow" bullets, review-digest pending count surfaced. New test suites `test_distill_v4.sh` (6/6 PASS), `test_injector_v4.sh` (13/13 PASS). |
 | v4.1.0 | 2026-07-04 | **Audit hardening (multi-agent audit + adversarial verify).** `session-start.py` injects full law text (not just line 1). `session-learner.js`: tombstone gate matches by trigger vs `proposals-history.jsonl`, dup-trigger dedup, `$HOME`→`~` paths, head+tail sampling. Reflexes: re-enabled `python3-bypass-write-tool`, hardened `bash-cat-use-read`. `storage-rotation.js`: prunes `cross-day-tracker` past 1.5× threshold, stale `.lock`/`.bak` cleanup, `timeline.jsonl` rotation. `distill_engine.py`: `prune_instinct_tracking()` + `reap_stale_nudge_state()` + CLI subcommands. `injector-engine.js`: session token budget 8000→12000 with a visible suppression warning, optional per-reflex `domains` filter. |
 | v4.2.0 | 2026-07-05 | **Laws layer: de-dup, tier legibility, post-promotion audit** (`docs/DESIGN-laws-v4.2.md`; 3-agent adversarial pass). Fixed double injection (`read-instructions` 41×, `pref-fix` 17× redundant PreToolUse) — `injector-engine.js` skips instinct candidates with a `laws/{id}.txt` twin; `manual_swap_promote` archives the source instinct like `auto_promote_to_law`. `advisor-escalation` trimmed 1505→717 chars. Reverted the v4.1.0 `bash-cat-use-read` lookahead regression (broke `test_reflex_matchers`). Added law presentation split by tier (`[principios]`/`[herramienta]`, `core/laws-meta.default.json`) + `law_audit()` + `law-audit` CLI. |
+| v4.5.0 | 2026-07-05 | **Installer reliability — sandboxed audit of fresh install, v3-data migration and v4 refresh (6-agent workflow + Codex implementation).** Confirmed data-loss bugs fixed: CLAUDE.md user content after the Cortex section deleted on every rerun (now marker-bounded `<!-- cortex:end -->` + legacy anchor, never swallows to EOF); user hook sharing a settings entry with a cortex hook dropped (now hook-level filter). Half-install hardening: Step 11 failures no longer abort; missing version file → "proceeding as repair" instead of silently bypassing the downgrade guard. v3→v4 adapter seeds `.last-learn-count`; `docs/MIGRATION-V4.md` documents self-heals / by-design resets / action-needed. Windows: UTF-8 everywhere (cp1252 mojibake fix), detected-interpreter hooks, backup import semantics matched to sh (+ evolved/ recursed), traversal regex fixed, `$LASTEXITCODE` checked, `.repo-path` (drift guard live on Windows), atomic migrations. Stale `githooks/` removed (pre-push installs from `.githooks/`). `core/memory.template.json` → 4.0.0. `test_install` 42→49 (audit had found the table stale at 42 vs 44 real), `test_install_ps1` 10→18. |
 | v4.4.0 | 2026-07-05 | **`/cx-curate` — semantic curator; `/cx-downvote` judgment automated.** The LLM half of zero-touch: Claude classifies laws (generality, redundancy vs CLAUDE.md/skills, value-per-token), demotes niche laws via the v4.3.1 cascade, promotes only trigger-less knowledge, downvotes broken instincts (`apply_confidence_downvote`, floor 0.30). Weekly `.last-curate` cadence; `[CURATE] due` banner auto-triggers execution. Engine: `curate_snapshot()` + CLI `curate-snapshot`/`downvote`, `curate_due()`/`touch_curate_marker()`, `CURATE_*` constants. Born validated: a 29-agent semantic audit recomposed the live constitution the same day (6 laws demoted to instincts; 0 promotions — every top candidate already lived as a 0.99 trigger-gated instinct, a finding folded into the PROMOTE criterion; 10 broken instincts downvoted; cap 15/15 → 9/15). Implemented by 3 parallel subagents + integration verifier. `test_curate` new 6, `test_session_start` 11→14. Active commands 7→8; `core/claudemd-section.md` refreshed to the v4 set (stale since v4.0.0). |
 | v4.3.1 | 2026-07-05 | **Retired laws cascade to instincts (operator feedback on v4.3.0).** Auto-swap retirement and `demote_law_to_domain` share `_restore_backing_instinct()`: the victim's backing YAML returns to `instincts/global/` with `law_eligible: false` (no re-promotion ping-pong), keeping the knowledge injecting via PreToolUse and subject to normal decay. Fixes the two-layer loss (promotion archives the instinct; retirement used to archive the law → knowledge gone from both). Also fixes `demote_law_to_domain`'s lookup, blind to the `<id>.promoted-to-law-<date>.yaml` name every v4 promotion writes. No-backing laws stay archive-only (never invent a trigger). `test_distill_v4` 10→12. |
 | v4.3.0 | 2026-07-05 | **Zero-touch mode — the pipeline never waits on a human.** Reverts the v4.2 "human prunes" model at the operator's request. (1) `auto_promote_to_law` auto-swaps at a saturated cap: victim = `_find_least_impactful_law` (lowest useful/(1+noise) 14d), age >= 30d (`LAW_AUTO_SWAP_MIN_AGE_DAYS`), max 2 swaps/run, only when the cap is the sole failing gate; executes via `_swap_promote_unlocked` (extracted from `manual_swap_promote` — calling the locked wrapper from inside the maintain lock would deadlock on the shared flock). (2) `expire_stale_proposals()`: pending human-gated proposals older than 30d (`PROPOSAL_TTL_DAYS`) auto-reject as `cx-maintain-ttl` (added to both tombstone whitelists — never resurrect). (3) SessionStart badge informative: `[cx] maintain: +law (jubilada X), N caducadas, M en cola` from digest `swaps_last_run`/`expired_last_run`, silenced 48h after the pass; the imperative `[REVIEW] N items -> /cx-review` badge is gone. (4) `/cx-review` reframed as optional veto pass. Shared `_archive_promoted_instinct_source` helper dedups 3 archive sites. `test_distill_v4` 6→10, `test_session_start` 7→11, `test_session_learner` 60→61, runner report carries `swapped=`/`expired=`. Implementation delegated to Codex GPT-5.3 (spec-driven), reviewed inline. |
diff --git a/docs/MIGRATION-V4.md b/docs/MIGRATION-V4.md
index 912918d..83d8bf6 100644
--- a/docs/MIGRATION-V4.md
+++ b/docs/MIGRATION-V4.md
@@ -92,6 +92,47 @@ touches a given file.
   `agent-evolution`, `error-recovery`) accumulate for `/cx-review`; the rest
   auto-validate inside `/cx-maintain`.
 
