diff --git a/lib/hook-utils.test.sh b/lib/hook-utils.test.sh
index c1786c5946..46cf4bea67 100755
--- a/lib/hook-utils.test.sh
+++ b/lib/hook-utils.test.sh
@@ -7,6 +7,10 @@
 
 set -uo pipefail
 
+# Fixture git isolation: an inherited GIT_DIR/GIT_WORK_TREE/GIT_CONFIG would
+# redirect `git init` / `git config` into the caller's repository.
+unset GIT_DIR GIT_WORK_TREE GIT_CONFIG
+
 HOOK_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
 PASS=0
diff --git a/plugins/claude-memory/.claude-plugin/plugin.json b/plugins/claude-memory/.claude-plugin/plugin.json
index f75ed93fc2..29fcd9476d 100644
--- a/plugins/claude-memory/.claude-plugin/plugin.json
+++ b/plugins/claude-memory/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "claude-memory",
-  "version": "0.11.1",
+  "version": "0.11.2",
   "description": "Keeps a repo's Claude Code memory layer healthy and under your control, against criteria derived from official Claude Code documentation. The audit skill checks the instruction/memory layer (CLAUDE.md, CLAUDE.local.md, .claude/rules/, auto-memory) with a deterministic script-backed spine plus judgment-tier checks. The stateless skill inspects, disables, and (confirm-gated) purges Claude-written auto memory across all settings scopes.",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/claude-memory/CHANGELOG.md b/plugins/claude-memory/CHANGELOG.md
index 28861bf13a..7cbe17a30e 100644
--- a/plugins/claude-memory/CHANGELOG.md
+++ b/plugins/claude-memory/CHANGELOG.md
@@ -3,6 +3,15 @@
 All notable changes to the `claude-memory` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.11.2]
+
+### Fixed
+
+- **Fixture isolation now clears `GIT_CONFIG` (#2889).** The audit and
+  stateless suite helpers already unset the discovery variables; they now
+  also unset `GIT_CONFIG`, the second leak path that replaces the file
+  `git config` reads and writes. Test-only; no skill behavior change.
+
 ## [0.11.1]
 
 ### Changed
diff --git a/plugins/claude-memory/skills/audit/scripts/memory-dir-stats.test.sh b/plugins/claude-memory/skills/audit/scripts/memory-dir-stats.test.sh
index a44c0a6391..55651e3d36 100755
--- a/plugins/claude-memory/skills/audit/scripts/memory-dir-stats.test.sh
+++ b/plugins/claude-memory/skills/audit/scripts/memory-dir-stats.test.sh
@@ -35,7 +35,7 @@ assert_contains() {
 
 # Fixture git repos must never inherit an outer hook chain's exported git env.
 make_repo() {
-  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR
+  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR GIT_CONFIG
   mkdir -p "$1"
   (cd "$1" && git init -q && git config user.email "test@example.com" && git config user.name "test" && git commit -q --allow-empty -m init)
 }
diff --git a/plugins/claude-memory/skills/audit/scripts/memory-index-refs-check.test.sh b/plugins/claude-memory/skills/audit/scripts/memory-index-refs-check.test.sh
index 417b8fb112..e08af0f58f 100755
--- a/plugins/claude-memory/skills/audit/scripts/memory-index-refs-check.test.sh
+++ b/plugins/claude-memory/skills/audit/scripts/memory-index-refs-check.test.sh
@@ -41,7 +41,7 @@ assert_not_contains() {
 
 # Fixture git repos must never inherit an outer hook chain's exported git env.
 make_repo() {
-  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR
+  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR GIT_CONFIG
   mkdir -p "$1"
   (cd "$1" && git init -q && git config user.email "test@example.com" && git config user.name "test" && git commit -q --allow-empty -m init)
 }
diff --git a/plugins/claude-memory/skills/audit/scripts/orphan-rule-check.test.sh b/plugins/claude-memory/skills/audit/scripts/orphan-rule-check.test.sh
index b5e8e647ba..caa8afecbd 100755
--- a/plugins/claude-memory/skills/audit/scripts/orphan-rule-check.test.sh
+++ b/plugins/claude-memory/skills/audit/scripts/orphan-rule-check.test.sh
@@ -42,7 +42,7 @@ assert_not_contains() {
 # Fixture git repos must never inherit an outer hook chain's exported git env —
 # otherwise fixture commits mutate the REAL repo.
 make_repo() {
-  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR
+  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR GIT_CONFIG
   mkdir -p "$1"
   (cd "$1" && git init -q && git config user.email "test@example.com" && git config user.name "test" && git commit -q --allow-empty -m init)
 }
diff --git a/plugins/claude-memory/skills/stateless/scripts/scope-report.test.sh b/plugins/claude-memory/skills/stateless/scripts/scope-report.test.sh
index d6276f6988..090ce66d12 100755
--- a/plugins/claude-memory/skills/stateless/scripts/scope-report.test.sh
+++ b/plugins/claude-memory/skills/stateless/scripts/scope-report.test.sh
@@ -32,7 +32,7 @@ assert_contains() {
 
