diff --git a/Dockerfile b/Dockerfile
index 5d09f4c..6e50be1 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -14,7 +14,7 @@ COPY .forgejo/workflows/image.yaml ./.forgejo/workflows/image.yaml
 COPY schemas/ ./schemas/
 COPY k8s/ ./k8s/
 COPY scripts/render_gitops.py scripts/check_gitops_promotion.py ./scripts/
-RUN uv sync --frozen --extra dev && uv run --no-sync python scripts/render_gitops.py --check --verify-frontend --verify-platform && uv run --no-sync pytest -q -p no:cacheprovider tests/test_frontend_patterns.py tests/test_instruction_evaluation.py tests/test_admin_sync_api.py tests/test_gitops_release.py tests/test_release_broker.py
+RUN uv sync --frozen --extra dev && uv run --no-sync python scripts/render_gitops.py --check --verify-frontend --verify-platform && uv run --no-sync pytest -q -p no:cacheprovider tests/test_frontend_patterns.py tests/test_instruction_evaluation.py tests/test_admin_sync_api.py tests/test_gitops_release.py tests/test_release_broker.py tests/test_release_transport.py
 
 # Stage 2 — runtime image
 FROM python:3.12-slim@sha256:78387bc3881b8273120a12ebe6c1ab22b018ccc2c9adf565ae1ac9b536e184ea AS runtime
diff --git a/docs/release-broker.md b/docs/release-broker.md
index c699569..a76b21c 100644
--- a/docs/release-broker.md
+++ b/docs/release-broker.md
@@ -42,19 +42,18 @@ Failed rollback retains the active slot. Retried publication/sync must be
 idempotent, using compare-and-swap and accepting already-at-target as success.
 The adapter must refuse any unexpected third revision rather than overwriting it.
 
-Tests use generated fixture keys and an in-memory adapter. They prove policy and
-state-machine behavior, including restart and failed-health rollback; they are
-**not** proof of production Git/ArgoCD rollback or admitted authority.
+Tests use generated fixture keys, disposable real Git repositories and a simulated
+Kubernetes transport. They prove signed admission, real Git publication/rollback,
+concurrent-writer rejection and lost-push-response recovery. Kubernetes authorization,
+production credentials and live Git/ArgoCD rollback are **not** proven by these fixtures.
 
 ## Still required before activation
 
-1. Implement and verify an authenticated transport adapter that resolves exact
-   source commits, compares rendered manifests to the signed hashes, publishes
-   only the platform child revision field, and runs the fixed selective syncs.
-   Every network operation needs a bounded timeout; health must wait within that
-   bound for the exact revision and verify deployments, report sink and schedules.
-   It must persist/recover the platform commit across lost responses and serialize
-   with other writers. A generic repository-write token is not path enforcement.
+1. Admit and exercise the implemented transport adapter against an isolated
+   authenticated Git/Kubernetes environment. Supply the actual bounded report/schedule
+   invariant probe, pinned cluster UID and immutable credential/context configuration.
+   Verify the real authorization denials and restart behavior; simulated Kubernetes
+   responses do not prove those. A generic repository-write token is not path enforcement.
 2. Admit the dedicated principal and credential custody through the owner lane.
    ArgoCD Core has no API-server token lane. Kubernetes Application patch RBAC
    alone cannot restrict fields: keep it behind the reviewed broker boundary.
@@ -70,3 +69,40 @@ state-machine behavior, including restart and failed-health rollback; they are
 
 Platform enforcement contract: `railiance-platform/docs/activity-core-release-admission.md`.
 These requirements remain live work in ACTIVITY-WP-0041-T03 and RPF-WP-0048-T02.
+
+
+## Transport and observer implementation
+
+`release_transport.GitArgoBackend` retrieves both full source commits from the fixed
+activity-core repository and compares parsed manifest hashes with the admitted
+binding. It accepts only the audited static `runtime.yaml` Kustomization; proposed
+source cannot execute a renderer/plugin. Git publication creates a commit changing
+only the platform child revision field. Non-force pushes reject concurrent branch
+advances. After a lost response, remote Git is the durable source of truth: a retry
+accepts already-at-target and selective sync uses the current verified platform tip.
+Unexpected third revisions and unrelated changed paths stop the operation.
+
+The adapter verifies the operator-pinned kube-system namespace UID before Git
+publication or Kubernetes access. Context/credentials must remain immutable during
+its lifetime. Every subprocess is non-shell, with timeouts and sanitized failures.