+## Automatic v3-data adaptation (v4.5.0)
+
+The installer and runtime were audited end-to-end against a realistic v3.37
+data tree (sandboxed fresh install, v3-data upgrade, v4 re-install). Summary
+of what a v3.x user gets, grouped by outcome:
+
+**Self-heals (no action needed)**
+
+- Legacy instincts without `status` inject as `confirmed`; `occurrences` is
+  preserved as `occurrences_legacy` (see the section above).
+- Missing `laws/laws-meta.json` is tolerated — every law defaults to tier
+  `principle` and SessionStart renders normally (`load_laws` is tolerant of a
+  missing or malformed meta file since v4.2.1).
+- Missing v4 artifacts (`.review-digest.json`, `proposals-history.jsonl`,
+  `instinct-tracking.json`, `.last-curate`) are created lazily by the first
+  `/cx-maintain` / learner run that needs them.
+- **`.last-learn-count` is seeded by the installer** (v4.5.0) from your
+  existing observation count when upgrading from < 4, so the SessionStart
+  "N+ new observations" banner counts since-upgrade instead of your entire
+  v3 history.
+
+**By-design resets (expected, not bugs)**
+
+- Law-promotion maturity clocks restart: the deterministic gate counts
+  `occurrences_v4` from zero and requires 3+ distinct projects again
+  (`LAW_MIN_PROJECTS` was 1 in late v3).
+- Legacy rejected proposals in `proposals-history.jsonl` become permanent
+  tombstones — previously rejected patterns will not resurface as pending.
+
+**Degrades silently / action needed**
+
+- Hollow or corrupt legacy instinct YAMLs (action < 30 chars, raw-JSON
+  fragments, unparseable frontmatter) are skipped at injection with no
+  operator-visible signal. Run a session with `CORTEX_DEBUG=1` to list the
+  skipped files, or delete/fix them.
+- Pending v3 proposals in human-gated domains expire after 30 days
+  (`PROPOSAL_TTL_DAYS`, v4.3.0) unless reviewed via `/cx-review`.
+- v3-era cron/launchd jobs invoking deprecated commands (`/cx-distill`,
+  `/cx-dream`, `/cx-analyze`, `/cx-validate`) exit 0 while doing nothing —
+  reschedule them to `bin/cx-maintain.sh` (see "Scheduling" below).
+
 ## Deterministic law promotion (replaces manual Criteria 8)
 
 A law now promotes automatically, with no `law_eligible: true` flag to set by
diff --git a/githooks/pre-push b/githooks/pre-push
deleted file mode 100755
index d9f29fe..0000000
--- a/githooks/pre-push
+++ /dev/null
@@ -1,75 +0,0 @@
-#!/usr/bin/env bash
-# Pre-push hook: block pushes to main without version bump + changelog update
-#
-# Checks that CHANGELOG.md was modified in the commits being pushed.
-# Skips check for non-main branches (feature branches can push freely).
-
-set -euo pipefail
-
-remote="$1"
-
-while read -r local_ref local_oid remote_ref remote_oid; do
-    # Only enforce on main/master
-    case "$remote_ref" in
-        refs/heads/main|refs/heads/master) ;;
-        *) continue ;;
-    esac
-
-    # If remote_oid is all zeros, it's a new branch — compare against root
-    if [ "$remote_oid" = "0000000000000000000000000000000000000000" ]; then
-        range="$local_oid"
-    else
-        range="${remote_oid}..${local_oid}"
-    fi
-
-    # Check if CHANGELOG.md was modified in the commits being pushed
-    changelog_changed=$(git diff --name-only "$range" -- CHANGELOG.md 2>/dev/null | wc -l | tr -d ' ')
-
-    if [ "$changelog_changed" -eq 0 ]; then
-        echo ""
-        echo "❌ PUSH BLOCKED: No CHANGELOG.md changes detected."
-        echo ""
-        echo "   Before pushing to main, you must:"
-        echo "   1. Bump version (patch/minor/major) in CHANGELOG.md"
-        echo "   2. Add a changelog entry describing the changes"
-        echo "   3. Update version in skills/cortex/SKILL.md if minor/major"
-        echo ""
-        echo "   To bypass (emergencies only): git push --no-verify"
-        echo ""
-        exit 1
-    fi
-
-    # Check version consistency across all sources (v3.15.0+)
-    if [ -f "scripts/check-version-consistency.py" ]; then
-        if ! python3 scripts/check-version-consistency.py --quiet; then
-            echo ""
-            python3 scripts/check-version-consistency.py || true
-            echo ""
-            echo "❌ PUSH BLOCKED: version drift between install.sh / install.ps1 / CHANGELOG.md / docs/FEATURES.md"
-            echo "   Fix the versions above and retry."
-            exit 1
-        fi
-    fi
-
-    # Check that tests exist and pass
-    if [ -f "tests/test_security.sh" ]; then
-        echo "Running security tests..."
-        if ! bash tests/test_security.sh > /dev/null 2>&1; then
-            echo "❌ PUSH BLOCKED: Security tests failed."
-            exit 1
-        fi
-    fi
-
-    if [ -f "tests/test_dream_cycle.sh" ]; then
-        echo "Running dream cycle tests..."
-        if ! bash tests/test_dream_cycle.sh > /dev/null 2>&1; then
-            echo "❌ PUSH BLOCKED: Dream cycle tests failed."
-            exit 1
-        fi
-    fi
-
-    echo "✅ Pre-push checks passed (changelog updated, tests green)"
-
-done
-
-exit 0
diff --git a/install.ps1 b/install.ps1
index ce12aa9..04928e7 100644
--- a/install.ps1
+++ b/install.ps1
@@ -20,7 +20,7 @@ $CommandsDir = Join-Path $ClaudeDir "commands"
 $HooksDir = Join-Path (Join-Path $ClaudeDir "hooks") "cortex"
 $SettingsFile = Join-Path $ClaudeDir "settings.json"
 $ClaudeMd = Join-Path $ClaudeDir "CLAUDE.md"
-$NewVersion = "4.4.0"
+$NewVersion = "4.5.0"
 
 # v3.25.1 — explicit downgrade flag (parity with install.sh).
 # A behind-remote repo would silently rewind hooks otherwise.
@@ -30,7 +30,15 @@ $AssumeYes = ($args -contains '-y') -or ($args -contains '--yes') -or ($args -co
 function Test-VersionLessThan {
     param([string]$A, [string]$B)
     try {
-        return [version]$A -lt [version]$B
+        $aParts = @($A -split '\.' | ForEach-Object { if ($_ -match '^\d+$') { [int]$_ } else { 0 } })
+        $bParts = @($B -split '\.' | ForEach-Object { if ($_ -match '^\d+$') { [int]$_ } else { 0 } })
+        for ($i = 0; $i -lt 3; $i++) {
+            $av = if ($i -lt $aParts.Count) { $aParts[$i] } else { 0 }
+            $bv = if ($i -lt $bParts.Count) { $bParts[$i] } else { 0 }
+            if ($av -lt $bv) { return $true }
+            if ($av -gt $bv) { return $false }
+        }
+        return $false
     } catch {
         # Non-semver fallback: string compare
         return $A -lt $B
@@ -158,6 +166,13 @@ if ((-not $HasCortex) -and (-not $AssumeYes) -and (-not [Console]::IsInputRedire
         Print-Warn "Not a valid file: $ImportBackup - skipping backup import"
         $ImportBackup = ""
     }
+    elseif ($ImportBackup) {
+        tar -tzf $ImportBackup *> $null
+        if ($LASTEXITCODE -ne 0) {
+            Print-Warn "Not a valid .tar.gz archive - skipping backup import"
+            $ImportBackup = ""
+        }
+    }
 }
 
