feat: Publish-Remote Gate und die Anleitung fuer eine private Instanz (2.2.0)

Files changed:
- .gitignore
- AGENTS.md
- CHANGES.md
- VERSION
- instructions/gates.md
- instructions/private-instance.md
- tools/chemenu/commands/doctor.py
- tools/chemenu/commands/git_publish.py
- tools/chemenu/config.py
- tools/chemenu/tests/test_git_publish.py

.gitignore

@@ -110,6 +110,13 @@ npm-debug.log*
 # `dist export`; this anchored pattern deliberately does not match it.
 /ENVIRONMENT.md
 
+# Publish-Remote Gate allowlist (see instructions/gates.md). Names the push
+# URLs *this* checkout may publish to, so it is per-checkout for exactly the
+# reason ENVIRONMENT.md above is: a committed copy would tell a private clone
+# that the public upstream is a legitimate target for its own content. Absent
+# means unrestricted; `doctor` reports which.
+/.wikitool-remotes.json
+
 # Coverage output from `pytest --cov` (see .gitea/workflows/ci.yml). Derived,
 # like reports/: recomputable from any commit, and `publish` runs `git add -A`,
 # so an unignored htmlcov/ would commit itself on the next content publish.

AGENTS.md

@@ -20,7 +20,9 @@ tools/wikitool instructions sync
 Full procedure, including the tool environment: [instructions/bootstrap.md](instructions/bootstrap.md).
 Setting up a brand-new, empty instance instead of cloning this one: `tools/wikitool dist export`
 and [instructions/setup-instance.md](instructions/setup-instance.md) - see
-[INSTALL.md](INSTALL.md).
+[INSTALL.md](INSTALL.md). A *private* instance that keeps taking stack updates from a public
+upstream is a third shape, with a safeguard the other two do not need:
+[instructions/private-instance.md](instructions/private-instance.md).
 
 ## Invariants
 
@@ -177,16 +179,19 @@ tools/wikitool search --field entity_type=system --field 'confidence<0.6'
 
 ## Gates
 
-Two limits are enforced in code rather than by instruction, because a prompt-level limit is
+Three limits are enforced in code rather than by instruction, because a prompt-level limit is
 one an agent can talk itself past.
 
 - **Mass-Update Gate.** `publish` exits **42** on a change touching too many files, printing
   the file list and the `--confirm <token>` line that publishes it once the user approves. The
   threshold and the rule live in [instructions/gates.md](instructions/gates.md).
+- **Publish-Remote Gate.** `publish` exits **42** on a push to a URL this checkout has not
+  declared in `.wikitool-remotes.json`. It has no token and no flag: the way past it is a
+  deliberate edit by the user, never by an agent.
 - **Iteration Budget Gate / Loop-Breaker.** Past 60 `wikitool` calls in a session, or after 3
   identical calls in a row, further calls are refused.
 
-Both refuse with exit 1. **Do not retry, and do not open the gate.** Stop, summarize the
+The last refuses with exit 1. **Do not retry, and do not open a gate.** Stop, summarize the
 situation to the user, and get explicit approval. The full procedure - including why
 `budget reset` is not the escape hatch - is [instructions/gates.md](instructions/gates.md).
 

CHANGES.md

@@ -20,6 +20,62 @@ their date-only headings.
 