+Kubernetes JSON patches compare resourceVersion and spec before setting the fixed
+sync operation. Existing foreign operations are never overwritten. Root sync selects
+only activity-core; child sync never prunes. Health checks require exact revision,
+Synced/Healthy and all three deployments ready at their observed generations, plus
+a mandatory report/schedule invariant probe. That trusted callback must itself use
+bounded I/O; no production probe is supplied or implied by the fixture implementation.
+Polling windows are bounded, with individual command timeout overhead possible.
+
+`release_observer.HealthObserver` records samples durably. It requires consecutive
+healthy samples of one revision with gaps no greater than 90 seconds. Failed samples,
+revision changes and missed samples reset the interval; clock regression durably
+invalidates it. Attestation requires a complete 24-hour sampled interval and a fresh
+last sample, including after restart. This is evidence at a bounded sampling cadence,
+not a claim that every instant between samples was observed. Two distant healthy
+snapshots cannot establish the interval. New observers start from their first actual
+sample; they do not backfill the earlier deployment timestamp.
+
+Neither module is connected to a production schedule, endpoint or credential source.
+Trusted signer custody, real invariant probes, Temporal dispatch and isolated
+Kubernetes authorization/rollback tests remain required before activation. Production
+revision and the deployment observation clock are unchanged by this source-only work.
diff --git a/src/activity_core/release_observer.py b/src/activity_core/release_observer.py
new file mode 100644
index 0000000..a14d0ed
--- /dev/null
+++ b/src/activity_core/release_observer.py
@@ -0,0 +1,69 @@
+"""Persistent, gap-sensitive health observations; no scheduler or signing key here."""
+from datetime import datetime, timedelta, timezone
+import sqlite3
+
+from .release_operations import revision
+
+
+class HealthObserver:
+    def __init__(self, database, *, max_gap_seconds=90):
+        if not 1 <= max_gap_seconds <= 90:
+            raise ValueError('health gap must be at most 90 seconds')
+        self.database, self.max_gap = database, timedelta(seconds=max_gap_seconds)
+        with self.connect() as db:
+            db.execute('CREATE TABLE IF NOT EXISTS observations (at TEXT PRIMARY KEY, revision TEXT NOT NULL, healthy INTEGER NOT NULL, since TEXT)')
+            db.execute('CREATE TABLE IF NOT EXISTS observer_guard (singleton INTEGER PRIMARY KEY, invalidated INTEGER NOT NULL)')
+            db.execute('INSERT OR IGNORE INTO observer_guard VALUES (1,0)')
+
+    def connect(self):
+        db=sqlite3.connect(self.database,timeout=5,isolation_level=None)
+        db.execute('PRAGMA synchronous=FULL')
+        return db
+
+    def observe(self, commit, healthy, now=None):
+        """Called by a trusted sampler after exact-revision readiness/invariant checks.
+
+        Failed/unavailable probes must be recorded False. A missed sample, clock
+        regression or revision change resets the interval; no timestamp backfill.
+        """
+        revision(commit)
+        if type(healthy) is not bool:raise ValueError('explicit boolean health required')
+        now=now or datetime.now(timezone.utc)
+        if now.tzinfo is None:raise ValueError('timezone required')
+        db=self.connect()
+        try:
+            db.execute('BEGIN IMMEDIATE')
+            prior=db.execute('SELECT at,revision,healthy,since FROM observations ORDER BY rowid DESC LIMIT 1').fetchone()
+            invalidated=db.execute('SELECT invalidated FROM observer_guard WHERE singleton=1').fetchone()[0]
+            since=now.isoformat() if healthy else None
+            if prior:
+                last=datetime.fromisoformat(prior[0])
+                if now<=last:
+                    db.execute('UPDATE observer_guard SET invalidated=1 WHERE singleton=1')
+                    db.commit()
+                    raise ValueError('non-increasing observation time')
+                if not invalidated and healthy and prior[2] and prior[1]==commit and now-last<=self.max_gap:
+                    since=prior[3]
+            db.execute('INSERT INTO observations VALUES (?,?,?,?)',(now.isoformat(),commit,int(healthy),since))
+            db.execute('UPDATE observer_guard SET invalidated=0 WHERE singleton=1')
+            db.commit()
+            return since
+        except Exception:
+            db.rollback();raise
+        finally:db.close()
+
+    def attestation(self, commit, now=None):
+        """Return facts for a trusted health issuer, never fabricate a signature."""