 # Step 4: Create directory structure
@@ -190,14 +205,14 @@ else {
     Print-Warn "memory.json exists, preserving user data"
     # Migrate memory.json: remove dead identity block, update version (v3.12.0+)
     try {
-        $memJson = Get-Content $memoryDest -Raw | ConvertFrom-Json
+        $memJson = Get-Content $memoryDest -Raw -Encoding UTF8 | ConvertFrom-Json
         $changed = $false
         if ($memJson.PSObject.Properties.Name -contains 'identity') {
             $memJson.PSObject.Properties.Remove('identity')
             $changed = $true
         }
-        $curVer = ($memJson.version -split '\.') | ForEach-Object { [int]$_ }
-        if ($curVer.Count -lt 3 -or $curVer[0] -lt 3 -or ($curVer[0] -eq 3 -and $curVer[1] -lt 12)) {
+        $curRaw = if ($memJson.PSObject.Properties.Name -contains 'version') { [string]$memJson.version } else { "0.0.0" }
+        if (Test-VersionLessThan $curRaw "3.12.0") {
             $memJson.version = '3.12.0'
             $changed = $true
         }
@@ -231,8 +246,8 @@ else {
     # Migrate reflexes: add new + update matcher/condition/action (v3.10.6+)
     # Preserves user runtime data: fireCount, lastFired, enabled
     try {
-        $userReflexes = Get-Content $reflexesDest -Raw | ConvertFrom-Json
-        $defaultReflexes = Get-Content ([IO.Path]::Combine($ScriptDir, "core", "reflexes.default.json")) -Raw | ConvertFrom-Json
+        $userReflexes = Get-Content $reflexesDest -Raw -Encoding UTF8 | ConvertFrom-Json
+        $defaultReflexes = Get-Content ([IO.Path]::Combine($ScriptDir, "core", "reflexes.default.json")) -Raw -Encoding UTF8 | ConvertFrom-Json
         $userById = @{}
         foreach ($u in $userReflexes.reflexes) { $userById[$u.id] = $u }
         $added = 0; $updated = 0
@@ -278,7 +293,9 @@ else {
             }
         }
         if ($added -gt 0 -or $updated -gt 0) {
-            $userReflexes | ConvertTo-Json -Depth 10 | Set-Content $reflexesDest -Encoding UTF8
+            $tmpPath = "$reflexesDest.tmp.$PID"
+            $userReflexes | ConvertTo-Json -Depth 10 | Set-Content $tmpPath -Encoding UTF8
+            Move-Item $tmpPath $reflexesDest -Force
             $parts = @()
             if ($added -gt 0) { $parts += "$added new" }
             if ($updated -gt 0) { $parts += "$updated updated" }
@@ -355,6 +372,17 @@ if (Test-Path $libSrc) {
     Print-Ok "Lib modules installed to ~/.claude/hooks/cortex/lib/"
 }
 
+# Step 8b: Install git pre-push hook (version+changelog enforcement)
+$gitDir = Join-Path $ScriptDir ".git"
+$prePushSrc = [IO.Path]::Combine($ScriptDir, ".githooks", "pre-push")
+if ((Test-Path $gitDir -PathType Container) -and (Test-Path $prePushSrc)) {
+    $gitHooksDir = Join-Path $gitDir "hooks"
+    if (Test-Path $gitHooksDir -PathType Container) {
+        Copy-Item $prePushSrc (Join-Path $gitHooksDir "pre-push") -Force
+        Print-Ok "Git pre-push hook installed (version+changelog guard)"
+    }
+}
+
 # Step 9: Install seed instinct (only if not already present)
 Print-Step "Installing seed instinct..."
 $seedDest = [IO.Path]::Combine($CortexDir, "instincts", "global", "read-instructions-before-executing.yaml")
@@ -382,10 +410,11 @@ $pyMerge = @'
 import json, os, tempfile
 
 settings_file = os.path.join(os.environ.get("USERPROFILE", ""), ".claude", "settings.json")
+python_cmd = os.environ.get("CORTEX_INSTALL_PYTHON_CMD", "python")
 
 settings = {}
 if os.path.exists(settings_file):
-    with open(settings_file) as f:
+    with open(settings_file, encoding="utf-8") as f:
         settings = json.load(f)
 
 settings.setdefault("permissions", {})
@@ -402,30 +431,36 @@ if "~/.claude/cortex" not in settings["permissions"].get("additionalDirectories"
 
 cortex_hooks = {
     "SessionStart": [
-        {"hooks": [{"type": "command", "command": "python3 ~/.claude/hooks/cortex/session-start.py", "timeout": 5000}]},
-        {"matcher": "compact", "hooks": [{"type": "command", "command": "python3 ~/.claude/hooks/cortex/session-start.py", "timeout": 5000}]}
+        {"hooks": [{"type": "command", "command": f"{python_cmd} ~/.claude/hooks/cortex/session-start.py", "timeout": 5000}]},
+        {"matcher": "compact", "hooks": [{"type": "command", "command": f"{python_cmd} ~/.claude/hooks/cortex/session-start.py", "timeout": 5000}]}
     ],
     "PreToolUse": [
         {"matcher": "*", "hooks": [
-            {"type": "command", "command": "python3 ~/.claude/hooks/cortex/observe.py pre", "timeout": 10000, "async": True},
+            {"type": "command", "command": f"{python_cmd} ~/.claude/hooks/cortex/observe.py pre", "timeout": 10000, "async": True},
             {"type": "command", "command": "node ~/.claude/hooks/cortex/injector.js", "timeout": 3000}
         ]}
     ],
     "PostToolUse": [
-        {"matcher": "*", "hooks": [{"type": "command", "command": "python3 ~/.claude/hooks/cortex/observe.py post", "timeout": 10000, "async": True}]}
+        {"matcher": "*", "hooks": [{"type": "command", "command": f"{python_cmd} ~/.claude/hooks/cortex/observe.py post", "timeout": 10000, "async": True}]}
     ],
     "Stop": [
         {"hooks": [{"type": "command", "command": "node ~/.claude/hooks/cortex/session-learner.js", "timeout": 15000}]}
     ],
     "PreCompact": [
-        {"hooks": [{"type": "command", "command": "python3 ~/.claude/hooks/cortex/precompact.py", "timeout": 8000}]}
+        {"hooks": [{"type": "command", "command": f"{python_cmd} ~/.claude/hooks/cortex/precompact.py", "timeout": 8000}]}
     ]
 }
 