 # Fixture git repos must never inherit an outer hook chain's exported git env.
 make_repo() {
-  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR
+  unset GIT_DIR GIT_INDEX_FILE GIT_WORK_TREE GIT_COMMON_DIR GIT_CONFIG
   mkdir -p "$1"
   (cd "$1" && git init -q && git config user.email "test@example.com" && git config user.name "test" && git commit -q --allow-empty -m init)
 }
diff --git a/plugins/repo-hygiene/.claude-plugin/plugin.json b/plugins/repo-hygiene/.claude-plugin/plugin.json
index 177f16a6f4..46c6435ae5 100644
--- a/plugins/repo-hygiene/.claude-plugin/plugin.json
+++ b/plugins/repo-hygiene/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "repo-hygiene",
-  "version": "0.10.7",
+  "version": "0.10.8",
   "description": "Repo hygiene action-router: /repo-hygiene:clean sweeps reclaimable caches, build artifacts, and stale git metadata, and can realign the working tree to a fresh-pull state \u2014 dry-run-first, with destructive tiers gated behind explicit confirmation and a session-scoped destructive-command guard. Ecosystem targets are detected at runtime; secrets, runtime dependencies, and skill data are preserved by default.",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/repo-hygiene/CHANGELOG.md b/plugins/repo-hygiene/CHANGELOG.md
index a591945137..be951a846d 100644
--- a/plugins/repo-hygiene/CHANGELOG.md
+++ b/plugins/repo-hygiene/CHANGELOG.md
@@ -3,6 +3,14 @@
 All notable changes to the `repo-hygiene` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.10.8]
+
+### Fixed
+
+- **Fixture isolation now clears `GIT_CONFIG` (#2889).** The shared clean
+  test helper already unset the discovery variables at source time; it now
+  also unsets `GIT_CONFIG`. Test-only; no skill behavior change.
+
 ## [0.10.7]
 
 ### Changed
diff --git a/plugins/repo-hygiene/skills/clean/scripts/lib/test-helpers.sh b/plugins/repo-hygiene/skills/clean/scripts/lib/test-helpers.sh
index e94fda9bc5..495562c0a3 100644
--- a/plugins/repo-hygiene/skills/clean/scripts/lib/test-helpers.sh
+++ b/plugins/repo-hygiene/skills/clean/scripts/lib/test-helpers.sh
@@ -17,7 +17,7 @@ readonly _CLEAN_TEST_HELPERS_LOADED=1
 # Strip inherited git-hook context so a fixture `git init` in these tests
 # resolves to the mktemp fixture, never the real repo (a git-hook chain exports
 # GIT_DIR / GIT_INDEX_FILE etc.).
-unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_OBJECT_DIRECTORY
+unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_OBJECT_DIRECTORY GIT_CONFIG
 
 : "${FAILED:=0}"
 : "${CASE_NUM:=0}"
diff --git a/plugins/skill-quality/.claude-plugin/plugin.json b/plugins/skill-quality/.claude-plugin/plugin.json
index 639c293dc8..94d4535c5d 100644
--- a/plugins/skill-quality/.claude-plugin/plugin.json
+++ b/plugins/skill-quality/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "skill-quality",
-  "version": "0.17.3",
+  "version": "0.17.4",
   "description": "Skill-authoring QA tooling: a static contract checker that runs twenty-four deterministic checks over a Claude Code skill (frontmatter, explicit invocation mode, per-skill listing-entry cap, trigger-keyword preservation, line caps, broken internal refs, markdownlint, gotchas surface, evals presence, precompute opportunity, completion-criteria signal, injection shell-declaration, fresh-eyes declaration conformance), a shared skill-listing budget reporter across a set of skills, and a bundled evals.json schema plus a deterministic eval-quality lint (duplicate case identities, missing fixtures, empty or vague grading criteria, set-coverage warnings). Runs against any repo's skills directory via the convention-resolution ladder \u2014 no baked layout.",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/skill-quality/CHANGELOG.md b/plugins/skill-quality/CHANGELOG.md
index c8b6778d59..7bf42f823a 100644
--- a/plugins/skill-quality/CHANGELOG.md
+++ b/plugins/skill-quality/CHANGELOG.md
@@ -3,6 +3,14 @@
 All notable changes to the `skill-quality` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.17.4]
+
+### Fixed
+
+- **Fixture isolation now clears `GIT_CONFIG` (#2889).** `check-skill` and
+  `check-listing-budget` suites already unset the discovery variables; they
+  now also unset `GIT_CONFIG`. Test-only; no skill behavior change.
+
 ## [0.17.3]
 
 ### Changed
diff --git a/plugins/skill-quality/scripts/check-listing-budget.test.sh b/plugins/skill-quality/scripts/check-listing-budget.test.sh
index a95255daec..3a7cea2f01 100755
--- a/plugins/skill-quality/scripts/check-listing-budget.test.sh
+++ b/plugins/skill-quality/scripts/check-listing-budget.test.sh
@@ -19,7 +19,7 @@ TMP="$(mktemp -d)"
 trap 'rm -rf "$TMP"' EXIT
 
 export GIT_CONFIG_GLOBAL=/dev/null GIT_CONFIG_SYSTEM=/dev/null
-unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX 2>/dev/null || true
+unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_CONFIG 2>/dev/null || true
 git -C "$TMP" init -q
 git -C "$TMP" config user.email test@example.com
 git -C "$TMP" config user.name test
diff --git a/plugins/skill-quality/scripts/check-skill.test.sh b/plugins/skill-quality/scripts/check-skill.test.sh
index c0b2bf95c6..c10ba64ac5 100755
--- a/plugins/skill-quality/scripts/check-skill.test.sh
+++ b/plugins/skill-quality/scripts/check-skill.test.sh
@@ -24,7 +24,7 @@ trap 'rm -rf "$TMP"' EXIT
 