+        revision(commit);now=now or datetime.now(timezone.utc)
+        db=self.connect()
+        try:
+            row=db.execute('SELECT at,revision,healthy,since FROM observations ORDER BY rowid DESC LIMIT 1').fetchone()
+            if db.execute('SELECT invalidated FROM observer_guard WHERE singleton=1').fetchone()[0]:
+                raise ValueError('observation interval invalidated by clock regression')
+        finally:db.close()
+        if not row or row[1]!=commit or not row[2] or not row[3]:raise ValueError('no healthy revision interval')
+        measured=datetime.fromisoformat(row[0]);since=datetime.fromisoformat(row[3])
+        if not timedelta(0)<=now-measured<=self.max_gap:raise ValueError('health observations stale or clock regressed')
+        if measured-since<timedelta(hours=24):raise ValueError('24-hour observed interval incomplete')
+        return {'revision':commit,'continuous':True,'healthy':True,'synced':True,
+                'healthy_since':since.isoformat(),'observed_at':measured.isoformat()}
diff --git a/src/activity_core/release_transport.py b/src/activity_core/release_transport.py
new file mode 100644
index 0000000..42d0a9b
--- /dev/null
+++ b/src/activity_core/release_transport.py
@@ -0,0 +1,183 @@
+"""Fixed Git and Kubernetes transport for an admitted release broker.
+
+Credentials and context are operator-provided process configuration. No bearer
+values, URLs, arbitrary commands or repository paths are accepted from a release.
+There is no service endpoint or automatic production activation in this module.
+"""
+from __future__ import annotations
+
+import json
+import os
+from pathlib import Path
+import subprocess
+import time
+
+import yaml
+
+from .release_broker import fingerprint
+from .release_operations import APPLICATION_PATH, revision, sync_operations, update_child
+
+PLATFORM_URL='https://forgejo.coulomb.social/coulomb/railiance-platform.git'
+ACTIVITY_URL='https://forgejo.coulomb.social/coulomb/activity-core.git'
+
+
+class TransportError(RuntimeError):
+    pass
+
+
+def run(argv, *, input=None, env=None, timeout=30):
+    """Bounded, non-shell invocation; suppress outputs that could contain credentials."""
+    try:
+        return subprocess.run(argv,input=input,text=True,capture_output=True,check=True,
+                              timeout=timeout,env=env).stdout
+    except (subprocess.SubprocessError,OSError):
+        raise TransportError('release transport command failed or timed out') from None
+
+
+class GitArgoBackend:
+    def __init__(self, plan, workspace, invariants, *, cluster_uid, admitted=False, runner=run,
+                 clock=time.monotonic, pause=time.sleep, wait_seconds=90):
+        if not admitted:raise ValueError('transport identity not admitted')
+        if not callable(invariants):raise ValueError('report and schedule invariant probe required')
+        if not 1<=wait_seconds<=90:raise ValueError('bounded wait required')
+        if not isinstance(cluster_uid,str) or not cluster_uid:raise ValueError('pinned cluster UID required')
+        self.cluster_uid=cluster_uid;self.cluster_verified=False
+        self.plan=dict(plan);self.workspace=Path(workspace);self.invariants=invariants
+        self.runner,self.clock,self.pause,self.wait_seconds=runner,clock,pause,wait_seconds
+        if plan.get('repository')!='coulomb/activity-core' or plan.get('application')!='activity-core':
+            raise ValueError('transport plan outside scope')
+        for name in ('candidate','rollback'):revision(plan[name])
+        self.workspace.mkdir(parents=True,exist_ok=True,mode=0o700)
+        # Environment is trusted service configuration, not producer input. In
+        # particular kubeconfig and Git's credential helper belong to this identity.