 existing_hooks = settings.get("hooks", {})
 for event, handlers in cortex_hooks.items():
     existing = existing_hooks.get(event, [])
-    cleaned = [h for h in existing if not any("hooks/cortex/" in str(hook.get("command", "")) for hook in h.get("hooks", []))]
+    cleaned = []
+    for h in existing:
+        kept_hooks = [hook for hook in h.get("hooks", []) if "hooks/cortex/" not in str(hook.get("command", ""))]
+        if kept_hooks:
+            h = dict(h)
+            h["hooks"] = kept_hooks
+            cleaned.append(h)
     existing_hooks[event] = cleaned + handlers
 
 settings["hooks"] = existing_hooks
@@ -441,7 +476,7 @@ if "CORTEX_AGENT_DISABLE_REFLEXES" not in settings["env"]:
 
 fd, tmp_path = tempfile.mkstemp(dir=os.path.dirname(settings_file), suffix='.tmp')
 try:
-    with os.fdopen(fd, 'w') as f:
+    with os.fdopen(fd, 'w', encoding="utf-8") as f:
         json.dump(settings, f, indent=2)
         f.write("\n")
     import stat
@@ -453,7 +488,9 @@ except:
 '@
 
 try {
+    $env:CORTEX_INSTALL_PYTHON_CMD = $PythonCmd
     & $PythonCmd -c $pyMerge
+    if ($LASTEXITCODE -ne 0) { throw "Python exited with code $LASTEXITCODE" }
     Print-Ok "Hooks configured in settings.json"
 }
 catch {
@@ -461,6 +498,9 @@ catch {
     Print-Error "  Inner error: $($_.Exception.Message)"
     exit 1
 }
+finally {
+    Remove-Item Env:CORTEX_INSTALL_PYTHON_CMD -ErrorAction SilentlyContinue
+}
 
 # Step 11: Update CLAUDE.md
 Print-Step "Updating CLAUDE.md..."
@@ -471,52 +511,108 @@ if (Test-Path $ClaudeMd) {
     $claudeBackup = "$ClaudeMd.backup.$(Get-Date -Format 'yyyyMMdd-HHmmss')"
     Copy-Item $ClaudeMd $claudeBackup -ErrorAction SilentlyContinue
 
-    $content = Get-Content $ClaudeMd -Raw
+    $content = Get-Content $ClaudeMd -Raw -Encoding UTF8
     if ($content -match "## Cortex") {
         # UPGRADE: replace existing section
         $pyReplace = @"
 import re, os, tempfile, sys
 claude_md = os.path.join(os.environ.get('USERPROFILE', ''), '.claude', 'CLAUDE.md')
 section_file = sys.argv[1]
-with open(claude_md) as f:
+with open(claude_md, encoding='utf-8') as f:
     content = f.read()
-with open(section_file) as f:
+with open(section_file, encoding='utf-8') as f:
     new_section = f.read()
-content = re.sub(r'\n*## Cortex \(Learning System\)\n.*?(?=\n## |\Z)', '', content, flags=re.DOTALL)
-content = content.rstrip() + '\n\n' + new_section + '\n'
-fd, tmp = tempfile.mkstemp(dir=os.path.dirname(claude_md), suffix='.tmp')
-with os.fdopen(fd, 'w') as f:
-    f.write(content)
-os.replace(tmp, claude_md)
+header = re.search(r'(?m)^## Cortex \(Learning System\)\s*\n', content)
+warn = None
+if header:
+    start = header.start()
+    rest = content[start:]
+    marker = re.search(r'(?m)^<!-- cortex:end -->\s*$', rest)
+    legacy = re.search(r'### Laws inject automatically[^\n]*\n?', rest, flags=re.DOTALL)
+    if marker:
+        end = start + marker.end()
+    elif legacy:
+        end = start + legacy.end()
+    else:
+        next_heading = re.search(r'\n## ', content[header.end():])
+        if next_heading:
+            end = header.end() + next_heading.start()
+        else:
+            end = None
+            warn = 'Cortex section boundary not found; manual cleanup may be needed'
+    if end is not None:
+        if start > 0 and content[start - 1] == '\n':
+            start -= 1
+        content = content[:start].rstrip() + '\n\n' + new_section.rstrip() + '\n' + content[end:].lstrip('\n')
+else:
+    content = content.rstrip() + '\n\n' + new_section.rstrip() + '\n'
+if warn:
+    print('WARN:' + warn, file=sys.stderr)
+else:
+    content = content.rstrip() + '\n'
+    fd, tmp = tempfile.mkstemp(dir=os.path.dirname(claude_md), suffix='.tmp')
+    with os.fdopen(fd, 'w', encoding='utf-8') as f:
+        f.write(content)
+    os.replace(tmp, claude_md)
 "@
-        & $PythonCmd -c $pyReplace $sectionFile
-        Print-Ok "Cortex section updated in CLAUDE.md"
+        $claudeErr = Join-Path $CortexDir ".claudemd-update.err"
+        & $PythonCmd -c $pyReplace $sectionFile 2> $claudeErr
+        if ($LASTEXITCODE -ne 0) {
+            Print-Error "Failed to update Cortex section in CLAUDE.md; continuing"
+        }
+        elseif ((Test-Path $claudeErr) -and ((Get-Content $claudeErr -Raw -ErrorAction SilentlyContinue) -match "WARN:(.*)")) {
+            Print-Warn $Matches[1].Trim()
+        }
+        else {
+            Print-Ok "Cortex section updated in CLAUDE.md"
+        }
+        Remove-Item $claudeErr -Force -ErrorAction SilentlyContinue
     }
     else {
         # FRESH: append
-        Add-Content $ClaudeMd "`n"
-        Get-Content $sectionFile | Add-Content $ClaudeMd
-        Print-Ok "Cortex section appended to CLAUDE.md"
+        try {
+            Add-Content $ClaudeMd "`n" -Encoding UTF8
+            Get-Content $sectionFile -Encoding UTF8 | Add-Content $ClaudeMd -Encoding UTF8
+            Print-Ok "Cortex section appended to CLAUDE.md"
+        }
+        catch {
+            Print-Error "Failed to append Cortex section to CLAUDE.md; continuing"
+        }
     }
 }
 else {
-    Copy-Item $sectionFile $ClaudeMd
-    Print-Ok "Created CLAUDE.md with Cortex section"
+    try {
+        Get-Content $sectionFile -Encoding UTF8 | Set-Content $ClaudeMd -Encoding UTF8
+        Print-Ok "Created CLAUDE.md with Cortex section"
+    }
+    catch {
+        Print-Error "Failed to create CLAUDE.md with Cortex section; continuing"
+    }
 }
 