 # Fresh repo, isolated from any ambient git-hook env that would leak into it.
 export GIT_CONFIG_GLOBAL=/dev/null GIT_CONFIG_SYSTEM=/dev/null
-unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX 2>/dev/null || true
+unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_CONFIG 2>/dev/null || true
 git -C "$TMP" init -q
 git -C "$TMP" config user.email test@example.com
 git -C "$TMP" config user.name test
diff --git a/plugins/source-control/.claude-plugin/plugin.json b/plugins/source-control/.claude-plugin/plugin.json
index df46b46478..554b518cfa 100644
--- a/plugins/source-control/.claude-plugin/plugin.json
+++ b/plugins/source-control/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "source-control",
-  "version": "0.54.14",
+  "version": "0.54.15",
   "description": "Git and GitHub delivery workflow: /commit (Conventional Commits + Co-authored-by trailer via safe heredoc mechanics), /pull-request (prep, create, CI monitoring, review-comment triage, merge, CI-log fetch), /babysit-prs (self-pacing fleet loop \u2014 safe by default; opt-in worker/autopilot tiers add gate-checked merge and thread resolution behind a deterministic Python engine), /babysit-loop (the loop-lane merge lane: a standing or drain loop that invokes babysit-prs per cycle, configured through repo-scoped babysit_loop_* keys on the layered source-control.md seam, with merge authority human-only until the target repo's tracked config adopts the lane, a gate-proven C2-mechanical baseline once adopted, and standing merge-rung raises binding from the team-tracked layer only \u2014 with one named exception, where an invocation line explicitly typing both the autopilot tier keyword and the dedicated raise argument --merge c3-this-run widens that single invocation's merge authority up to C3 behind a fresh independent frontier-tier resolver, while C4-structural and C5-untrusted-provenance stay unconditionally human-merge), /worktree (create, status, cleanup, audit for parallel-session isolation), /setup (check the effective commit-subject / PR-title convention merged across its config layers and the babysit-prs config, or apply \u2014 interview the repo and write the convention config to a chosen layer), and /resolve-conflicts (intent-first merge/rebase conflict resolution with a semantic-conflict sweep \u2014 never --abort). The commit-subject / PR-title convention is configurable via a source-control.md config written by a re-runnable setup skill, layered across a ~/.claude user-global file, the tracked team file, and a gitignored .claude/source-control.local.md personal overlay merged per key; Conventional Commits is the default when no convention is declared.",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/source-control/CHANGELOG.md b/plugins/source-control/CHANGELOG.md
index a34144eaac..b9ebd4f7fd 100644
--- a/plugins/source-control/CHANGELOG.md
+++ b/plugins/source-control/CHANGELOG.md
@@ -3,6 +3,14 @@
 All notable changes to the `source-control` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.54.15]
+
+### Fixed
+
+- **Fixture isolation now clears `GIT_CONFIG` (#2889).** The plugin test
+  helper already unset the discovery variables at source time; it now also
+  unsets `GIT_CONFIG`. Test-only; no skill behavior change.
+
 ## [0.54.14]
 
 ### Changed
diff --git a/plugins/source-control/scripts/test-helpers.sh b/plugins/source-control/scripts/test-helpers.sh
index 9500fcbe12..8a67b0c71c 100644
--- a/plugins/source-control/scripts/test-helpers.sh
+++ b/plugins/source-control/scripts/test-helpers.sh
@@ -18,7 +18,7 @@ readonly _TESTS_LIB_LOADED=1
 
 # Strip inherited git-hook context so fixture `git init` / ref writes never
 # resolve to the real repo when a test runs under a git hook chain.
-unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_OBJECT_DIRECTORY
+unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_OBJECT_DIRECTORY GIT_CONFIG
 
 : "${FAILED:=0}"
 : "${CASE_NUM:=0}"
diff --git a/plugins/work-items/.claude-plugin/plugin.json b/plugins/work-items/.claude-plugin/plugin.json
index ed5d80484c..591a19a576 100644
--- a/plugins/work-items/.claude-plugin/plugin.json
+++ b/plugins/work-items/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "work-items",
-  "version": "0.39.10",
+  "version": "0.39.11",
   "description": "Manages development work items through a provider-neutral tracker seam that ships with the plugin (bundled dispatcher plus github, local-markdown, jira, gitea, and linear adapters; seam plugin-dir canonical, adapters consumer-local-first): dashboard, taxonomy-labeled creation, a race-safe assignee-plus-lease claim protocol, recurring-schedule checks, TODO scanning, stale-lease auditing, plan decomposition into vertical-slice items, a macro-journey router over spec containers (rollup, per-container execution shape, next-step routing), raw-intake triage (issues and unsolicited PRs through raw, verified, briefed, autonomous-eligible states), plus the two work-items loop lanes of the loop-lane convention: a self-paced autonomous work-loop drain (work-class admission gate, adaptive item cap, PR-only) and an attended attend-queue escalation lane. The re-runnable setup skill binds the provider (.work-item-tracker.json), seeds the recurring-schedule seam (.github/recurring-schedule.json), and remaps canonical role labels.",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/work-items/CHANGELOG.md b/plugins/work-items/CHANGELOG.md
index 26086446ac..393f90f2f4 100644
--- a/plugins/work-items/CHANGELOG.md
+++ b/plugins/work-items/CHANGELOG.md
@@ -3,6 +3,14 @@
 All notable changes to the `work-items` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.39.11]
+
+### Fixed
+
+- **Fixture isolation now clears `GIT_CONFIG` (#2889).** The tracker test
+  harness already unset the discovery variables at source time; it now also
+  unsets `GIT_CONFIG`. Test-only; no skill behavior change.
+
 ## [0.39.10]
 
 ### Added
diff --git a/plugins/work-items/tools/work-item-tracker/tests/lib.sh b/plugins/work-items/tools/work-item-tracker/tests/lib.sh
index b2ea6a8aa5..46046b0b78 100644
--- a/plugins/work-items/tools/work-item-tracker/tests/lib.sh
+++ b/plugins/work-items/tools/work-item-tracker/tests/lib.sh
@@ -25,7 +25,7 @@ readonly _WIT_TESTS_LIB_LOADED=1
 # never resolve to the real repo instead of its throwaway dir (a git hook chain
 # exports GIT_DIR / GIT_INDEX_FILE etc.; leaving them set has rewritten a real
 # repo's refs in the past). Every seam test gets a clean git environment.
-unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_OBJECT_DIRECTORY
+unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_COMMON_DIR GIT_PREFIX GIT_OBJECT_DIRECTORY GIT_CONFIG
 
