diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 067d5321..ede947e2 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -24,6 +24,10 @@ on:
         description: "Version to pack+publish (e.g. 0.1.0-preview.1). Required to actually push on a manual run; omit for a pack-only dry run."
         type: string
         required: false
+      admission_only:
+        description: "Check registry collisions and OIDC authentication without packing or publishing; package creation scope is not exposed by NuGet. Ignores version-tag checkout."
+        type: boolean
+        default: false
       source_run_id:
         description: "Failed tag release run whose retained package artifact must be resumed."
         type: string
@@ -44,7 +48,7 @@ jobs:
     name: Verify (locked restore + headless build + test)
     runs-on: ubuntu-latest
     # Restrict to the canonical repo: fork tags/dispatch never run this (no fork secret exposure).
-    if: github.repository == 'FS-GG/FS.GG.Game' && (github.event_name != 'release' || startsWith(github.event.release.tag_name, 'v'))
+    if: github.repository == 'FS-GG/FS.GG.Game' && (github.event_name != 'release' || startsWith(github.event.release.tag_name, 'v')) && (github.event_name != 'workflow_dispatch' || inputs.admission_only != true)
     timeout-minutes: 20
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
@@ -60,6 +64,7 @@ jobs:
         run: |
           tests/release/test-game-0-17-release.sh --source-only
           tests/release/test-game-0-17-release-selftest.sh
+          python3 tests/release/test-release-admission.py
 
       # COLD, via the shared action (#135 / FS-GG/.github#429) — and this is the job where a warm
       # restore was worst. There is no `cache: true` here to blame: --locked-mode validates the
@@ -81,7 +86,7 @@ jobs:
   publish-packages:
     name: Publish FS.GG.Game.* (org feed + nuget.org, release-only)
     runs-on: ubuntu-latest
-    if: github.repository == 'FS-GG/FS.GG.Game' && (github.event_name != 'release' || startsWith(github.event.release.tag_name, 'v'))
+    if: github.repository == 'FS-GG/FS.GG.Game' && (github.event_name != 'release' || startsWith(github.event.release.tag_name, 'v')) && (github.event_name != 'workflow_dispatch' || inputs.admission_only != true)
     needs: [verify]
     permissions:
       actions: read
@@ -332,3 +337,43 @@ jobs:
           path: artifacts/readback.json
           if-no-files-found: error
           retention-days: 90
+
+  admission:
+    name: Observe registry and OIDC admission (no publication)
+    if: github.repository == 'FS-GG/FS.GG.Game' && github.event_name == 'workflow_dispatch' && inputs.admission_only == true
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: read
+      packages: write # Match the publisher principal; this job makes only registry GET requests.
+      id-token: write
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+      - name: Guard isolated observation mode
+        shell: bash
+        env:
+          SOURCE_RUN_ID: ${{ inputs.source_run_id }}
+        run: |
+          test -z "$SOURCE_RUN_ID"
+          python3 tests/release/test-release-admission.py
+      - name: Read both registries with the actual repository token
+        env:
+          FEED_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: python3 tests/release/observe-release-admission.py --registries artifacts/admission/registries.json
+      - name: Exchange workflow identity (no package push)
+        id: admission-login
+        uses: NuGet/login@8d196754b4036150537f80ac539e15c2f1028841 # v1
+        with:
+          user: ${{ secrets.NUGET_USER || 'Paradigma11' }}
+      - name: Verify predecessor package authority without publication
+        env:
+          NUGET_API_KEY: ${{ steps.admission-login.outputs.NUGET_API_KEY }}
+        run: python3 tests/release/observe-release-admission.py --authority artifacts/admission/authority.json
+      - name: Retain sanitized observations
+        if: always()
+        uses: actions/upload-artifact@v7
+        with:
+          name: game-release-admission-${{ github.sha }}-${{ github.run_id }}
+          path: artifacts/admission/*.json
+          if-no-files-found: warn
+          retention-days: 30
diff --git a/tests/release/RELEASE-ADMISSION.md b/tests/release/RELEASE-ADMISSION.md
new file mode 100644
index 00000000..f7ceb87b
--- /dev/null
+++ b/tests/release/RELEASE-ADMISSION.md
@@ -0,0 +1,54 @@
+# No-publication release observation
+
+The existing `release.yml` workflow accepts `admission_only=true` on manual
+dispatch. This runs a bounded five-minute observation job at the selected source
+ref and skips both the full release verifier and the publisher. It does not need
+a release tag, pack, restore, or package upload. Leave `source_run_id` empty.