 # Step 12: Import backup (if provided)
 if ($ImportBackup) {
     Print-Step "Importing backup..."
     Print-Warn "Backup import on Windows requires tar (available in Windows 10+)"
+    $tempDir = $null
     try {
         # Validate archive: reject entries with path traversal or absolute paths
-        $unsafeEntries = tar -tzf $ImportBackup 2>$null | Where-Object { $_ -match '(^\\/|\\.\\.[\\/])' }
+        $entries = tar -tzf $ImportBackup 2>$null
+        if ($LASTEXITCODE -ne 0) {
+            Print-Error "Not a valid .tar.gz archive. Aborting import."
+            throw "IMPORT_ABORTED"
+        }
+        $unsafeEntries = $entries | Where-Object { $_ -match '(^/|\.\.)' }
         if ($unsafeEntries) {
             Print-Error "Backup archive contains unsafe paths (../ or absolute). Aborting import."
-            return
+            throw "IMPORT_ABORTED"
         }
         $tempDir = New-Item -ItemType Directory -Path (Join-Path ([System.IO.Path]::GetTempPath()) ([System.IO.Path]::GetRandomFileName()))
         tar -xzf $ImportBackup -C $tempDir.FullName 2>$null
+        if ($LASTEXITCODE -ne 0) {
+            Print-Error "Failed to extract backup. Continuing with fresh install."
+            throw "IMPORT_ABORTED"
+        }
         # Copy laws
         $lawsDir = Join-Path $tempDir.FullName "laws"
         if (Test-Path $lawsDir) {
@@ -539,20 +635,21 @@ if ($ImportBackup) {
         $memSrc = Join-Path $tempDir.FullName "memory.json"
         if (Test-Path $memSrc) {
             $memDest = Join-Path $CortexDir "memory.json"
-            if (-not (Test-Path $memDest)) { Copy-Item $memSrc $memDest }
+            Copy-Item $memSrc $memDest -Force
         }
         # Copy reflexes.json (user customizations)
         $refSrc = Join-Path $tempDir.FullName "reflexes.json"
         if (Test-Path $refSrc) {
             $refDest = Join-Path $CortexDir "reflexes.json"
-            if (-not (Test-Path $refDest)) { Copy-Item $refSrc $refDest }
+            Copy-Item $refSrc $refDest -Force
         }
         # Copy projects registry
         $regSrc = [IO.Path]::Combine($tempDir.FullName, "projects", "registry.json")
         if (Test-Path $regSrc) {
             $regDir = Join-Path $CortexDir "projects"
             if (-not (Test-Path $regDir)) { New-Item -ItemType Directory -Path $regDir -Force | Out-Null }
-            Copy-Item $regSrc (Join-Path $regDir "registry.json") -Force
+            $regDest = Join-Path $regDir "registry.json"
+            if (-not (Test-Path $regDest)) { Copy-Item $regSrc $regDest }
         }
         # Copy project-scoped instincts
         $projInstDir = Join-Path $tempDir.FullName "projects"
@@ -562,7 +659,10 @@ if ($ImportBackup) {
                 if (Test-Path $projInstSrc) {
                     $projDest = [IO.Path]::Combine($CortexDir, "projects", $_.Name, "instincts")
                     if (-not (Test-Path $projDest)) { New-Item -ItemType Directory -Path $projDest -Force | Out-Null }
-                    Copy-Item "$projInstSrc/*" $projDest -Force -ErrorAction SilentlyContinue
+                    Get-ChildItem "$projInstSrc/*" -File -ErrorAction SilentlyContinue | ForEach-Object {
+                        $dest = Join-Path $projDest $_.Name
+                        if (-not (Test-Path $dest)) { Copy-Item $_.FullName $dest }
+                    }
                 }
             }
         }
@@ -571,20 +671,33 @@ if ($ImportBackup) {
         if (Test-Path $evolvedSrc) {
             $evolvedDest = Join-Path $CortexDir "evolved"
             if (-not (Test-Path $evolvedDest)) { New-Item -ItemType Directory -Path $evolvedDest -Force | Out-Null }
-            Copy-Item "$evolvedSrc/*" $evolvedDest -Force -ErrorAction SilentlyContinue
+            Get-ChildItem "$evolvedSrc/*" -ErrorAction SilentlyContinue | ForEach-Object {
+                $dest = Join-Path $evolvedDest $_.Name
+                if (-not (Test-Path $dest)) {
+                    Copy-Item $_.FullName $dest -Recurse
+                }
+            }
         }
         # Copy daily summaries
         $dailySrc = Join-Path $tempDir.FullName "daily-summaries"
         if (Test-Path $dailySrc) {
             $dailyDest = Join-Path $CortexDir "daily-summaries"
             if (-not (Test-Path $dailyDest)) { New-Item -ItemType Directory -Path $dailyDest -Force | Out-Null }
-            Copy-Item "$dailySrc/*" $dailyDest -Force -ErrorAction SilentlyContinue
+            Get-ChildItem "$dailySrc/*" -File -ErrorAction SilentlyContinue | ForEach-Object {
+                $dest = Join-Path $dailyDest $_.Name
+                if (-not (Test-Path $dest)) { Copy-Item $_.FullName $dest }
+            }
         }
         Print-Ok "Backup imported (all 8 categories)"
         Remove-Item $tempDir.FullName -Recurse -Force -ErrorAction SilentlyContinue
     }
     catch {
-        Print-Error "Failed to extract backup. Continuing with fresh install."
+        if ($_.Exception.Message -ne "IMPORT_ABORTED") {
+            Print-Error "Failed to extract backup. Continuing with fresh install."
+        }
+        if ($null -ne $tempDir -and (Test-Path $tempDir.FullName)) {
+            Remove-Item $tempDir.FullName -Recurse -Force -ErrorAction SilentlyContinue
+        }
     }
 }
 
@@ -596,15 +709,18 @@ if (-not $HasCortex -and -not $ImportBackup) {
     & $PythonCmd -c @'
 import json, os, datetime
 mem_path = os.path.join(os.environ.get("USERPROFILE", ""), ".claude", "cortex", "memory.json")
-with open(mem_path) as f:
+with open(mem_path, encoding="utf-8") as f:
     mem = json.load(f)
 mem["stats"]["installed"] = datetime.datetime.now().strftime("%Y-%m-%d")
 import tempfile
 fd, tmp = tempfile.mkstemp(dir=os.path.dirname(mem_path), suffix=".tmp")
-with os.fdopen(fd, "w") as f:
+with os.fdopen(fd, "w", encoding="utf-8") as f:
     json.dump(mem, f, indent=2)
 os.replace(tmp, mem_path)
 '@ 2>$null
+    if ($LASTEXITCODE -ne 0) {
+        Print-Warn "Could not populate memory.json install date"
+    }
 
     # Copy seed laws
     $seedLawsDir = [IO.Path]::Combine($ScriptDir, "seeds", "laws")
@@ -627,8 +743,9 @@ os.replace(tmp, mem_path)
     }
 }
 
-# Step 14: Write version marker
-Set-Content (Join-Path $CortexDir "version") $NewVersion
+# Step 14: Write version marker + repo path (anti-drift guard)
+Set-Content (Join-Path $CortexDir "version") $NewVersion -Encoding UTF8
+Set-Content (Join-Path $CortexDir ".repo-path") $ScriptDir -Encoding UTF8
 