+        self.env={**os.environ,'GIT_TERMINAL_PROMPT':'0','GIT_AUTHOR_NAME':'activity-core release broker',
+                  'GIT_AUTHOR_EMAIL':'release-broker@activity-core.invalid',
+                  'GIT_COMMITTER_NAME':'activity-core release broker',
+                  'GIT_COMMITTER_EMAIL':'release-broker@activity-core.invalid'}
+        self.platform=self.workspace/'platform.git';self.activity=self.workspace/'activity.git'
+        for path in (self.platform,self.activity):
+            if not path.exists():self.runner(['git','init','--bare',str(path)],env=self.env,timeout=30)
+
+    def git(self, repo, *args, input=None):
+        result=self.runner(['git','-c','core.hooksPath=/dev/null','-c','protocol.file.allow=never',
+                            '-C',str(repo),*args],input=input,env=self.env,timeout=30)
+        return result if args[0]=='show' else result.strip()
+
+    def head(self):
+        self.git(self.platform,'fetch','--no-tags',PLATFORM_URL,'main')
+        return revision(self.git(self.platform,'rev-parse','FETCH_HEAD'))
+
+    def validate_sources(self):
+        for key,hash_key in [('rollback','before_sha256'),('candidate','after_sha256')]:
+            commit=self.plan[key]
+            self.git(self.activity,'fetch','--no-tags',ACTIVITY_URL,commit)
+            body=self.git(self.activity,'show',commit+':k8s/gitops/runtime.yaml')
+            docs=list(yaml.safe_load_all(body))
+            if fingerprint(docs)!=self.plan[hash_key]:raise ValueError('source commit manifest binding mismatch')
+            # Never execute kustomize/plugins from a proposed source. Only the
+            # audited single static resource file is accepted by this lane.
+            kustomization=yaml.safe_load(self.git(self.activity,'show',commit+':k8s/gitops/kustomization.yaml'))
+            if kustomization!={'apiVersion':'kustomize.config.k8s.io/v1beta1','kind':'Kustomization','resources':['runtime.yaml']}:
+                raise ValueError('source rendering outside static projection contract')
+
+    def publish_revision(self, expected, target):
+        self.verify_cluster()
+        if {expected,target}!={self.plan['candidate'],self.plan['rollback']}:
+            raise ValueError('revision outside admitted release')
+        self.validate_sources()
+        base=self.head()
+        document=self.git(self.platform,'show',base+':'+APPLICATION_PATH)
+        updated=update_child(document,expected,target)
+        if updated==document:return  # Recovery after a lost push response.
+        blob=self.git(self.platform,'hash-object','-w','--stdin',input=updated)
+        # The trusted per-broker workspace is serialized by Broker's ledger lock.
+        self.git(self.platform,'read-tree',base)
+        self.git(self.platform,'update-index','--add','--cacheinfo','100644',blob,APPLICATION_PATH)
+        tree=self.git(self.platform,'write-tree')
+        commit=self.git(self.platform,'commit-tree',tree,'-p',base,input='Promote activity-core to '+target+'\n')
+        changed=self.git(self.platform,'diff-tree','--no-commit-id','--name-only','-r',commit)
+        if changed!=APPLICATION_PATH:raise ValueError('publication contains unrelated paths')
+        # Non-force push rejects concurrent branch advances. A retry fetches the
+        # new tip and repeats the child-revision compare-and-swap.
+        self.git(self.platform,'push',PLATFORM_URL,revision(commit)+':refs/heads/main')
+
+    def verify_cluster(self):
+        if not self.cluster_verified:
+            uid=self.runner(['kubectl','--request-timeout=20s','get','namespace','kube-system',
+                             '-o','jsonpath={.metadata.uid}'],env=self.env,timeout=25).strip()
+            if uid!=self.cluster_uid:raise ValueError('cluster identity mismatch')
+            self.cluster_verified=True
+
+    def kube(self, *args, input=None):
+        self.verify_cluster()
+        return self.runner(['kubectl','--request-timeout=20s',*args],input=input,env=self.env,timeout=25)
+
+    def app(self, name):
+        if name not in {'railiance-apps-root','activity-core'}:raise ValueError('foreign application')
+        obj=json.loads(self.kube('-n','argocd','get','application',name,'-o','json'))
+        if obj.get('metadata',{}).get('name')!=name or obj['metadata'].get('namespace')!='argocd':
+            raise ValueError('application identity mismatch')
+        if name=='railiance-apps-root':
+            source=obj.get('spec',{}).get('source',{})
+            if (source.get('repoURL')!=PLATFORM_URL or source.get('path')!='argocd/railiance01/applications'
+                    or source.get('targetRevision')!='main' or obj['spec'].get('syncPolicy',{}).get('automated') is not None):
+                raise ValueError('root outside release contract')
+        else:
+            current=obj.get('spec',{}).get('source',{}).get('targetRevision')
+            # Reuse validation without changing the live object.