 ---
 
+## 2.2.0 - 2026-09-01 - Publish-Remote Gate: publish schreibt nur an erklaerte Ziele
+
+**Author:** Torben Nehmer
+
+Der Stack bekommt sein drittes Gate. Die beiden bestehenden fragen, ob eine Änderung zu groß
+ist und ob ein Rebase gefährlich ist. Dieses fragt, was darunter liegt: **ob das überhaupt das
+richtige Repository ist.**
+
+**Das Problem entsteht erst durch die private Instanz.** Ein Checkout mit eigenem Inhalt hat
+typischerweise zwei Remotes — sein eigenes und das öffentliche Upstream, von dem er
+Stack-Updates zieht. Git unterscheidet die beim Push nicht, also legt ein falsches `--remote`
+einen privaten Korpus auf ein öffentliches Repository. Das ist nicht billig rückholbar, und
+zwar nachweislich: Beim Veröffentlichen dieses Repos blieb die gesamte alte History nach dem
+Force-Push per SHA abrufbar, bis auf dem Server die Reflogs verfielen und `git gc --prune=now`
+lief. Ein Force-Push bewegt den Branch, nicht die Objekte.
+
+**`.wikitool-remotes.json` nennt die erlaubten Push-URLs.** Nicht die Remote-*Namen*: Eine
+Namensliste ließe ein `publish` durch, dessen `origin` umgebogen wurde, und genau das ist der
+Fall, den das Gate fangen soll. Gelesen wird die `pushurl`, wenn der Remote eine setzt, denn
+dorthin schreibt `git push` tatsächlich.
+
+**Pro Checkout und gitignored**, aus demselben Grund wie `ENVIRONMENT.md`: Zwei Klone pushen an
+zwei verschiedene Orte, eine committete Kopie würde einem privaten Klon also mitteilen, das
+öffentliche Upstream sei ein legitimes Ziel für seinen eigenen Inhalt. **Fehlt die Datei, gilt
+keine Beschränkung** — ein Checkout mit einem Remote und ohne Privates hat nichts zu schützen,
+und eine Pflichtdatei würde aus einer Sicherung Papierkram machen. Eine *kaputte* Datei ist
+dagegen ein Fehler und kein „keine Beschränkung": Eine beschädigte Sicherung darf sich nicht
+wie eine abgeschaltete verhalten.
+
+**Kein Token, keine Flagge.** Die anderen beiden Gates lösen sich mit einem `--confirm <token>`,
+weil ihre Frage („ist diese Änderung richtig?") für genau ein Changeset beantwortbar ist. Dieses
+fragt „gehört dieser Inhalt in jenes Repository?", und das ist eine stehende Eigenschaft des
+Checkouts, kein Einzelfallurteil. Der Weg daran vorbei ist ein bewusster Edit des Nutzers.
+Ein Agent, der die Datei anfasst, um an einer Verweigerung vorbeizukommen, öffnet ein Gate aus
+eigenem Antrieb — Invariante 6.
+
+**`doctor` meldet den Zustand** statt ihn zu erzwingen: OK mit Anzahl der Ziele, OK bei
+Abwesenheit mit einem Remote, und WARN bei mehr als einem Remote ohne Allowlist — also genau in
+der Form, die eine private Instanz annimmt, sobald sie das Upstream hinzufügt.
+
+**Und die Prozedur, für die das Gate gebaut wurde.** `instructions/private-instance.md` (neu)
+beschreibt die dritte Instanz-Form neben „frisch aufsetzen" und „Repo klonen": eine private
+Arbeitsinstanz, die Stack-Updates von einem öffentlichen Upstream per `git merge` zieht und
+deren eigener Inhalt nie zurückwandert. Der Grund, warum das dem Tarball-Weg vorzuziehen ist,
+steht dort ausformuliert — `cp -r` hat keinen Drei-Wege-Merge und keine Konflikterkennung.
+Schritt 4 der Anleitung ist das Gate, und zwar ausdrücklich **vor** dem ersten `publish`:
+später hinzugefügt schützt es das Fenster nicht, das es schließen soll.
+
+**Dateien:** `config.PUBLISH_REMOTES_FILENAME`, `git_publish.read_allowed_push_urls()`,
+`push_url_for()`, `publish_remote_refusal()` und die Prüfung vor dem Reconcile-Schritt,
+`doctor.check_publish_remotes()`, `.gitignore`, `instructions/gates.md`,
+`instructions/private-instance.md` (neu), `AGENTS.md` (Gate-Liste und Bootstrap-Routing),
+12 neue Tests in `test_git_publish.py`.
+
+---
+
 ## 2.1.1 - 2026-09-01 - raw_dir-Fixture kappt config.ROOT; letzte private Fixture-Namen ersetzt
 
 **Author:** Torben Nehmer
@@ -47,7 +103,7 @@ Nachgewiesen, indem `raw/documents/` lokal entfernt und die Suite erneut gefahre
 Provenance-Tests grün ohne das Verzeichnis, vorher rot.
 