 # Defensive counter defaults so the first assertion in a test that forgot to
 # declare them does not trip `set -u`.
diff --git a/scripts/check-fixture-git-isolation.sh b/scripts/check-fixture-git-isolation.sh
index 22c4e0dce8..a6038c0fbc 100755
--- a/scripts/check-fixture-git-isolation.sh
+++ b/scripts/check-fixture-git-isolation.sh
@@ -37,14 +37,13 @@
 #
 #     unset GIT_DIR GIT_WORK_TREE GIT_CONFIG
 #
-# GIT_CONFIG belongs in every clear list and the harnesses here all carry it: it
+# GIT_CONFIG belongs in every clear list and the CREDIT signal requires it: it
 # is a SECOND leak path, not another spelling of the first, because it replaces
 # the file the `git config` subcommand reads and writes rather than redirecting
-# discovery, so it survives `-C` and a cleared GIT_DIR alike. The CREDIT signal
-# below is deliberately narrower than the recommended list — GIT_DIR plus
-# GIT_WORK_TREE — because widening it would retroactively re-violate every suite
-# in the corpus that already clears correctly for the discovery path. Widening
-# it is tracked in #2889 rather than smuggled in here.
+# discovery, so it survives `-C` and a cleared GIT_DIR alike. Official docs
+# (git-config ENVIRONMENT): if no `--file` is given, `GIT_CONFIG` is used as
+# if it were `--file`. That is why a suite that only unsets the discovery
+# pair is still exposed.
 #
 # or if it sources a harness that does — scripts/test-git-helpers.sh is the
 # repo's shared one. Sourced harnesses are resolved by BASENAME against the
@@ -64,8 +63,11 @@
 #         os.environ.pop(_leaked_git_var, None)
 #
 # Because that idiom spans lines, the Python check is FILE-scoped rather than
-# line-scoped: the file must perform an environ pop/delete AND name both
-# load-bearing variables. Python has no `source` equivalent here, so a Python
+# line-scoped: the file must perform an environ pop/delete AND name every
+# load-bearing variable (GIT_DIR, GIT_WORK_TREE, GIT_CONFIG). A module-level
+# name bound to a literal of those names, then iterated into the pop, is the
+# same clear — the loop-variable tie follows that binding, not only an
+# in-header literal. Python has no `source` equivalent here, so a Python
 # suite must carry its own clear; there is no harness-inheritance path to
 # resolve, and that is recorded as a deliberate limit rather than an oversight.
 #
@@ -110,10 +112,17 @@ esac
 # every classification below is ONE bulk awk pass over the whole tracked set
 # rather than a grep per file. Three passes total, not eleven hundred.
 #
-# CLEARS: a shell file that unsets both load-bearing variables on one line, or
-#   a Python file that pops/deletes them from os.environ and names both. The
-#   Python arm is FILE-scoped because the idiom spans lines (a tuple of names
-#   iterated into os.environ.pop), so its verdict is emitted at end-of-file.
+# CLEARS: a shell file that unsets every load-bearing variable (GIT_DIR,
+#   GIT_WORK_TREE, GIT_CONFIG) on one logical line via `unset` (process-wide),
+#   or that wraps EVERY fixture command with `env -u`/`--unset` naming each
+#   (per-command; one wrap does not isolate a later unwrapped write), or a
+#   Python file that pops/deletes them from os.environ and names all three.
+#   The Python arm is FILE-scoped because the idiom spans lines (a tuple of
+#   names iterated into os.environ.pop), so its verdict is emitted at
+#   end-of-file. The shell arm joins physical lines while the previous line
+#   ends in an unescaped backslash, so a continued `git … \` / `unset … \`
+#   is one unit (the same recall the Python arm already had for
+#   formatter-wrapped argv).
 # FIXTURE: a suite that runs a repository-creating or identity-writing git
 #   command. Comments are stripped first, so prose about `git init` in a header
 #   does not conscript a suite that never touches a fixture. The command form is
@@ -138,8 +147,9 @@ scan() {
       OPEN  = "[[({]"
       CLOSE = "[]})]"
       # The variables a clear must name to earn credit, shared by both arms so
-      # the two languages cannot drift apart.
-      NREQ = 2; REQ[1] = "GIT_DIR"; REQ[2] = "GIT_WORK_TREE"
+      # the two languages cannot drift apart. GIT_CONFIG is the third because
+      # it is a distinct leak path (git-config ENVIRONMENT: used as --file).
+      NREQ = 3; REQ[1] = "GIT_DIR"; REQ[2] = "GIT_WORK_TREE"; REQ[3] = "GIT_CONFIG"
       # A joined Python logical line is capped. An unbalanced bracket inside a
       # string literal would otherwise accumulate to end of file, and a runaway
       # join is unsafe for CLEARS specifically: it could sweep an unrelated
@@ -218,8 +228,25 @@ scan() {
              s ~ ("del[ \t]+os[ \t]*\\.[ \t]*environ[ \t]*\\[[ \t]*" v "[ \t]*\\]")
     }
 