+            update_child(yaml.safe_dump(obj),revision(current),current)
+        return obj
+
+    def _sync(self, name, body):
+        desired=body['operation']['sync'];obj=self.app(name)
+        operation=obj.get('operation')
+        if operation is not None:
+            active=dict(operation.get('sync',{}));active.setdefault('prune',False)
+            if active!=desired:raise ValueError('another ArgoCD operation is active')
+        done=obj.get('status',{}).get('operationState',{})
+        completed=(done.get('phase')=='Succeeded' and done.get('syncResult',{}).get('revision')==desired['revision'])
+        if operation is None and not completed:
+            patch=[{'op':'test','path':'/metadata/resourceVersion','value':obj['metadata']['resourceVersion']},
+                   {'op':'test','path':'/spec','value':obj['spec']},
+                   {'op':'add','path':'/operation','value':body['operation']}]
+            self.kube('-n','argocd','patch','application',name,'--type=json','--patch-file=/dev/stdin',input=json.dumps(patch))
+        until=self.clock()+self.wait_seconds
+        while self.clock()<until:
+            state=self.app(name).get('status',{}).get('operationState',{})
+            result=state.get('syncResult',{}).get('revision')
+            if result==desired['revision']:
+                if state.get('phase')=='Succeeded':return
+                if state.get('phase') in {'Failed','Error'}:raise TransportError('ArgoCD sync failed')
+            self.pause(1)
+        raise TransportError('ArgoCD sync wait timed out')
+
+    def sync_revision(self, target):
+        if target not in {self.plan['candidate'],self.plan['rollback']}:raise ValueError('unbound revision')
+        base=self.head()
+        document=self.git(self.platform,'show',base+':'+APPLICATION_PATH)
+        # Publication must remain the current source tip; never sync a stale pin.
+        update_child(document,target,target)
+        root,child=sync_operations(base,target)
+        self._sync(*root)
+        if self.app('activity-core')['spec']['source']['targetRevision']!=target:
+            raise ValueError('selective root sync did not set expected child revision')
+        self._sync(*child)
+
+    def healthy(self, target):
+        if target not in {self.plan['candidate'],self.plan['rollback']}:raise ValueError('unbound revision')
+        until=self.clock()+self.wait_seconds
+        while self.clock()<until:
+            obj=self.app('activity-core');status=obj.get('status',{})
+            synced=(obj['spec']['source']['targetRevision']==target
+                    and status.get('sync',{}).get('revision')==target
+                    and status.get('sync',{}).get('status')=='Synced'
+                    and status.get('health',{}).get('status')=='Healthy')
+            if synced:
+                ready=True
+                for name in ('actcore-api','actcore-worker','actcore-event-router'):
+                    d=json.loads(self.kube('-n','activity-core','get','deployment',name,'-o','json'))
+                    n=d['spec'].get('replicas',1);s=d.get('status',{})
+                    ready &= n>0 and s.get('observedGeneration')==d['metadata']['generation'] and all(s.get(k,0)==n for k in ('readyReplicas','updatedReplicas','availableReplicas'))
+                if ready and self.invariants(target) is True:return True
+            self.pause(1)
+        return False
diff --git a/tests/test_release_transport.py b/tests/test_release_transport.py
new file mode 100644
index 0000000..619edf6
--- /dev/null
+++ b/tests/test_release_transport.py
@@ -0,0 +1,191 @@
+"""Real disposable Git repositories; simulated Kubernetes boundary."""
+import copy
+import json
+import subprocess
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+import pytest
+import yaml
+
+from activity_core.release_broker import fingerprint
+from activity_core.release_observer import HealthObserver
+from activity_core.release_operations import APPLICATION_PATH
+from activity_core.release_transport import ACTIVITY_URL, PLATFORM_URL, GitArgoBackend, TransportError, run