+
+The job reads both registries using the actual repository workflow token, checks
+the known Core 0.16.0 predecessor to distinguish registry authentication from an
+unqualified 404, and refuses a visible 0.17.0 collision or unavailable response.
+Registry absence means absent to that principal; it does not prove permission
+to create a package or reveal unrelated private packages.
+
+It then uses the same pinned NuGet/login action and account selection as the
+publisher. This exchanges the workflow identity for a temporary credential; it
+is **not a credential-free dry run**. No credential is written into observations
+or printed by the observation script. The action masks its credential output.
+Authenticated GET `api/v2/verifykey/{id}` observations check existing package
+authority. Cross-host redirects strip credentials. Only sanitized status,
+source/run, time and limitation data become artifacts.
+
+A successful observation is deliberately limited. NuGet's exchange response
+contains token type, expiry and key, with no scope readback. Its verify-key route
+looks up a package before evaluating its scope; a missing adapter identity
+returns 404 without testing new-package creation permission. Therefore the report
+always marks adapter creation scope **not exposed and unproven**. It must not be
+interpreted as full publication authorization. The account policy roster is a
+sign-in-protected UI; the GitHub OIDC exchange does not authorize that UI read.
+
+These boundaries were checked against [NuGetGallery source at
+63b66c98287c61c7e00fe6aefaff86c0d73ba157](https://github.com/NuGet/NuGetGallery/tree/63b66c98287c61c7e00fe6aefaff86c0d73ba157):
+`TokenApiController.ApiKeyJson`, `ApiController.VerifyPackageKeyInternalAsync`,
+and `UsersController.TrustedPublishing`. [Current NuGet documentation](https://learn.microsoft.com/en-us/nuget/nuget-org/trusted-publishing)
+supports new packages through policy scopes and globs. Platform capability is
+distinct from the effective account's scope.
+
+This source change creates no mandatory manual approval or owner-policy-export
+gate. It provides a machine route to observe what the existing interfaces expose.
+It cannot create missing trust or credentials. The ordinary stable publication
+still uses GitHub-first, one retained coherent package set, OIDC public push,
+same-byte readbacks and authenticated retained-byte recovery. No release or
+successful provider observation is claimed by adding this route.
+
+Offline qualification:
+
+```sh
+python3 tests/release/test-release-admission.py
+tests/release/test-game-0-17-release.sh --source-only
+tests/release/test-game-0-17-release-selftest.sh
+```
+
+The offline controls cover visible collisions, unauthorized/unavailable registry
+responses, predecessor authentication, missing-identity scope limits, credential
+redirect stripping, and isolation from publication. They do not contact providers.
diff --git a/tests/release/observe-release-admission.py b/tests/release/observe-release-admission.py
new file mode 100644
index 00000000..823c4ada
--- /dev/null
+++ b/tests/release/observe-release-admission.py
@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+"""Bounded GET observations; no package or policy writes, no credential readbacks."""