-    function py_logical(s,   i, v) {
+    function py_logical(s,   i, v, hdr, cname) {
       if (is_fixture(s)) print "FIXTURE\t" FILENAME
+      # A module-level name bound to a literal of the required names is the
+      # other spelling of the in-header tuple. Credit still requires a later
+      # loop over THAT name to perform the pop — a constant that merely
+      # mentions the names, or a pop that never met the constant, cannot
+      # satisfy the tie.
+      # Any assignment to a name drops its previous CONST binding. Only a
+      # list/tuple literal then re-populates it — `LEAKED = get_names()`
+      # must not keep the names an earlier literal left behind.
+      if (match(s, /^[ \t]*[A-Za-z_][A-Za-z0-9_]*[ \t]*=/)) {
+        cname = substr(s, RSTART, RLENGTH)
+        sub(/^[ \t]+/, "", cname)
+        sub(/[ \t]*=.*/, "", cname)
+        for (i = 1; i <= NREQ; i++) delete CONST[cname, REQ[i]]
+        if (s ~ /^[ \t]*[A-Za-z_][A-Za-z0-9_]*[ \t]*=[ \t]*[[(]/)
+          for (i = 1; i <= NREQ; i++)
+            if (s ~ (Q REQ[i] Q)) CONST[cname, REQ[i]] = 1
+      }
       if (match(s, /for[ \t]+[A-Za-z_][A-Za-z0-9_]*[ \t]+in[ \t]*[[(]/)) {
         v = substr(s, RSTART, RLENGTH)
         sub(/^for[ \t]+/, "", v)
@@ -232,6 +259,20 @@ scan() {
         for (i = 1; i <= NREQ; i++) delete BOUND[v, REQ[i]]
         for (i = 1; i <= NREQ; i++)
           if (s ~ (Q REQ[i] Q)) BOUND[v, REQ[i]] = 1
+      } else if (match(s, /for[ \t]+[A-Za-z_][A-Za-z0-9_]*[ \t]+in[ \t]+[A-Za-z_][A-Za-z0-9_]*/)) {
+        # `for _v in LEAKED:` — the iterable is a name, not a literal. Copy
+        # whatever that name currently binds; a rebound constant has already
+        # cleared CONST above.
+        hdr = substr(s, RSTART, RLENGTH)
+        v = hdr
+        sub(/^for[ \t]+/, "", v)
+        sub(/[ \t]+in[ \t]+.*/, "", v)
+        cname = hdr
+        sub(/^for[ \t]+[A-Za-z_][A-Za-z0-9_]*[ \t]+in[ \t]+/, "", cname)
+        LOOPVAR[v] = 1
+        for (i = 1; i <= NREQ; i++) delete BOUND[v, REQ[i]]
+        for (i = 1; i <= NREQ; i++)
+          if (CONST[cname, REQ[i]]) BOUND[v, REQ[i]] = 1
       }
       for (i = 1; i <= NREQ; i++)
         if (pops_literal(s, REQ[i])) CLEARED[REQ[i]] = 1
@@ -251,11 +292,91 @@ scan() {
       print "CLEARS\t" cur
     }
 
+    # A shell physical line continues when the comment-stripped text, trimmed,
+    # ends in an unescaped backslash. `\\` at end of line is an escaped
+    # backslash, not a continuation; an odd trailing run is a continuation.
+    function is_cont(s,   t) {
+      t = s
+      sub(/[ \t]+$/, "", t)
+      return t ~ /(^|[^\\])(\\\\)*\\$/
+    }
+
+    # `env -u NAME` / `env --unset NAME` / `env --unset=NAME` is a correct
+    # per-command clear. Credit requires the clearing call itself to name
+    # every required variable, matching the unset-statement rule: a later
+    # mention on the same line cannot grant it, and naming only the discovery
+    # pair is not enough.
+    function env_clears(s,   i, ok) {
+      if (s !~ /(^|[ \t;|&])env[ \t]/) return 0
+      for (i = 1; i <= NREQ; i++) {
+        ok = (s ~ ("-u[ \t]*" REQ[i] "([^A-Za-z0-9_]|$)") ||
+              s ~ ("--unset=" REQ[i] "([^A-Za-z0-9_]|$)") ||
+              s ~ ("--unset[ \t]+" REQ[i] "([^A-Za-z0-9_]|$)"))
+        if (!ok) return 0
+      }
+      return 1
+    }
+
+    function unset_clears(s,   u, i) {
+      if (s !~ /^[ \t]*unset[ \t]/) return 0
+      u = s
+      sub(/^[ \t]*unset[ \t]+/, "", u)
+      sub(/;.*/, "", u)
+      for (i = 1; i <= NREQ; i++)
+        if (u !~ ("(^|[^A-Za-z0-9_])" REQ[i] "([^A-Za-z0-9_]|$)")) return 0
+      return 1
+    }
+
+    function sh_logical(s,   rest, path, fixture, n, i, segs) {
+      # Score fixture / env-u / unset per STATEMENT, not per physical or
+      # backslash-joined line. `env -u … git init; git config user.email`
+      # is two commands: the wrap applies only to the first (GNU env:
+      # removals apply while it runs COMMAND). A file-wide name presence
+      # test on the joined string would credit the unwrapped write.
+      n = split(s, segs, /[ \t]*(\|\||&&|;)[ \t]*/)
+      for (i = 1; i <= n; i++) {
+        fixture = is_fixture(segs[i])
+        if (fixture) print "FIXTURE\t" FILENAME
+        # `unset` is process-wide, so one statement isolates every later
+        # command in the file. `env -u` is per-COMMAND, so a wrap on one
+        # fixture statement must not credit a later unwrapped identity
+        # write. Credit env-only when every fixture statement is itself
+        # an env clear.
+        if (unset_clears(segs[i])) SH_UNSET = 1
+        if (env_clears(segs[i])) SH_ENV = 1
+        else if (fixture) SH_ENV_GAP = 1
+      }
+      if (s ~ /^[ \t]*(source|\.)[ \t]+/) {
+        rest = s
+        sub(/^[ \t]*(source|\.)[ \t]+/, "", rest)
+        # Take the first .sh-looking token rather than everything up to the
+        # first space: `. "$(dirname "$0")/lib/harness.sh"` embeds a space
+        # INSIDE the path expression, and truncating there loses the basename
+        # entirely — an under-selection, which is the unsafe direction here.
+        if (match(rest, /[^ \t"();|&]*\.sh/)) {
+          path = substr(rest, RSTART, RLENGTH)
+          sub(/.*\//, "", path)
+          if (path != "") print "SOURCE\t" FILENAME "\t" path
+        }
+      }
+    }
+
+    function sh_drain() {
+      if (sh_pending != "") { sh_logical(sh_pending); sh_pending = ""; sh_joined = 0 }
+    }
+
+    function sh_flush() {
+      sh_drain()
+      if (cur != "" && (SH_UNSET || (SH_ENV && !SH_ENV_GAP))) print "CLEARS\t" cur
+    }
+
     FILENAME != cur {
-      py_drain(); flush_py()
+      py_drain(); flush_py(); sh_flush()
       cur = FILENAME
-      split("", CLEARED); split("", BOUND); split("", LOOPVAR)
+      split("", CLEARED); split("", BOUND); split("", LOOPVAR); split("", CONST)
       pending = ""; depth = 0; joined = 0
+      sh_pending = ""; sh_joined = 0
+      SH_UNSET = 0; SH_ENV = 0; SH_ENV_GAP = 0
       ispy = (FILENAME ~ /\.py$/)
     }
     { line = $0; gsub(/\r/, "", line); code = line; sub(/#.*/, "", code) }
@@ -280,35 +401,19 @@ scan() {
       next
     }
 