 **Fixture-Namen.** Die Suite benutzte weiterhin reale Systemnamen der Ursprungsinstanz als
-Fixture-Bezeichner (`atlantis`, `abydos`, `Nathan`, `hermes`, `ecodms`, `Opa Hasso`). In einem
+Fixture-Bezeichner. In einem
 öffentlichen Repo beschreiben sie nichts, verraten aber die Namensgebung einer privaten
 Umgebung. Ersetzt durch `aurora`, `almanac`, `Borealis`, `gateway`, `docstore`. `gdeploy`
 bleibt: die Seite existiert im öffentlichen Korpus.

VERSION

@@ -1 +1 @@
-2.1.1
+2.2.0

instructions/gates.md

@@ -22,10 +22,11 @@ Read the exit code first - it says which of these applies:
 ## Exit 42: user clearance required
 
 A `wikitool` command that exits **42** is not reporting an error. It is refusing to act until a
-human has *read its output*. Two gates use it today - the Mass-Update Gate (`publish`, on a
+human has *read its output*. Three gates use it today - the Mass-Update Gate (`publish`, on a
-change touching 10 or more counted files) and the rebase-review gate (`sync` and `publish`, on
+change touching 10 or more counted files), the rebase-review gate (`sync` and `publish`, on
-a rebase whose incoming commits touch a file this session is also changing) - but the rule is
+a rebase whose incoming commits touch a file this session is also changing), and the
-about the exit code, not the command:
+Publish-Remote Gate (`publish`, on a push to a target this checkout has not declared) - but the
+rule is about the exit code, not the command:
 
 > **Copy the command's output into your reply - the substance of it, not a description of it -
 > and stop.** Run no further commands in that turn.
@@ -62,6 +63,42 @@ clearance.
 
 Background: [[Mass-Update Gate]] (`kb/concepts/Mass-Update Gate.md`).
 
+### Publish-Remote Gate
+
+The Mass-Update Gate asks whether a change is too large to publish. This one asks the question
+underneath it: **whether this is the right repository to publish to at all.**
+
+A checkout that holds private content usually has two remotes - its own, and the public upstream
+it takes stack updates from. Git does not distinguish them at push time, so one wrong `--remote`
+puts a private corpus on a public repository. That is not cheaply reversible: a force-push moves
+the branch, but the objects stay fetchable by SHA until someone expires the server's reflogs and
+runs `git gc --prune=now` on the bare repo.
+
+`.wikitool-remotes.json` names the push URLs a checkout permits:
+
+```json
+{ "schema": 1, "allowed_push_urls": ["ssh://git@example.net:22/you/your-wiki.git"] }
+```
+
+It pins **URLs, not remote names** - a name-based list would wave through a `publish` whose
+`origin` had been repointed, which is the failure it exists to catch. It reads the remote's
+`pushurl` when one is set, because that is where `git push` actually writes.
+
+The file is per-checkout and gitignored, for the same reason `ENVIRONMENT.md` is: two clones push
+to two different places, so a committed copy would tell a private clone that the public upstream
+is a legitimate target for its own content. **Absent means unrestricted** - a single-remote
+checkout with nothing private in it has nothing to protect, and `doctor` reports which state a
+checkout is in, WARNing only when there is more than one remote and no allowlist. A malformed
+file is an error rather than "no restriction": a corrupted safeguard must not read as a disabled
+one.
+
+**This gate has no `--confirm` token, on purpose.** The other two clear with a token because the
+question they ask ("is this change right?") is one the agent can put to the user and the user can
+answer for that one changeset. This one asks "does this content belong to that repository?", which
+is a standing property of the checkout, not a per-push judgment. The way past it is for the user
+to add the URL to the file. **An agent must never edit `.wikitool-remotes.json` to get past a
+refusal** - that is opening a gate on your own initiative, which AGENTS.md invariant 6 forbids.
+
 ## Iteration Budget Gate and loop-breaker
 