 # Step 15: Summary
 Write-Host ""
diff --git a/install.sh b/install.sh
index aa9653a..39435d6 100755
--- a/install.sh
+++ b/install.sh
@@ -21,7 +21,7 @@ COMMANDS_DIR="$CLAUDE_DIR/commands"
 HOOKS_DIR="$CLAUDE_DIR/hooks/cortex"
 SETTINGS_FILE="$CLAUDE_DIR/settings.json"
 CLAUDE_MD="$CLAUDE_DIR/CLAUDE.md"
-NEW_VERSION="4.4.0"
+NEW_VERSION="4.5.0"
 
 # v3.25.1 — explicit downgrade flag. The installer is a copy-not-merge of
 # hooks/commands, so running an older `install.sh` over a newer install
@@ -122,6 +122,8 @@ if [ -d "$CORTEX_DIR" ]; then
     # Detect installed version
     if [ -f "$CORTEX_DIR/version" ]; then
         INSTALLED_VERSION=$(cat "$CORTEX_DIR/version" 2>/dev/null | tr -d '[:space:]')
+    elif [ -d "$HOOKS_DIR" ]; then
+        print_warn "Cortex installation state unknown (interrupted install?) — proceeding as repair"
     fi
     # Check if there's actual learned data
     LAW_COUNT=$(find "$CORTEX_DIR/laws" -maxdepth 1 -name "*.txt" 2>/dev/null | wc -l | tr -d ' ')
@@ -249,7 +251,7 @@ else
     # Preserves user runtime data: fireCount, lastFired, enabled
     if command -v python3 >/dev/null 2>&1; then
         python3 -c "
-import json, sys
+import json, os, sys, tempfile
 rpath = '$CORTEX_DIR/reflexes.json'
 dpath = '$SCRIPT_DIR/core/reflexes.default.json'
 try:
@@ -282,7 +284,11 @@ try:
             if changed:
                 updated += 1
     if added or updated:
-        with open(rpath, 'w') as f: json.dump(user, f, indent=2)
+        fd, tmp = tempfile.mkstemp(dir=os.path.dirname(rpath), suffix='.tmp')
+        with os.fdopen(fd, 'w') as f:
+            json.dump(user, f, indent=2)
+            f.write('\n')
+        os.replace(tmp, rpath)
         parts = []
         if added: parts.append(str(added) + ' new')
         if updated: parts.append(str(updated) + ' updated')
@@ -346,14 +352,14 @@ if [ -d "$SCRIPT_DIR/hooks/lib" ]; then
 fi
 
 # Step 8b: Install git pre-push hook (version+changelog enforcement)
-# v3.21.1 fix: use --absolute-git-dir; previous --git-dir returned a relative
-# `.git` when invoked from outside the repo, breaking `cp` (resolved against CWD).
-if git -C "$SCRIPT_DIR" rev-parse --absolute-git-dir >/dev/null 2>&1; then
-    GIT_HOOKS_DIR="$(git -C "$SCRIPT_DIR" rev-parse --absolute-git-dir 2>/dev/null)/hooks"
-    if [ -f "$SCRIPT_DIR/githooks/pre-push" ] && [ -d "$GIT_HOOKS_DIR" ]; then
-        cp "$SCRIPT_DIR/githooks/pre-push" "$GIT_HOOKS_DIR/pre-push"
-        chmod +x "$GIT_HOOKS_DIR/pre-push"
-        print_ok "Git pre-push hook installed (version+changelog guard)"
+if [ -d "$SCRIPT_DIR/.git" ]; then
+    GIT_HOOKS_DIR="$SCRIPT_DIR/.git/hooks"
+    if [ -f "$SCRIPT_DIR/.githooks/pre-push" ] && [ -d "$GIT_HOOKS_DIR" ]; then
+        if cp "$SCRIPT_DIR/.githooks/pre-push" "$GIT_HOOKS_DIR/pre-push" && chmod +x "$GIT_HOOKS_DIR/pre-push"; then
+            print_ok "Git pre-push hook installed (version+changelog guard)"
+        else
+            print_warn "Could not install git pre-push hook; continuing"
+        fi
     fi
 fi
 
@@ -479,13 +485,16 @@ cortex_hooks = {
 existing_hooks = settings.get("hooks", {})
 for event, handlers in cortex_hooks.items():
     existing = existing_hooks.get(event, [])
-    cleaned = [
-        h for h in existing
-        if not any(
-            "hooks/cortex/" in str(hook.get("command", ""))
-            for hook in h.get("hooks", [])
-        )
-    ]
+    cleaned = []
+    for h in existing:
+        kept_hooks = [
+            hook for hook in h.get("hooks", [])
+            if "hooks/cortex/" not in str(hook.get("command", ""))
+        ]
+        if kept_hooks:
+            h = dict(h)
+            h["hooks"] = kept_hooks
+            cleaned.append(h)
     existing_hooks[event] = cleaned + handlers
 
 settings["hooks"] = existing_hooks
@@ -522,46 +531,80 @@ fi
 print_step "Updating CLAUDE.md..."
 if [ -f "$CLAUDE_MD" ]; then
     # Backup CLAUDE.md before any modification
-    cp "$CLAUDE_MD" "${CLAUDE_MD}.backup.$(date +%Y%m%d-%H%M%S)" 2>/dev/null || true
+    cp "$CLAUDE_MD" "${CLAUDE_MD}.backup.$(date +%Y%m%d-%H%M%S)" 2>/dev/null || print_warn "Could not back up CLAUDE.md; continuing"
 