-    # SHELL ARM.
+    # SHELL ARM. Same logical-line join as the Python arm, but the join
+    # signal is a trailing unescaped backslash rather than open brackets:
+    # `git -C "$d" \ init` and `unset GIT_DIR \ GIT_WORK_TREE \ GIT_CONFIG`
+    # are each one unit. A runaway join is capped at MAXJOIN.
     {
-      if (is_fixture(code)) print "FIXTURE\t" FILENAME
-      # Comments are already stripped, and the names are matched inside the
-      # `unset` STATEMENT rather than anywhere on the line, so neither prose nor
-      # a later command on the same line can grant the credit.
-      if (code ~ /^[ \t]*unset[ \t]/) {
-        u = code
-        sub(/^[ \t]*unset[ \t]+/, "", u)
-        sub(/;.*/, "", u)
-        if (u ~ /(^|[^A-Za-z0-9_])GIT_DIR([^A-Za-z0-9_]|$)/ &&
-            u ~ /(^|[^A-Za-z0-9_])GIT_WORK_TREE([^A-Za-z0-9_]|$)/)
-          print "CLEARS\t" FILENAME
-      }
-      if (code ~ /^[ \t]*(source|\.)[ \t]+/) {
-        rest = code
-        sub(/^[ \t]*(source|\.)[ \t]+/, "", rest)
-        # Take the first .sh-looking token rather than everything up to the
-        # first space: `. "$(dirname "$0")/lib/harness.sh"` embeds a space
-        # INSIDE the path expression, and truncating there loses the basename
-        # entirely — an under-selection, which is the unsafe direction here.
-        if (match(rest, /[^ \t"();|&]*\.sh/)) {
-          path = substr(rest, RSTART, RLENGTH)
-          sub(/.*\//, "", path)
-          if (path != "") print "SOURCE\t" FILENAME "\t" path
-        }
-      }
+      piece = code
+      cont = is_cont(code)
+      if (cont) sub(/[ \t]*\\[ \t]*$/, "", piece)
+      sh_pending = (sh_pending == "" ? piece : sh_pending " " piece)
+      sh_joined++
+      if (!cont || sh_joined >= MAXJOIN) sh_drain()
     }
-    END { py_drain(); flush_py() }
+    END { py_drain(); flush_py(); sh_flush() }
   ' "$@"
 }
 
diff --git a/scripts/check-fixture-git-isolation.test.sh b/scripts/check-fixture-git-isolation.test.sh
index b1a01fe2e4..6a4c2e7956 100755
--- a/scripts/check-fixture-git-isolation.test.sh
+++ b/scripts/check-fixture-git-isolation.test.sh
@@ -90,7 +90,7 @@ new_repo
 r="$REPO"
 cat >"$r/clean.test.sh" <<'SH'
 #!/usr/bin/env bash
-unset GIT_DIR GIT_WORK_TREE
+unset GIT_DIR GIT_WORK_TREE GIT_CONFIG
 d="$(mktemp -d)"
 git -C "$d" init -q
 git -C "$d" config user.email test@example.com
@@ -99,11 +99,33 @@ commit_all "$r"
 out="$(run_gate "$r")"
 rc=$?
 if [[ $rc -eq 0 ]]; then
-  ok "suite that unsets GIT_DIR/GIT_WORK_TREE passes"
+  ok "suite that unsets GIT_DIR/GIT_WORK_TREE/GIT_CONFIG passes"
 else
   fail "self-clearing suite: rc=$rc out='$out'"
 fi
 
+# --- clearing only the discovery pair is NOT enough (#2889) ------------------
+# GIT_CONFIG is a second leak path (git-config ENVIRONMENT: used as --file),
+# so a suite that only unsets GIT_DIR and GIT_WORK_TREE still writes through
+# an inherited GIT_CONFIG.
+new_repo
+r="$REPO"
+cat >"$r/no-config.test.sh" <<'SH'
+#!/usr/bin/env bash
+unset GIT_DIR GIT_WORK_TREE
+d="$(mktemp -d)"
+git -C "$d" init -q
+git -C "$d" config user.email test@example.com
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"no-config.test.sh"* ]]; then
+  ok "unsetting GIT_DIR/GIT_WORK_TREE without GIT_CONFIG is still a violation"
+else
+  fail "discovery-only clear: rc=$rc out='$out'"
+fi
+
 # --- clearing only GIT_DIR is NOT enough -------------------------------------
 new_repo
 r="$REPO"
@@ -129,7 +151,7 @@ r="$REPO"
 mkdir -p "$r/lib"
 cat >"$r/lib/harness.sh" <<'SH'
 # shellcheck shell=bash
-unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE
+unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_CONFIG
 SH
 cat >"$r/sourced.test.sh" <<'SH'
 #!/usr/bin/env bash
@@ -193,7 +215,7 @@ new_repo
 r="$REPO"
 cat >"$r/fixed.test.sh" <<'SH'
 #!/usr/bin/env bash
-unset GIT_DIR GIT_WORK_TREE
+unset GIT_DIR GIT_WORK_TREE GIT_CONFIG
 d="$(mktemp -d)"
 git -C "$d" init -q
 git -C "$d" config user.email test@example.com
@@ -385,7 +407,7 @@ new_repo
 r="$REPO"
 cat >"$r/test_clean.py" <<'PY'
 import os, subprocess
-for _v in ("GIT_DIR", "GIT_WORK_TREE", "GIT_INDEX_FILE"):
+for _v in ("GIT_DIR", "GIT_WORK_TREE", "GIT_INDEX_FILE", "GIT_CONFIG"):
     os.environ.pop(_v, None)
 def make(d):
     subprocess.run(["git", "init", "-q", d], check=True)
@@ -395,7 +417,7 @@ commit_all "$r"
 out="$(run_gate "$r")"
 rc=$?
 if [[ $rc -eq 0 ]]; then
-  ok "python: popping GIT_DIR and GIT_WORK_TREE passes"
+  ok "python: popping GIT_DIR, GIT_WORK_TREE and GIT_CONFIG passes"
 else
   fail "python cleared: rc=$rc out='$out'"
 fi
@@ -419,6 +441,26 @@ else
   fail "python half-cleared: rc=$rc out='$out'"
 fi
 