 Every `wikitool` call is counted per session. Calls are refused past **60 in a session**, or

instructions/private-instance.md

@@ -0,0 +1,125 @@
+---
+type: types/instruction.md
+name: private-instance
+description: Set up a private working instance as a clone of a public upstream, so stack updates arrive by merge instead of by copying a tarball over the tree.
+---
+
+# Set up a private instance against a public upstream
+
+The distribution path in [setup-instance.md](setup-instance.md) builds an instance from a
+`dist export` tarball, with no git ancestry in common with the repo it came from. That is the
+right shape for someone who only ever *consumes* the stack.
+
+This is the other shape: a private instance that keeps taking stack changes from a public
+upstream, and whose own content must never travel back. It costs one safeguard to set up and
+saves the whole update procedure afterwards.
+
+**Read this before, not after, the first `publish`.** The gate in step 4 is the thing that makes
+the arrangement safe, and adding it later means the window it closes was open in between.
+
+## Why a clone rather than a tarball
+
+`INSTALL.md`'s "Eine Instanz aktualisieren" is `cp -r` as an upgrade strategy: copy `tools/`,
+`types/`, `instructions/`, `AGENTS.md`, `VERSION` over the existing tree. It has no three-way
+merge, so it cannot notice that the receiving instance changed a file, and it has no conflict
+surface, so nobody learns when upstream and local both touched the same one. It overwrites
+silently.
+
+A clone gets all of that from git. The private `main` deletes the upstream's demo corpus once;
+every later `git merge upstream/main` sees *deleted-in-ours, unmodified-in-theirs* and resolves
+without asking. Stack changes land as real merges, with real conflicts where they conflict.
+
+## Steps
+
+1. **Clone, and name the two remotes for what they are.**
+
+   ```bash
+   git clone <private-repo-url> my-wiki
+   cd my-wiki
+   git remote add upstream <public-repo-url>
+   ```
+
+   `origin` is yours and is the only thing you ever push to. `upstream` is where stack updates
+   come from and is fetch-only.
+
+2. **Make the fetch-only half fetch-only in git, too.**
+
+   ```bash
+   git remote set-url --push upstream no_push
+   ```
+
+   git refuses to push to a URL it cannot resolve. This is a convenience, not the safeguard -
+   step 4 is the safeguard.
+
+3. **Delete the upstream's demo corpus once, on your own `main`.**
+
+   Everything under `kb/` and `raw/` that came with the clone is the upstream's content, not
+   yours. Remove it with `wikitool rm --page` (never `rm -rf`: `rm` de-links each page from the
+   rest of the wiki, and a plain delete leaves dead wikilinks and broken citations behind), then
+   `index rebuild`, `sources rebuild-index`, `lint`.
+
+   This is a one-time cut. Afterwards the upstream corpus is frozen from your side, which is
+   what makes later merges content-free.
+
+4. **Arm the Publish-Remote Gate — before the first `publish`.**
+
+   ```bash
+   cat > .wikitool-remotes.json <<'EOF'
+   { "schema": 1, "allowed_push_urls": ["<your-private-push-url>"] }
+   EOF
+   ```
+
+   Use the URL `git remote get-url --push origin` prints, exactly. `publish` refuses with exit
+   42 for anything else, and there is no flag that opens it - see [gates.md](gates.md).
+
+   The file is gitignored, so it stays with this checkout and never travels to the upstream.
+   `wikitool doctor` reports whether the gate is armed, and WARNs at more than one remote
+   without it.
+
+5. **Take away the write credential, if you can.** A token or deploy key for `origin` only,
+   with no write access to the upstream, is the one control that holds even if everything above
+   is misconfigured. Belt and braces.
+
+6. **Personalize and bootstrap.** `USER.md`, `SOUL.md` and optionally `ENVIRONMENT.md` are
+   yours and unrelated to the upstream's - see the Personalization step of
+   [setup-instance.md](setup-instance.md), then [bootstrap.md](bootstrap.md) for the venv and
+   the skills.
+
+## Taking a stack update
+
+```bash
+git fetch upstream
+git merge upstream/main
+```
+
+Then, as after any stack change: `doctor`, `docs verify`, `instructions verify`, `migrate status`,
+`lint`. A `migrate status` with outstanding links means the update crossed a compatibility
+boundary - follow [migrate-corpus.md](migrate-corpus.md) before doing anything else.
+
+## Where stack development happens
+
+**In the public repo, not here.** That is not a preference; the stack is built that way. The
+development-only half of the instruction layer is pruned from a distribution one-way, with no
+command that reconstructs it, so an instance built this way has no tool-development mode to
+switch into in the first place.
+
+When a tool bug blocks real content work here - and it will - file the issue against the public
+repo (an MCP server or the web UI reaches it from any session; no shared history needed), fix it
+there where the tests, `docs verify` and CI's version gate live, and take the fix back with the
+merge above. Nothing is lost by the detour: the fix has to pass that CI either way.
+
+## Decision points
+
+- **Merge conflict in `kb/` or `raw/`?** Something changed the upstream's corpus after you cut
+  it. Resolve as "keep deleted" - your instance's content is yours, and the upstream's demo
+  corpus has no business in it.
+- **Conflict in `tools/`, `types/` or `instructions/`?** You changed the stack locally, which
+  step "Where stack development happens" says not to do. Take the upstream side and re-file the
+  change as an issue there.
+
+## Scope
+
+Not for a first instance with no upstream - that is [setup-instance.md](setup-instance.md). Not
+for a fresh clone of a repo you already own and develop in - that is
+[bootstrap.md](bootstrap.md). This is specifically the two-remote case, where the cost of a
+mistaken push is disclosure rather than inconvenience.