+import argparse
+import base64
+from datetime import datetime, timezone
+import json
+import os
+from pathlib import Path
+import urllib.error
+import urllib.request
+from urllib.parse import urlsplit
+import xml.etree.ElementTree as ET
+
+PACKAGES = ("FS.GG.Game.Core", "FS.GG.Game.Render", "FS.GG.Game.Harness", "FS.GG.Game.Physics.Box2D")
+ROOT = Path(__file__).resolve().parents[2]
+
+
+class SafeRedirect(urllib.request.HTTPRedirectHandler):
+    def redirect_request(self, request, response, code, message, headers, newurl):
+        redirected = super().redirect_request(request, response, code, message, headers, newurl)
+        if redirected is not None and urlsplit(request.full_url).netloc != urlsplit(newurl).netloc:
+            redirected.remove_header("Authorization")
+            redirected.remove_header("X-nuget-apikey")
+        return redirected
+
+
+def observe(url, headers=None):
+    request = urllib.request.Request(url, headers={"User-Agent": "FS-GG-Game-release-admission/1", **(headers or {})}, method="GET")
+    try:
+        with urllib.request.build_opener(SafeRedirect()).open(request, timeout=15) as response:
+            # Discard response bodies. Credential-bearing endpoints never become artifacts.
+            return response.status
+    except urllib.error.HTTPError as error:
+        return error.code
+    except (urllib.error.URLError, TimeoutError):
+        return 0
+
+
+def collect(mode, version):
+    rows = []
+    if mode == "registries":
+        token = os.environ["FEED_TOKEN"]
+        authorization = "Basic " + base64.b64encode(("fs-gg:" + token).encode()).decode()
+        headers = {"Authorization": authorization}
+        sentinel = observe("https://nuget.pkg.github.com/FS-GG/download/fs.gg.game.core/0.16.0/fs.gg.game.core.0.16.0.nupkg", headers)
+        failed = sentinel != 200
+        for package in PACKAGES:
+            lower = package.lower()
+            for feed, prefix, auth in (
+                ("github", "https://nuget.pkg.github.com/FS-GG/download", headers),
+                ("nuget", "https://api.nuget.org/v3-flatcontainer", None),
+            ):
+                status = observe(f"{prefix}/{lower}/{version}/{lower}.{version}.nupkg", auth)
+                rows.append({"package": package, "feed": feed, "httpStatus": status,
+                             "observation": "absent-to-this-principal" if status == 404 else "collision" if status == 200 else "unknown"})
+                failed |= status != 404
+        return {"githubPredecessorReadHttpStatus": sentinel, "packages": rows,
+                "limits": "GET access does not prove new-package creation authority or visibility of unrelated private packages."}, failed
+    key = os.environ["NUGET_API_KEY"]
+    headers = {"X-NuGet-ApiKey": key}
+    failed = False
+    for package in PACKAGES:
+        # No version asks for the existing registration; a missing identity is 404 before scope evaluation.
+        status = observe(f"https://www.nuget.org/api/v2/verifykey/{package}", headers)
+        existing = package != "FS.GG.Game.Physics.Box2D"
+        rows.append({"package": package, "httpStatus": status,
+                     "authority": "existing-package-push" if status == 200 else "unproven"})
+        failed |= status != (200 if existing else 404)
+    return {"oidcExchange": "completed", "packages": rows,
+            "newAdapterCreationScope": "not-exposed-and-unproven",
+            "limits": "OIDC exchange returns no scopes. Verify-key 200 covers existing identity; missing identity 404 does not evaluate creation scope. This is not full publication authorization."}, failed
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    modes = parser.add_mutually_exclusive_group(required=True)
+    modes.add_argument("--registries", type=Path)
+    modes.add_argument("--authority", type=Path)
+    args = parser.parse_args()
+    version = ET.parse(ROOT / "Directory.Build.local.props").findtext(".//Version")
+    if version != "0.17.0":
+        raise SystemExit("This observation is scoped to the coherent 0.17.0 release.")
+    mode = "registries" if args.registries else "authority"
+    output = args.registries or args.authority
+    report, failed = collect(mode, version)
+    report.update(version=version, observedUtc=datetime.now(timezone.utc).isoformat(),
+                  sourceCommit=os.environ.get("GITHUB_SHA"), runId=os.environ.get("GITHUB_RUN_ID"))
+    output.parent.mkdir(parents=True, exist_ok=True)
+    output.write_text(json.dumps(report, indent=2) + "\n")
+    print(f"{mode}: {'unexpected or unavailable observation' if failed else 'expected limited observations'}; see sanitized artifact")
+    return 1 if failed else 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/tests/release/test-release-admission.py b/tests/release/test-release-admission.py
new file mode 100644
index 00000000..aba0957d
--- /dev/null
+++ b/tests/release/test-release-admission.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""Offline checks of admission boundaries and meaningful provider response controls."""