+# --- PYTHON: popping the discovery pair without GIT_CONFIG is NOT enough -----
+new_repo
+r="$REPO"
+cat >"$r/test_no_config.py" <<'PY'
+import os, subprocess
+for _v in ("GIT_DIR", "GIT_WORK_TREE"):
+    os.environ.pop(_v, None)
+def make(d):
+    subprocess.run(["git", "init", "-q", d], check=True)
+    subprocess.run(["git", "-C", d, "config", "user.email", "test@example.com"], check=True)
+PY
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"test_no_config.py"* ]]; then
+  ok "python: popping GIT_DIR/GIT_WORK_TREE without GIT_CONFIG is still a violation"
+else
+  fail "python discovery-only clear: rc=$rc out='$out'"
+fi
+
 # --- PYTHON: naming the variables without popping anything is NOT enough -----
 # Guards the fail-OPEN direction: a file that only mentions GIT_DIR in a comment
 # must not be credited with clearing it.
@@ -483,6 +525,7 @@ import subprocess
 for _leaked_git_var in (
     "GIT_DIR",
     "GIT_WORK_TREE",
+    "GIT_CONFIG",
 ):
     os.environ.pop(_leaked_git_var, None)
 
@@ -636,6 +679,233 @@ else
   fail "shell commented unset: rc=$rc out='$out'"
 fi
 