tools/chemenu/commands/doctor.py

@@ -21,7 +21,7 @@ import typer
 from rich.console import Console
 
 from chemenu import config, kb_collections, version as version_mod
-from chemenu.commands import instructions_cmd
+from chemenu.commands import git_publish, instructions_cmd
 from chemenu.commands._util import rel_path
 from chemenu.session import ENV_VAR as SESSION_ENV_VAR
 
@@ -242,6 +242,42 @@ def check_environment() -> Check:
     return Check("environment", "OK", f"{config.ENVIRONMENT_FILE} present and filled")
 
 
+def check_publish_remotes() -> Check:
+    """Whether the Publish-Remote Gate is armed in this checkout.
+
+    Absent is a legitimate state, not a fault: a checkout with a single remote
+    and nothing private in it has nothing to protect, and making the file
+    mandatory would turn a safeguard into paperwork. So this never FAILs - it
+    reports, the way `environment` does.
+
+    It does WARN for the case that actually bites: more than one remote
+    configured and no allowlist. That is the shape a private instance has after
+    it adds the public upstream, and it is exactly when a wrong `--remote`
+    stops being a typo and starts being a disclosure.
+    """
+    urls = git_publish.read_allowed_push_urls()
+    if urls is not None:
+        return Check(
+            "publish-remotes", "OK",
+            f"{len(urls)} allowed push target(s) in {config.PUBLISH_REMOTES_FILENAME}",
+        )
+    result = subprocess.run(
+        ["git", "remote"], cwd=config.ROOT, capture_output=True, text=True
+    )
+    remotes = [r for r in result.stdout.split() if r]
+    if len(remotes) > 1:
+        return Check(
+            "publish-remotes", "WARN",
+            f"{len(remotes)} remotes ({', '.join(remotes)}) and no publish allowlist",
+            f"Create {config.PUBLISH_REMOTES_FILENAME} naming the push URL this checkout "
+            "may publish to - see instructions/gates.md",
+        )
+    return Check(
+        "publish-remotes", "OK",
+        f"No {config.PUBLISH_REMOTES_FILENAME} (unrestricted; one remote configured)",
+    )
+
+
 def check_generated_files() -> Check:
     missing = [
         rel_path(path)
@@ -355,6 +391,7 @@ def run_doctor() -> list[Check]:
         check_structure(),
         check_personalization(),
         check_environment(),
+        check_publish_remotes(),
         check_generated_files(),
         check_session_id(),
     ]

tools/chemenu/commands/git_publish.py

@@ -80,6 +80,86 @@ def _run(args: list[str]) -> subprocess.CompletedProcess:
     return subprocess.run(args, cwd=config.ROOT, capture_output=True, text=True)
 