+NOW=datetime(2026,9,28,16,tzinfo=timezone.utc)
+
+ROOT=Path(__file__).resolve().parents[1]
+
+
+def git(path,*args):
+    return subprocess.check_output(['git','-C',str(path),*args],text=True,stderr=subprocess.DEVNULL).strip()
+
+
+def init(path):
+    path.mkdir();git(path,'init','-b','main');git(path,'config','user.name','Fixture');git(path,'config','user.email','fixture@example.invalid')
+
+
+def commit(path):
+    git(path,'add','.');git(path,'commit','-m','fixture');return git(path,'rev-parse','HEAD')
+
+
+@pytest.fixture
+def transport(tmp_path):
+    activity=tmp_path/'activity';init(activity)
+    k=activity/'k8s/gitops';k.mkdir(parents=True)
+    before=list(yaml.safe_load_all((ROOT/'k8s/gitops/runtime.yaml').read_text()))
+    (k/'runtime.yaml').write_text(yaml.safe_dump_all(before));(k/'kustomization.yaml').write_text((ROOT/'k8s/gitops/kustomization.yaml').read_text())
+    rollback=commit(activity)
+    after=copy.deepcopy(before)
+    next(d for d in after if d['metadata']['name']=='actcore-worker')['spec']['template']['spec']['containers'][0]['image']='forgejo.coulomb.social/coulomb/activity-core@sha256:'+'f'*64
+    (k/'runtime.yaml').write_text(yaml.safe_dump_all(after));candidate=commit(activity)
+    seed=tmp_path/'seed';init(seed);p=seed/APPLICATION_PATH;p.parent.mkdir(parents=True)
+    child={'apiVersion':'argoproj.io/v1alpha1','kind':'Application','metadata':{'name':'activity-core','namespace':'argocd'},'spec':{'project':'activity-core','source':{'repoURL':ACTIVITY_URL,'path':'k8s/gitops','targetRevision':rollback},'destination':{'namespace':'activity-core','server':'https://kubernetes.default.svc'},'syncPolicy':{'syncOptions':['CreateNamespace=false','ApplyOutOfSyncOnly=true','PruneLast=true','FailOnSharedResource=true']}}}
+    p.write_text(yaml.safe_dump(child));commit(seed)
+    platform=tmp_path/'platform.git';git(tmp_path,'clone','--bare',str(seed),str(platform))
+    plan={'repository':'coulomb/activity-core','application':'activity-core','candidate':candidate,'rollback':rollback,'before_sha256':fingerprint(before),'after_sha256':fingerprint(after)}
+    state={'tick':0,'calls':[],'lose_push':False,'fail_health':False}
+    root={'metadata':{'name':'railiance-apps-root','namespace':'argocd','resourceVersion':'1'},'spec':{'source':{'repoURL':PLATFORM_URL,'path':'argocd/railiance01/applications','targetRevision':'main'}}}
+    child['metadata']['resourceVersion']='1';apps={'railiance-apps-root':root,'activity-core':child}
+    def runner(argv,**kwargs):
+        if argv[0]=='git':
+            argv=[str(activity) if a==ACTIVITY_URL else str(platform) if a==PLATFORM_URL else 'protocol.file.allow=always' if a=='protocol.file.allow=never' else a for a in argv]
+            result=run(argv,**kwargs)
+            if 'push' in argv and state['lose_push']:
+                state['lose_push']=False;raise TransportError('fixture lost push response')
+            return result
+        state['calls'].append(argv)
+        if 'get' in argv:
+            i=argv.index('get');kind,name=argv[i+1:i+3]
+            if kind=='namespace':return 'fixture-cluster'
+            if kind=='application':return json.dumps(apps[name])
+            return json.dumps({'metadata':{'generation':1},'spec':{'replicas':1},'status':{'observedGeneration':1,'readyReplicas':1,'updatedReplicas':1,'availableReplicas':1}})
+        i=argv.index('patch');name=argv[i+2];patch=json.loads(kwargs['input']);obj=apps[name]
+        assert patch[0]=={'op':'test','path':'/metadata/resourceVersion','value':obj['metadata']['resourceVersion']}
+        assert patch[1]=={'op':'test','path':'/spec','value':obj['spec']}
+        operation=patch[2]['value'];sync=operation['sync'];assert sync['prune'] is False
+        if name=='railiance-apps-root':
+            assert sync['resources']==[{'group':'argoproj.io','kind':'Application','name':'activity-core','namespace':'argocd'}]
+            source=yaml.safe_load(git(platform,'show',sync['revision']+':'+APPLICATION_PATH))
+            apps['activity-core']['spec']=source['spec']