+# --- SHELL: a backslash-continued git command is still SEEN (#2893) ----------
+# A per-physical-line scan never has `git` and `init` on one line here, so the
+# suite would not merely get the wrong verdict — it would be invisible to the
+# gate. The Python arm already joined on open brackets; the shell arm now
+# joins while the previous line ends in an unescaped backslash.
+new_repo
+r="$REPO"
+cat >"$r/continued-init.test.sh" <<'SH'
+#!/usr/bin/env bash
+d="$(mktemp -d)"
+git -C "$d" \
+  init -q
+git -C "$d" \
+  config \
+  user.email t@t.test
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"continued-init.test.sh"* ]]; then
+  ok "shell: a backslash-continued git command is still detected as a fixture"
+else
+  fail "shell continued fixture: rc=$rc out='$out'"
+fi
+
+# --- SHELL: a backslash-continued unset of all three PASSES (#2893) ----------
+new_repo
+r="$REPO"
+cat >"$r/continued-unset.test.sh" <<'SH'
+#!/usr/bin/env bash
+unset GIT_DIR \
+      GIT_WORK_TREE \
+      GIT_CONFIG
+d="$(mktemp -d)"
+git -C "$d" init -q
+git -C "$d" config user.email test@example.com
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 0 ]]; then
+  ok "shell: a backslash-continued unset of all three required names passes"
+else
+  fail "shell continued unset: rc=$rc out='$out'"
+fi
+
+# --- SHELL: env -u naming all three is a clear (#2893) -----------------------
+# Use `$d` rather than `"$(mktemp -d)"` as the -C argument: the latter embeds a
+# space, and the fixture matcher (option-and-argument pairs) would then miss
+# `init` — the suite would not be a fixture at all, so both this case and the
+# half-clear below would "pass" for the wrong reason.
+new_repo
+r="$REPO"
+cat >"$r/env-unset.test.sh" <<'SH'
+#!/usr/bin/env bash
+d="$(mktemp -d)"
+env -u GIT_DIR -u GIT_WORK_TREE -u GIT_CONFIG git -C "$d" init -q
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 0 ]]; then
+  ok "shell: env -u naming GIT_DIR/GIT_WORK_TREE/GIT_CONFIG passes"
+else
+  fail "shell env -u clear: rc=$rc out='$out'"
+fi
+
+# --- SHELL: every fixture command wrapped with env -u PASSES -----------------
+new_repo
+r="$REPO"
+cat >"$r/env-all.test.sh" <<'SH'
+#!/usr/bin/env bash
+d="$(mktemp -d)"
+env -u GIT_DIR -u GIT_WORK_TREE -u GIT_CONFIG git -C "$d" init -q
+env -u GIT_DIR -u GIT_WORK_TREE -u GIT_CONFIG git -C "$d" config user.email test@example.com
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 0 ]]; then
+  ok "shell: env -u wrapping every fixture command passes"
+else
+  fail "shell env -u all wrapped: rc=$rc out='$out'"
+fi
+
+# --- SHELL: env -u on one fixture line does not credit an unwrapped write ----
+# env -u is per-COMMAND. A wrap on `init` must not isolate a later bare
+# `config user.email` — that is the leak the gate exists to stop.
+new_repo
+r="$REPO"
+cat >"$r/env-mixed.test.sh" <<'SH'
+#!/usr/bin/env bash
+d="$(mktemp -d)"
+env -u GIT_DIR -u GIT_WORK_TREE -u GIT_CONFIG git -C "$d" init -q
+git -C "$d" config user.email test@example.com
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"env-mixed.test.sh"* ]]; then
+  ok "shell: env -u on one command does not credit an unwrapped identity write"
+else
+  fail "shell env -u mixed: rc=$rc out='$out'"
+fi
+
+# --- SHELL: env -u and an unwrapped write on ONE `;` line is still a gap -----
+# The same leak as env-mixed, reached through one physical line. A
+# file-wide name-presence test on the joined string would credit it.
+new_repo
+r="$REPO"
+cat >"$r/env-semi.test.sh" <<'SH'
+#!/usr/bin/env bash
+d="$(mktemp -d)"
+env -u GIT_DIR -u GIT_WORK_TREE -u GIT_CONFIG git -C "$d" init -q; git -C "$d" config user.email test@example.com
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"env-semi.test.sh"* ]]; then
+  ok "shell: env -u and an unwrapped write on one semicolon line is still a violation"
+else
+  fail "shell env -u semicolon: rc=$rc out='$out'"
+fi
+
+# --- SHELL: env -u of the discovery pair without GIT_CONFIG is NOT enough ----
+new_repo
+r="$REPO"
+cat >"$r/env-half.test.sh" <<'SH'
+#!/usr/bin/env bash
+d="$(mktemp -d)"
+env -u GIT_DIR -u GIT_WORK_TREE git -C "$d" init -q
+SH
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"env-half.test.sh"* ]]; then
+  ok "shell: env -u without GIT_CONFIG is still a violation"
+else
+  fail "shell env -u discovery-only: rc=$rc out='$out'"
+fi
+
+# --- PYTHON: a module-level constant iterated into pop PASSES (#2893) --------
+new_repo
+r="$REPO"
+cat >"$r/test_const_clear.py" <<'PY'
+import os, subprocess
+LEAKED = ("GIT_DIR", "GIT_WORK_TREE", "GIT_CONFIG")
+for _v in LEAKED:
+    os.environ.pop(_v, None)
+def make(d):
+    subprocess.run(["git", "init", "-q", d], check=True)
+    subprocess.run(["git", "-C", d, "config", "user.email", "test@example.com"], check=True)
+PY
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 0 ]]; then
+  ok "python: a module-level constant iterated into pop passes"
+else
+  fail "python const clear: rc=$rc out='$out'"
+fi
+
+# --- PYTHON: a constant that only NAMES the vars does not credit -------------
+new_repo
+r="$REPO"
+cat >"$r/test_const_mention.py" <<'PY'
+import subprocess
+LEAKED = ("GIT_DIR", "GIT_WORK_TREE", "GIT_CONFIG")
+def make(d):
+    subprocess.run(["git", "init", "-q", d], check=True)
+    subprocess.run(["git", "-C", d, "config", "user.email", "test@example.com"], check=True)
+PY
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"test_const_mention.py"* ]]; then
+  ok "python: a constant naming the variables without popping is still a violation"
+else
+  fail "python const mention: rc=$rc out='$out'"
+fi
+
+# --- PYTHON: a REBOUND constant does not carry a stale binding ---------------
+new_repo
+r="$REPO"
+cat >"$r/test_const_rebound.py" <<'PY'
+import os, subprocess
+LEAKED = ("GIT_DIR", "GIT_WORK_TREE", "GIT_CONFIG")
+LEAKED = ("HOME",)
+for _v in LEAKED:
+    os.environ.pop(_v, None)
+def make(d):
+    subprocess.run(["git", "init", "-q", d], check=True)
+    subprocess.run(["git", "-C", d, "config", "user.email", "test@example.com"], check=True)
+PY
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"test_const_rebound.py"* ]]; then
+  ok "python: a rebound constant does not inherit an earlier binding"
+else
+  fail "python const rebound: rc=$rc out='$out'"
+fi
+
+# --- PYTHON: rebinding a constant to a CALL drops the earlier literal --------
+new_repo
+r="$REPO"
+cat >"$r/test_const_rebind_call.py" <<'PY'
+import os, subprocess
+def get_names():
+    return ("HOME",)
+LEAKED = ("GIT_DIR", "GIT_WORK_TREE", "GIT_CONFIG")
+LEAKED = get_names()
+for _v in LEAKED:
+    os.environ.pop(_v, None)
+def make(d):
+    subprocess.run(["git", "init", "-q", d], check=True)
+    subprocess.run(["git", "-C", d, "config", "user.email", "test@example.com"], check=True)
+PY
+commit_all "$r"
+out="$(run_gate "$r")"
+rc=$?
+if [[ $rc -eq 1 && "$out" == *"test_const_rebind_call.py"* ]]; then
+  ok "python: rebinding a constant to a call does not keep the earlier literal"
+else
+  fail "python const rebind-call: rc=$rc out='$out'"
+fi
+
 # --- SCOPE: a declared counter-fixture is exempt -----------------------------
 new_repo
 r="$REPO"
diff --git a/scripts/fixture-git-isolation-baseline.txt b/scripts/fixture-git-isolation-baseline.txt
index e977a9a458..8ff55a1382 100644
--- a/scripts/fixture-git-isolation-baseline.txt
+++ b/scripts/fixture-git-isolation-baseline.txt
@@ -12,7 +12,7 @@
 #
 # To clear an entry, add this once near the top of the suite:
 #
-#     unset GIT_DIR GIT_WORK_TREE
+#     unset GIT_DIR GIT_WORK_TREE GIT_CONFIG
 #
 # or source a harness that already does it (scripts/test-git-helpers.sh, or the
 # plugin-local *-test-helpers.sh siblings). Sourcing is preferred where the