+import importlib.util
+from pathlib import Path
+import sys
+import unittest
+from unittest.mock import patch
+import urllib.request
+
+sys.dont_write_bytecode = True
+
+ROOT = Path(__file__).resolve().parents[2]
+spec = importlib.util.spec_from_file_location("admission", Path(__file__).with_name("observe-release-admission.py"))
+admission = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(admission)
+
+
+class AdmissionTests(unittest.TestCase):
+    def test_expected_registry_absence_and_authenticated_predecessor(self):
+        with patch.dict(admission.os.environ, FEED_TOKEN="offline-placeholder"), patch.object(admission, "observe", side_effect=[200] + [404] * 8):
+            report, failed = admission.collect("registries", "0.17.0")
+        self.assertFalse(failed)
+        self.assertEqual(len(report["packages"]), 8)
+
+    def test_registry_collision_unauthorized_and_unavailable_refuse(self):
+        for status in (200, 401, 403, 0):
+            with self.subTest(status=status), patch.dict(admission.os.environ, FEED_TOKEN="offline-placeholder"), patch.object(admission, "observe", side_effect=[200, status] + [404] * 7):
+                self.assertTrue(admission.collect("registries", "0.17.0")[1])
+
+    def test_predecessor_404_does_not_prove_registry_authentication(self):
+        with patch.dict(admission.os.environ, FEED_TOKEN="offline-placeholder"), patch.object(admission, "observe", return_value=404):
+            self.assertTrue(admission.collect("registries", "0.17.0")[1])
+
+    def test_oidc_success_cannot_prove_adapter_creation_scope(self):
+        with patch.dict(admission.os.environ, NUGET_API_KEY="offline-placeholder"), patch.object(admission, "observe", side_effect=[200, 200, 200, 404]):
+            report, failed = admission.collect("authority", "0.17.0")
+        self.assertFalse(failed)
+        self.assertEqual(report["newAdapterCreationScope"], "not-exposed-and-unproven")
+        self.assertEqual(report["packages"][-1]["authority"], "unproven")
+
+    def test_foreign_redirect_does_not_forward_credentials(self):
+        request = urllib.request.Request("https://www.nuget.org/api/v2/verifykey/example", headers={"X-NuGet-ApiKey": "offline-placeholder", "Authorization": "offline-placeholder"})
+        redirected = admission.SafeRedirect().redirect_request(request, None, 302, "Found", {}, "https://other.example/result")
+        self.assertNotIn("Authorization", redirected.headers)
+        self.assertNotIn("X-nuget-apikey", redirected.headers)
+
+    def test_existing_package_authority_failure_refuses(self):
+        with patch.dict(admission.os.environ, NUGET_API_KEY="offline-placeholder"), patch.object(admission, "observe", side_effect=[403, 200, 200, 404]):
+            self.assertTrue(admission.collect("authority", "0.17.0")[1])
+
+    def test_workflow_observation_cannot_enter_publisher(self):
+        text = (ROOT / ".github/workflows/release.yml").read_text()
+        excluded = "&& (github.event_name != 'workflow_dispatch' || inputs.admission_only != true)"
+        self.assertEqual(text.count(excluded), 2)
+        job = text.split("\n  admission:\n", 1)[1]
+        self.assertIn("github.event_name == 'workflow_dispatch' && inputs.admission_only == true", job)
+        for effect in ("dotnet", "nuget push", "source_run_id }}'", "GenerateTrustedPublisherPolicy"):
+            self.assertNotIn(effect, job)
+        self.assertIn('test -z "$SOURCE_RUN_ID"', job)
+        self.assertNotIn("ref:", job)
+
+
+if __name__ == "__main__":
+    unittest.main()