+        obj['status']={'operationState':{'phase':'Succeeded','syncResult':{'revision':sync['revision']}},'sync':{'status':'Synced','revision':sync['revision']},'health':{'status':'Healthy'}}
+        return '{}'
+    def pause(seconds):state['tick']+=seconds
+    backend=GitArgoBackend(plan,tmp_path/'broker',lambda target:not(state['fail_health'] and target==candidate),cluster_uid='fixture-cluster',admitted=True,runner=runner,clock=lambda:state['tick'],pause=pause,wait_seconds=2)
+    return backend,plan,state,platform,apps,before,after
+
+
+def test_real_git_publish_recover_sync_and_rollback(transport):
+    b,p,state,platform,apps,*_=transport
+    before=git(platform,'rev-parse','main');state['lose_push']=True
+    with pytest.raises(TransportError):b.publish_revision(p['rollback'],p['candidate'])
+    published=git(platform,'rev-parse','main');assert published!=before
+    b.publish_revision(p['rollback'],p['candidate'])
+    assert git(platform,'rev-parse','main')==published
+    assert git(platform,'diff-tree','--no-commit-id','--name-only','-r',published)==APPLICATION_PATH
+    b.sync_revision(p['candidate']);assert b.healthy(p['candidate'])
+    state['fail_health']=True;assert not b.healthy(p['candidate'])
+    b.publish_revision(p['candidate'],p['rollback']);b.sync_revision(p['rollback']);assert b.healthy(p['rollback'])
+    assert apps['activity-core']['spec']['source']['targetRevision']==p['rollback']
+
+
+def test_manifest_tampering_refused_before_push(transport):
+    b,p,state,platform,*_=transport;before=git(platform,'rev-parse','main');b.plan['after_sha256']='0'*64
+    with pytest.raises(ValueError,match='manifest binding'):b.publish_revision(p['rollback'],p['candidate'])
+    assert git(platform,'rev-parse','main')==before
+    assert not any('patch' in c for c in state['calls'])
+
+
+def test_no_unbound_target_or_unadmitted_transport(transport,tmp_path):
+    b,p,*_=transport
+    with pytest.raises(ValueError):b.publish_revision(p['rollback'],'c'*40)
+    with pytest.raises(ValueError):b.sync_revision('c'*40)
+    with pytest.raises(ValueError):GitArgoBackend(p,tmp_path/'denied',lambda _:True,cluster_uid='fixture-cluster')
+
+
+def test_active_foreign_operation_not_overwritten(transport):
+    b,p,state,platform,apps,*_=transport
+    b.publish_revision(p['rollback'],p['candidate'])
+    apps['railiance-apps-root']['operation']={'sync':{'revision':'d'*40,'prune':True}}
+    with pytest.raises(ValueError,match='active'):b.sync_revision(p['candidate'])
+    assert not any('patch' in c for c in state['calls'])
+
+
+def test_health_observer_requires_samples_and_survives_restart(tmp_path):
+    o=HealthObserver(tmp_path/'health.sqlite');sha='a'*40
+    o.observe(sha,True,NOW)
+    o.observe(sha,True,NOW+timedelta(hours=24))
+    with pytest.raises(ValueError,match='incomplete'):o.attestation(sha,NOW+timedelta(hours=24))
+    start=NOW+timedelta(hours=24)
+    for n in range(1,1441):o.observe(sha,True,start+timedelta(minutes=n))
+    restarted=HealthObserver(tmp_path/'health.sqlite')
+    result=restarted.attestation(sha,start+timedelta(hours=24))
+    assert result['healthy_since']==start.isoformat()
+    with pytest.raises(ValueError,match='stale'):restarted.attestation(sha,start+timedelta(hours=24,minutes=2))
+    restarted.observe(sha,False,start+timedelta(hours=24,minutes=1))
+    with pytest.raises(ValueError,match='no healthy'):restarted.attestation(sha,start+timedelta(hours=24,minutes=1))
+
+
+def test_observer_revision_change_and_clock_regression(tmp_path):
+    o=HealthObserver(tmp_path/'health.sqlite');o.observe('a'*40,True,NOW)
+    with pytest.raises(ValueError,match='non-increasing'):o.observe('a'*40,True,NOW)
+    t=NOW+timedelta(seconds=60)
+    assert o.observe('b'*40,True,t)==t.isoformat()
+    with pytest.raises(ValueError):o.attestation('a'*40,t)
+
+
+def test_concurrent_git_writer_is_not_overwritten(transport):
+    b,p,state,platform,apps,*_=transport
+    original=b.runner
+    def racing(argv,**kwargs):
+        if argv[0]=='git' and 'push' in argv:
+            # Inject another committed platform update after broker's CAS read.