     if grep -q "## Cortex" "$CLAUDE_MD" 2>/dev/null; then
         # UPGRADE: replace existing Cortex section with latest
         if [ -n "$PYTHON_CMD" ]; then
-            "$PYTHON_CMD" -c '
+            if "$PYTHON_CMD" -c '
 import re, sys, os, tempfile
 claude_md = os.path.expanduser("~/.claude/CLAUDE.md")
 section_file = sys.argv[1]
-with open(claude_md) as f:
+with open(claude_md, encoding="utf-8") as f:
     content = f.read()
-with open(section_file) as f:
+with open(section_file, encoding="utf-8") as f:
     new_section = f.read()
-# Remove old section (from ## Cortex to next ## or EOF)
-content = re.sub(
-    r"\n*## Cortex \(Learning System\)\n.*?(?=\n## |\Z)",
-    "",
-    content,
-    flags=re.DOTALL
-)
-# Append new section
-content = content.rstrip() + "\n\n" + new_section + "\n"
-fd, tmp = tempfile.mkstemp(dir=os.path.dirname(claude_md), suffix=".tmp")
-with os.fdopen(fd, "w") as f:
-    f.write(content)
-os.replace(tmp, claude_md)
-' "$SCRIPT_DIR/core/claudemd-section.md" 2>/dev/null
-            print_ok "Cortex section updated in CLAUDE.md"
+
+header = re.search(r"(?m)^## Cortex \(Learning System\)\s*\n", content)
+warn = None
+if header:
+    start = header.start()
+    rest = content[start:]
+    marker = re.search(r"(?m)^<!-- cortex:end -->\s*$", rest)
+    legacy = re.search(r"### Laws inject automatically[^\n]*\n?", rest, flags=re.DOTALL)
+    if marker:
+        end = start + marker.end()
+    elif legacy:
+        end = start + legacy.end()
+    else:
+        next_heading = re.search(r"\n## ", content[header.end():])
+        if next_heading:
+            end = header.end() + next_heading.start()
+        else:
+            end = None
+            warn = "Cortex section boundary not found; manual cleanup may be needed"
+    if end is not None:
+        if start > 0 and content[start - 1] == "\n":
+            start -= 1
+        content = content[:start].rstrip() + "\n\n" + new_section.rstrip() + "\n" + content[end:].lstrip("\n")
+else:
+    content = content.rstrip() + "\n\n" + new_section.rstrip() + "\n"
+if warn:
+    print("WARN:" + warn, file=sys.stderr)
+else:
+    content = content.rstrip() + "\n"
+    fd, tmp = tempfile.mkstemp(dir=os.path.dirname(claude_md), suffix=".tmp")
+    with os.fdopen(fd, "w", encoding="utf-8") as f:
+        f.write(content)
+    os.replace(tmp, claude_md)
+' "$SCRIPT_DIR/core/claudemd-section.md" 2>"$CORTEX_DIR/.claudemd-update.err"; then
+                if grep -q "WARN:" "$CORTEX_DIR/.claudemd-update.err" 2>/dev/null; then
+                    print_warn "$(sed 's/^WARN://' "$CORTEX_DIR/.claudemd-update.err" | head -n1)"
+                else
+                    print_ok "Cortex section updated in CLAUDE.md"
+                fi
+                rm -f "$CORTEX_DIR/.claudemd-update.err"
+            else
+                print_error "Failed to update Cortex section in CLAUDE.md; continuing"
+                rm -f "$CORTEX_DIR/.claudemd-update.err"
+            fi
         else
             print_warn "Cortex section exists but Python not available to update it"
         fi
     else
         # FRESH: append
-        echo "" >> "$CLAUDE_MD"
-        cat "$SCRIPT_DIR/core/claudemd-section.md" >> "$CLAUDE_MD"
-        print_ok "Cortex section appended to CLAUDE.md"
+        if { printf '\n' >> "$CLAUDE_MD" && cat "$SCRIPT_DIR/core/claudemd-section.md" >> "$CLAUDE_MD"; }; then
+            print_ok "Cortex section appended to CLAUDE.md"
+        else
+            print_error "Failed to append Cortex section to CLAUDE.md; continuing"
+        fi
     fi
 else
-    cp "$SCRIPT_DIR/core/claudemd-section.md" "$CLAUDE_MD"
-    print_ok "Created CLAUDE.md with Cortex section"
+    if cp "$SCRIPT_DIR/core/claudemd-section.md" "$CLAUDE_MD"; then
+        print_ok "Created CLAUDE.md with Cortex section"
+    else
+        print_error "Failed to create CLAUDE.md with Cortex section; continuing"
+    fi
 fi
 
 # Step 12: Import backup (if provided)
@@ -645,6 +688,43 @@ os.replace(tmp, mem_path)
     fi
 fi
 
+# v4 adapter: seed the learner baseline on v3 upgrades so SessionStart does
+# not report lifetime observations as new work after the first v4 run.
+if [ "$HAS_CORTEX" = true ]; then
+    NEED_LEARN_BASELINE=false
+    if [ "$INSTALLED_VERSION" = "none" ] || version_lt "$INSTALLED_VERSION" "4.0.0"; then
+        NEED_LEARN_BASELINE=true
+    elif [ ! -f "$CORTEX_DIR/.last-learn-count" ] && find "$CORTEX_DIR/projects" -mindepth 2 -maxdepth 2 -name observations.jsonl -print -quit 2>/dev/null | grep -q .; then
+        NEED_LEARN_BASELINE=true
+    fi
+    if [ "$NEED_LEARN_BASELINE" = true ]; then
+        if "$PYTHON_CMD" - "$CORTEX_DIR" <<'PYEOF'; then
+import os, sys, tempfile
+root = sys.argv[1]
+projects = os.path.join(root, "projects")
+total = 0
+if os.path.isdir(projects):
+    for dirpath, _, filenames in os.walk(projects):
+        if "observations.jsonl" in filenames:
+            path = os.path.join(dirpath, "observations.jsonl")
+            try:
+                with open(path, "rb") as f:
+                    total += sum(1 for _ in f)
+            except OSError:
+                pass
+dest = os.path.join(root, ".last-learn-count")
+fd, tmp = tempfile.mkstemp(dir=root, suffix=".tmp")
+with os.fdopen(fd, "w", encoding="utf-8") as f:
+    f.write(str(total) + "\n")
+os.replace(tmp, dest)
+PYEOF
+            print_ok "Seeded learner observation baseline"
+        else
+            print_warn "Could not seed learner observation baseline"
+        fi
+    fi
+fi
+
 # Step 14: Write version marker + repo path (anti-drift guard, v3.34.1)
 echo "$NEW_VERSION" > "$CORTEX_DIR/version"
 # Record where this repo lives so SessionStart's check_deploy_drift() can warn
diff --git a/tests/test_install.sh b/tests/test_install.sh
index 15d59d7..c2ab8d1 100755
--- a/tests/test_install.sh
+++ b/tests/test_install.sh
@@ -204,6 +204,80 @@ CORTEX_COUNT=$(grep -c "## Cortex" "$SANDBOX/.claude/CLAUDE.md" 2>/dev/null)
 rm -rf "$SANDBOX"
 echo ""
 