 
+# --- Publish-Remote Gate -----------------------------------------------------
+#
+# The Mass-Update Gate asks "is this too much to publish?". This one asks the
+# question underneath it: "is this the right place to publish to at all?".
+#
+# A checkout holding private content typically has two remotes - its own, and
+# the public upstream it takes stack updates from. Nothing in git distinguishes
+# them at push time, so a single wrong `--remote` puts a private corpus on a
+# public repository, where a force-push does not take it back: the objects stay
+# fetchable by SHA until someone expires the server's reflogs.
+#
+# Like the other two gates this refuses with exit 42 and has **no flag that
+# opens it**. The way past it is to name the URL in the file, which is an edit
+# the user makes deliberately rather than something an agent can decide mid-run.
+
+
+def read_allowed_push_urls() -> Optional[list[str]]:
+    """The URLs this checkout permits `publish` to push to, or None when the
+    file is absent (unrestricted - see config.PUBLISH_REMOTES_FILENAME)."""
+    path = config.ROOT / config.PUBLISH_REMOTES_FILENAME
+    if not path.is_file():
+        return None
+    try:
+        data = json.loads(path.read_text(encoding="utf-8"))
+    except (OSError, json.JSONDecodeError) as exc:
+        fail(
+            f"{config.PUBLISH_REMOTES_FILENAME} is unreadable ({exc}). It decides where "
+            "`publish` may push, so a broken one is not treated as 'no restriction' - "
+            "fix the file or delete it deliberately."
+        )
+        return None
+    urls = data.get("allowed_push_urls")
+    if not isinstance(urls, list) or not all(isinstance(u, str) for u in urls):
+        fail(
+            f"{config.PUBLISH_REMOTES_FILENAME} has no usable `allowed_push_urls` list of "
+            "strings. Expected: {\"schema\": 1, \"allowed_push_urls\": [\"<url>\"]}"
+        )
+        return None
+    return urls
+
+
+def push_url_for(remote: str) -> Optional[str]:
+    """The URL `git push <remote>` would actually write to - `pushurl` when the
+    remote sets one, otherwise its fetch URL. Reading the resolved value rather
+    than the name is the whole point: a repointed `origin` must not pass."""
+    result = _run(["git", "remote", "get-url", "--push", remote])
+    if result.returncode != 0:
+        return None
+    return result.stdout.strip() or None
+
+
+def publish_remote_refusal(remote: str, branch: str) -> Optional[str]:
+    """The gate's message when `remote` is not an allowed push target, else None."""
+    allowed = read_allowed_push_urls()
+    if allowed is None:
+        return None
+    url = push_url_for(remote)
+    if url is None:
+        return (
+            f"Publish-Remote Gate: '{remote}' resolves to no push URL, so this publish "
+            f"cannot be checked against {config.PUBLISH_REMOTES_FILENAME}. Nothing was "
+            "committed or pushed."
+        )
+    if url in allowed:
+        return None
+    listed = "\n".join(f"  - {u}" for u in allowed) or "  (the list is empty)"
+    return (
+        f"Publish-Remote Gate: this checkout does not allow publishing to '{remote}'.\n\n"
+        f"  would push to: {url}\n"
+        f"  allowed here:\n{listed}\n\n"
+        "Nothing was committed or pushed. This checkout holds content that belongs to it "
+        "alone, and a push to the wrong remote is not cheaply reversible - the objects stay "
+        "fetchable by SHA even after a force-push, until the server's reflogs are expired.\n\n"
+        "THE USER CANNOT SEE THIS OUTPUT. It went to your context, not to their screen.\n"
+        "Show them the two lines above and stop. There is no flag that opens this gate: if "
+        f"the target really is right, the user adds its URL to {config.PUBLISH_REMOTES_FILENAME} "
+        "themselves. Do not edit that file to get past this."
+    )
+
+
 def parse_porcelain_entries(stdout: str) -> list[tuple[str, str]]:
     """Parse `git status --porcelain -z` output into (status_code, path) pairs.
 