+            tree=git(platform,'rev-parse','main^{tree}')
+            parent=git(platform,'rev-parse','main')
+            env=dict(b.env)
+            new=run(['git','-C',str(platform),'commit-tree',tree,'-p',parent],input='concurrent writer',env=env).strip()
+            git(platform,'update-ref','refs/heads/main',new,parent)
+        return original(argv,**kwargs)
+    b.runner=racing
+    with pytest.raises(TransportError):b.publish_revision(p['rollback'],p['candidate'])
+    current=yaml.safe_load(git(platform,'show','main:'+APPLICATION_PATH))
+    assert current['spec']['source']['targetRevision']==p['rollback']
+
+
+def test_broker_rolls_back_using_real_git_transport(transport,tmp_path):
+    from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+    from cryptography.hazmat.primitives.serialization import Encoding,PublicFormat
+    from activity_core.release_broker import Broker,Receipts,ROLES
+    from tests.test_release_broker import envelopes
+    b,p,state,platform,apps,before,after=transport
+    keys={role:Ed25519PrivateKey.generate() for role in ROLES}
+    trust={r:{'public_key':k.public_key().public_bytes(Encoding.Raw,PublicFormat.Raw),'principal':r,'roles':{r}} for r,k in keys.items()}
+    broker=Broker(tmp_path/'coordinator.sqlite',Receipts(trust),admitted=True)
+    signed=envelopes(before,after,keys,candidate=p['candidate'],rollback=p['rollback'])
+    rid=broker.admit(before,after,p['candidate'],p['rollback'],signed,NOW)
+    state['fail_health']=True
+    phases=[]
+    for _ in range(10):
+        phases.append(broker.advance(rid,b,NOW))
+        if phases[-1]=='rolled_back':break
+    assert phases==['publish_pending','published','synced','rollback_planned','rollback_published','rollback_synced','rolled_back']
+    assert apps['activity-core']['spec']['source']['targetRevision']==p['rollback']
+    assert yaml.safe_load(git(platform,'show','main:'+APPLICATION_PATH))['spec']['source']['targetRevision']==p['rollback']
+
+
+def test_clock_regression_invalidates_interval_until_new_sample(tmp_path):
+    o=HealthObserver(tmp_path/'health.sqlite');sha='a'*40
+    o.observe(sha,True,NOW)
+    with pytest.raises(ValueError):o.observe(sha,True,NOW-timedelta(seconds=1))
+    with pytest.raises(ValueError,match='invalidated'):HealthObserver(tmp_path/'health.sqlite').attestation(sha,NOW)
+    later=NOW+timedelta(seconds=30)
+    assert o.observe(sha,True,later)==later.isoformat()
+
+
+def test_wrong_cluster_refused_before_git_publication(transport):
+    b,p,state,platform,*_=transport
+    before=git(platform,'rev-parse','main');b.cluster_uid='wrong-cluster'
+    with pytest.raises(ValueError,match='cluster identity'):
+        b.publish_revision(p['rollback'],p['candidate'])
+    assert git(platform,'rev-parse','main')==before
+    assert not any('patch' in c for c in state['calls'])
diff --git a/workplans/ACTIVITY-WP-0041-gitops-adoption.md b/workplans/ACTIVITY-WP-0041-gitops-adoption.md
index 8bd28ca..a0b0b43 100644
--- a/workplans/ACTIVITY-WP-0041-gitops-adoption.md
+++ b/workplans/ACTIVITY-WP-0041-gitops-adoption.md
@@ -169,3 +169,25 @@ continuous observer, Temporal dispatch and isolated transport/rollback proof.
 The broker is disabled by default and not connected to live credentials or a
 production schedule. Current deployed revision and healthy-soak clock are unchanged.
 T03 stays progress; the full unattended acceptance is not complete.
+
+## Transport adapter and sampled health observer — 2026-09-27
+
+Implemented the fixed Git/ArgoCD adapter: exact source/hash verification, static
+Kustomization restriction, one-field child revision commits, non-force publication,
+remote-tip recovery after lost responses, cluster UID binding, resourceVersion/spec
+CAS, selective sync and deployment health checks. A bounded report/schedule probe
+remains a required trusted integration. Implemented persistent health sampling with
+90-second maximum gaps, revision/failure reset, clock-regression invalidation and
+24-hour attestation refusal unless the complete sample interval exists.
+
+Tests use disposable real Git repositories and simulated Kubernetes responses.
+The broker completes failed-health rollback through the real Git adapter; tests
+cover lost push responses, concurrent publication, source tampering, wrong cluster,
+foreign Argo operations and observer restart/gaps. Latest focused suite: 48 passed;
+full affected suite before the final cluster-binding test: 75 passed. CI includes
+all these tests. No production credentials or activation were introduced.
+
+T03 remains progress for admitted identity/custody, authenticated isolated Kubernetes
+verification, real build/review/retention issuers, production invariant probes,
+Temporal observer/dispatcher registration and evidence sinks. The implemented
+observer cannot retroactively assert the earlier soak interval. See docs/release-broker.md.