+# ── TEST 3b: CLAUDE.md tail after Cortex section survives rerun ───
+
+echo "--- CLAUDE.md Tail Preservation ---"
+SANDBOX=$(mktemp -d)
+SANDBOXES+=("$SANDBOX")
+mkdir -p "$SANDBOX/.claude"
+printf '\n' | HOME="$SANDBOX" bash "$PROJECT_ROOT/install.sh" > /dev/null 2>&1 || true
+printf '\nUSER TAIL CONTENT\n' >> "$SANDBOX/.claude/CLAUDE.md"
+TAIL_BEFORE=$(tail -n 1 "$SANDBOX/.claude/CLAUDE.md")
+printf '\n' | HOME="$SANDBOX" bash "$PROJECT_ROOT/install.sh" > /dev/null 2>&1 || true
+TAIL_AFTER=$(tail -n 1 "$SANDBOX/.claude/CLAUDE.md")
+[ "$TAIL_AFTER" = "$TAIL_BEFORE" ] && [ "$TAIL_AFTER" = "USER TAIL CONTENT" ] && pass "CLAUDE.md user tail survives rerun" || fail "CLAUDE.md user tail changed"
+grep -q "<!-- cortex:end -->" "$SANDBOX/.claude/CLAUDE.md" 2>/dev/null && pass "CLAUDE.md Cortex section has end marker" || fail "CLAUDE.md missing end marker"
+rm -rf "$SANDBOX"
+echo ""
+
+# ── TEST 3c: settings.json keeps user hook sharing Cortex entry ───
+
+echo "--- settings.json Shared Entry Preservation ---"
+SANDBOX=$(mktemp -d)
+SANDBOXES+=("$SANDBOX")
+mkdir -p "$SANDBOX/.claude/cortex" "$SANDBOX/.claude/hooks/cortex"
+echo "3.37.2" > "$SANDBOX/.claude/cortex/version"
+cat > "$SANDBOX/.claude/settings.json" << 'JSON'
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {"type": "command", "command": "python3 ~/.claude/hooks/cortex/session-start.py"},
+          {"type": "command", "command": "bash ~/.claude/hooks/user-session-start.sh"}
+        ]
+      }
+    ]
+  }
+}
+JSON
+printf 'y\n' | HOME="$SANDBOX" bash "$PROJECT_ROOT/install.sh" > /dev/null 2>&1 || true
+python3 -c "
+import json
+with open('$SANDBOX/.claude/settings.json') as f:
+    s = json.load(f)
+hooks = [h for entry in s.get('hooks', {}).get('SessionStart', []) for h in entry.get('hooks', [])]
+assert any('user-session-start' in h.get('command', '') for h in hooks), 'user hook lost'
+print('OK')
+" 2>/dev/null | grep -q OK && pass "user hook preserved inside shared SessionStart entry" || fail "user hook lost from shared SessionStart entry"
+rm -rf "$SANDBOX"
+echo ""
+
+# ── TEST 3d: v3→v4 learner baseline seeded from observations ─────
+
+echo "--- v3 Learner Baseline Adapter ---"
+SANDBOX=$(mktemp -d)
+SANDBOXES+=("$SANDBOX")
+mkdir -p "$SANDBOX/.claude/cortex/projects/x" "$SANDBOX/.claude/hooks/cortex"
+echo "3.37.2" > "$SANDBOX/.claude/cortex/version"
+for i in 1 2 3 4 5; do echo "{\"n\":$i}"; done > "$SANDBOX/.claude/cortex/projects/x/observations.jsonl"
+printf 'y\n' | HOME="$SANDBOX" bash "$PROJECT_ROOT/install.sh" > /dev/null 2>&1 || true
+BASELINE=$(cat "$SANDBOX/.claude/cortex/.last-learn-count" 2>/dev/null | tr -d '[:space:]')
+[ "$BASELINE" = "5" ] && pass "v3 upgrade seeds .last-learn-count from observations" || fail ".last-learn-count=$BASELINE (expected 5)"
+rm -rf "$SANDBOX"
+echo ""
+
+# ── TEST 3e: interrupted install repair warning ───────────────────
+
+echo "--- Interrupted Install Repair Detection ---"
+SANDBOX=$(mktemp -d)
+SANDBOXES+=("$SANDBOX")
+mkdir -p "$SANDBOX/.claude/cortex/laws" "$SANDBOX/.claude/cortex/instincts/global" "$SANDBOX/.claude/hooks/cortex"
+OUT=$(printf 'y\n' | HOME="$SANDBOX" bash "$PROJECT_ROOT/install.sh" 2>&1 || true)
+printf '%s' "$OUT" | grep -q "proceeding as repair" && pass "missing version with hooks warns repair" || fail "repair warning missing"
+rm -rf "$SANDBOX"
+echo ""
+
 # ── TEST 4: Path traversal protection ─────────────────────────────
 
 echo "--- Path Traversal Protection ---"
diff --git a/tests/test_install_ps1.ps1 b/tests/test_install_ps1.ps1
index c4580fe..6fb5f04 100644
--- a/tests/test_install_ps1.ps1
+++ b/tests/test_install_ps1.ps1
@@ -254,6 +254,72 @@ if ($evalMissing -eq 0) {
     Test-Pass "evaluator.* propagation present (parity with install.sh)"
 }
 
+# ── TEST 11: v4.5 installer reliability contracts ────────────────
+
+Write-Host "--- v4.5 installer reliability contracts ---"
+$contractMissing = 0
+
+if ($content -match 'f"\{python_cmd\} ~/.claude/hooks/cortex/session-start.py"' -and
+    $content -notmatch '"command": "python3 ~/.claude/hooks/cortex/') {
+    Test-Pass "settings hook strings use detected Python interpreter"
+}
+else {
+    Test-Fail "settings hook strings still hardcode python3"
+    $contractMissing++
+}
+
+if (('../evil' -match '(^/|\.\.)') -and ('/abs' -match '(^/|\.\.)') -and -not ('safe/path' -match '(^/|\.\.)')) {
+    Test-Pass "path traversal regex matches ../ and absolute paths only"
+}
+else {
+    Test-Fail "path traversal regex behavior is wrong"
+    $contractMissing++
+}
+
+if ($content -match '\.repo-path') {
+    Test-Pass ".repo-path write present"
+}
+else {
+    Test-Fail ".repo-path write missing"
+    $contractMissing++
+}
+
+if ($content -match "encoding=['""]utf-8['""]" -and $content -match '-Encoding UTF8') {
+    Test-Pass "CLAUDE.md/Python reads and writes use UTF-8"
+}
+else {
+    Test-Fail "UTF-8 encoding contract missing"
+    $contractMissing++
+}
+
+if ($content -match '<!-- cortex:end -->' -and $content -match '### Laws inject automatically') {
+    Test-Pass "CLAUDE.md marker and legacy anchor present"
+}
+else {
+    Test-Fail "CLAUDE.md marker or legacy anchor missing"
+    $contractMissing++
+}
+
+if ($content -match 'Copy-Item \$memSrc \$memDest -Force' -and
+    $content -match 'Copy-Item \$refSrc \$refDest -Force' -and
+    $content -match 'if \(-not \(Test-Path \$regDest\)\) \{ Copy-Item \$regSrc \$regDest \}' -and
+    $content -match 'Copy-Item \$_.FullName \$dest -Recurse' -and
+    $content -match 'if \(-not \(Test-Path \$dest\)\) \{ Copy-Item \$_.FullName \$dest \}') {
+    Test-Pass "backup import overwrite/no-clobber semantics present"
+}
+else {
+    Test-Fail "backup import overwrite/no-clobber semantics incomplete"
+    $contractMissing++
+}
+
+if ($content -match '\.githooks", "pre-push"' -and $content -notmatch '[^.]githooks", "pre-push"') {
+    Test-Pass ".githooks/pre-push source used"
+}
+else {
+    Test-Fail ".githooks/pre-push source contract missing"
+    $contractMissing++
+}
+
 # ── Summary ───────────────────────────────────────────────────────
 
 Write-Host ""