@@ -919,6 +999,26 @@ def publish_command(
     if push and checked_out != branch:
         fail(branch_mismatch_message(checked_out, branch))
 
+    # Before the reconcile below, which is the first thing that talks to the
+    # remote at all: a publish aimed at the wrong repository should not even
+    # fetch from it, and the refusal message promises that nothing was
+    # committed or pushed.
+    if push:
+        refusal = publish_remote_refusal(remote, branch)
+        if refusal:
+            emit(
+                "wikitool",
+                "gate.refused",
+                {
+                    "gate": "publish-remote",
+                    "reason": "remote-not-allowed",
+                    "remote": remote,
+                    "branch": branch,
+                    "url": push_url_for(remote),
+                },
+            )
+            needs_clearance(refusal)
+
     # Pull against the remote before anything else, to minimise the window in which this
     # publish could diverge from it - and, as a side effect, to finally publish a commit left
     # stranded by a previous push that failed (see `_local_ahead_of_remote` below). Skipped

tools/chemenu/config.py

@@ -70,6 +70,22 @@ ENVIRONMENT_TEMPLATE = f"{ENVIRONMENT_FILE}.template"
 # `dist export` already computes (AGENTS.md invariant 8). See NOTICE.
 LICENSE_FILES = ("LICENSE", "LICENSE-CONTENT", "NOTICE")
 
+# Which push targets `publish` may write to, for a checkout that says so. The
+# danger this addresses is one checkout's content reaching another checkout's
+# remote - a private instance pushing its own `kb/` to a public upstream, where
+# it cannot be taken back.
+#
+# It pins **URLs, not remote names**: a name-based list would pass a `publish`
+# whose `origin` had been repointed, which is the failure it exists to catch.
+#
+# Per-checkout and gitignored, like `ENVIRONMENT.md` and for the same reason:
+# two clones of this repo push to two different places, so a committed copy
+# would hand the second one an answer that is wrong rather than missing. Absent
+# means unrestricted - `doctor` reports it, and the Publish-Remote Gate simply
+# does not apply. A checkout that holds private content should have one; see
+# instructions/gates.md.
+PUBLISH_REMOTES_FILENAME = ".wikitool-remotes.json"
+
 
 def default_author() -> str | None:
     """The author to stamp a new source page with, per instance.

tools/chemenu/tests/test_git_publish.py

@@ -1,3 +1,4 @@
+import json
 import subprocess
 
 import pytest
@@ -905,3 +906,115 @@ def test_numstat_survives_a_non_ascii_filename(repo):
     change = next(c for c in collect_changes([]) if c.path == name)
     assert change.status == "modified"
     assert (change.added, change.removed) == (1, 2)
+
+
+# --- Publish-Remote Gate -----------------------------------------------------
+
+
+def _allowlist(root, *urls):
+    (root / config.PUBLISH_REMOTES_FILENAME).write_text(
+        json.dumps({"schema": 1, "allowed_push_urls": list(urls)}), encoding="utf-8"
+    )
+
+
+def test_no_allowlist_means_unrestricted(repo):
+    """Absence is a legitimate state: a checkout with nothing private in it
+    should not have to declare anything to publish at all."""
+    assert git_publish.read_allowed_push_urls() is None
+    assert git_publish.publish_remote_refusal("origin", "main") is None
+
+
+def test_allowed_url_passes_the_gate(repo):
+    _allowlist(repo, git_publish.push_url_for("origin"))
+    assert git_publish.publish_remote_refusal("origin", "main") is None
+
+
+def test_gate_refuses_a_remote_not_on_the_list(repo):
+    _git(repo, "remote", "add", "upstream", "https://example.com/public.git")
+    _allowlist(repo, git_publish.push_url_for("origin"))
+    refusal = git_publish.publish_remote_refusal("upstream", "main")
+    assert refusal is not None
+    assert "https://example.com/public.git" in refusal
+    assert "Nothing was committed or pushed" in refusal
+
+
+def test_gate_matches_the_url_not_the_remote_name(repo):
+    """A name-based list would pass a repointed `origin`, which is the failure
+    this gate exists to catch."""
+    _allowlist(repo, "ssh://git@example.com/only-this.git")
+    assert git_publish.publish_remote_refusal("origin", "main") is not None
+
+
+def test_gate_reads_pushurl_when_the_remote_sets_one(repo):
+    """`git push` writes to `pushurl` when present, so that is the value that
+    has to be checked - not the fetch URL beside it."""
+    _git(repo, "remote", "set-url", "--push", "origin", "https://example.com/elsewhere.git")
+    _allowlist(repo, "https://example.com/elsewhere.git")
+    assert git_publish.push_url_for("origin") == "https://example.com/elsewhere.git"
+    assert git_publish.publish_remote_refusal("origin", "main") is None
+
+
+def test_gate_refuses_when_the_fetch_url_is_listed_but_the_pushurl_is_not(repo):
+    fetch_url = git_publish.push_url_for("origin")
+    _git(repo, "remote", "set-url", "--push", "origin", "https://example.com/elsewhere.git")
+    _allowlist(repo, fetch_url)
+    assert git_publish.publish_remote_refusal("origin", "main") is not None
+
+
+def test_publish_exits_42_and_commits_nothing_when_the_remote_is_refused(repo):
+    _git(repo, "remote", "add", "upstream", "https://example.com/public.git")
+    _allowlist(repo, git_publish.push_url_for("origin"))
+    before = _git(repo, "rev-parse", "HEAD").stdout.strip()
+    (repo / "kb" / "secret.md").write_text("private\n", encoding="utf-8")
+
+    with pytest.raises(typer.Exit) as excinfo:
+        _publish(remote="upstream")
+    assert excinfo.value.exit_code == EXIT_NEEDS_CLEARANCE
+
+    # Nothing committed, and the file is still sitting there unstaged - the
+    # refusal message promises both. (`git status --porcelain` collapses the
+    # wholly-untracked `kb/` to one entry, so check the index directly.)
+    assert _git(repo, "rev-parse", "HEAD").stdout.strip() == before
+    assert (repo / "kb" / "secret.md").exists()
+    assert "secret.md" not in _git(repo, "ls-files").stdout
+
+
+def test_no_push_skips_the_gate(repo):
+    """`--no-push` publishes nowhere, so there is no wrong target to protect
+    against - and a local commit must stay possible."""
+    _allowlist(repo, "ssh://git@example.com/only-this.git")
+    (repo / "kb" / "page.md").write_text("local\n", encoding="utf-8")
+    _publish(push=False)
+    assert "page.md" in _git(repo, "show", "--name-only", "HEAD").stdout
+
+
+def test_unreadable_allowlist_fails_instead_of_falling_open(repo):
+    """A broken file must not be read as 'no restriction' - that would turn a
+    corrupted safeguard into a silently disabled one."""
+    (repo / config.PUBLISH_REMOTES_FILENAME).write_text("{not json", encoding="utf-8")
+    with pytest.raises(typer.Exit):
+        git_publish.read_allowed_push_urls()
+
+
+def test_allowlist_without_a_usable_list_fails(repo):
+    (repo / config.PUBLISH_REMOTES_FILENAME).write_text(
+        json.dumps({"schema": 1, "allowed_push_urls": "not-a-list"}), encoding="utf-8"
+    )
+    with pytest.raises(typer.Exit):
+        git_publish.read_allowed_push_urls()
+
+
+def test_empty_allowlist_refuses_everything(repo):
+    """An empty list is a deliberate 'publish nowhere', not an oversight that
+    should behave like an absent file."""
+    _allowlist(repo)
+    assert git_publish.publish_remote_refusal("origin", "main") is not None
+
+
+def test_gate_has_no_flag_that_opens_it(repo):
+    """The other two gates clear with a token; this one deliberately does not,
+    because the right fix is a deliberate edit by the user."""
+    import inspect
+
+    params = inspect.signature(publish_command).parameters
+    assert not any("remote" in name and "confirm" in name for name in params)