diff --git a/packages/bus/tests/copy-revoke.test.mjs b/packages/bus/tests/copy-revoke.test.mjs
index 40356a836..d7b5865b4 100644
--- a/packages/bus/tests/copy-revoke.test.mjs
+++ b/packages/bus/tests/copy-revoke.test.mjs
@@ -62,11 +62,13 @@ async function world(t) {
 // they stand, as a restart of the bus process would; boot() runs the gate's boot proof and promotes.
 // stopRuns acknowledges each run the broker told the launcher to kill, as the launcher's exit does,
 // unless `ack` is false. The revoke's remote step goes to the organization's admin slot.
-async function org(t, w, { id = 'demo', name = 'rev', services = READ, perm = 'read', definition = 'research', admin = true, adminRotateBy = ahead(60), stopMs = 2000, project = null } = {}) {
+async function org(t, w, { id = 'demo', name = 'rev', services = READ, perm = 'read', definition = 'research', admin = true, adminRotateBy = ahead(60), stopMs = 2000, project = null, gitOnly = false } = {}) {
   const { root, rolesDir, api } = w;
   const owner = id === 'demo' ? 'owner' : id;
   const doc = { ...businessDoc(root, id), plugins: { harness: ['pi'] }, vars: { 'bus.tester': true } };
   doc.projects.stack.remote = `${api.url}/${owner}/stack`;
+  // A project set up in git remote mode names its repository there, with no top-level remote.
+  if (gitOnly) { doc.projects.stack.git = { mode: 'remote', remote: doc.projects.stack.remote }; delete doc.projects.stack.remote; }
   // The project root the organization service derives (archive and delete check it).
   doc.projects.stack.root = join(w.data, 'org-runtime', id, 'projects', 'stack');
   if (project) doc.projects.stack.agents = project;
@@ -651,6 +653,17 @@ test('CB4 an owner update cannot change the repository of a project a copy bindi
   await orgService.updateOrg(f.ctx, f.id, other, { ifRevision: revision });
 });
 
+test('CB4 the owner\'s project.remote.set cannot change the repository of a project a copy binding still grants; the revoke then finishes at Gitea', async (t) => {
+  const w = await world(t);
+  const { f, r } = await live(t, w, { gitOnly: true });
+  const { revision } = f.writer.read(f.id);
+  assert.throws(() => f.writer.setProjectRemote(f.id, { revision, project: 'stack', remote: `${w.api.url}/owner/elsewhere` }, 'jason'), refuses('project-repo-bound'));
+  assert.equal(f.writer.read(f.id).revision, revision);
+  const out = await f.call(f.human, 'credentials.revoke', { agent: f.name, service: 'gitea', reason: 'Owner revoke' });
+  assert.equal(out.state, 'unbound');
+  await assertRevoked(f, r, { cause: 'revoke', code: 'credential-revoked' });
+});
+
 test('CB4 a remote step whose bound server cannot be read, or whose record names another incarnation, fails and the copy stays fenced', async (t) => {
   const w = await world(t);
   const { f } = await live(t, w);
diff --git a/packages/organization/src/organization.mjs b/packages/organization/src/organization.mjs
index 3a8668802..3cf449fa8 100644
--- a/packages/organization/src/organization.mjs
+++ b/packages/organization/src/organization.mjs
@@ -12,6 +12,7 @@ import { isDailyModelQuota } from "../../plugins/src/model-quota.mjs";
 import { checkReplyLimits } from "../../library/src/limits.mjs";
 import { ADDITION_VERB, additionProblem } from "./project-bootstrap.mjs";
 import { remoteProblem, remoteTarget } from "./project-remotes.mjs";
+import { REPO_BOUND, projectBindings, repoBoundMessage } from "./repo-remote.mjs";
 import { orgIncarnation, withRegistryWriter } from "./org-registry.mjs";
 import { REMOTE_OUTCOMES, REVOKE_CAUSES, allGranted, bindingText, definitionPin, samePin } from "./copy-bindings.mjs";
 import { entryForm, projectAgentProblem, rootForProjectCheck } from "./agent-levels-write.mjs";
@@ -654,13 +655,21 @@ export function organizationWriter({ dir, rolesDir, dataRoot = null, barrier = (
   // The only exception to the projects fence for an existing software mapping.
   // Build from the locked document and check both the candidate and serialized bytes.
   function setProjectRemote(id, { revision, project, remote }, actor) {
+    // #1873 CB4 (F7): never under a copy binding that still grants the project, as in project repo set
+    // and the owner's update: a changed repository would strand that binding's remote revoke.
+    const refuseBound = (old) => {
+      const bound = projectBindings(old, project);
+      if (bound.length) fail(REPO_BOUND, repoBoundMessage(project, bound));
+    };
     const guard = (old, document) => {
       const agents = Object.entries(old.roles ?? {}).flatMap(([name, role]) => [name, `${role?.definition}.${name}`]);
       if (actor !== old.human || actor === "tester" || agents.includes(actor)) fail("human-required");
+      refuseBound(old);
       const problem = remoteProblem(old, document, project, remote);
       if (problem) fail(problem);
     };
     return commit(id, old => {
+      refuseBound(old);
       remoteTarget(old, project, remote);
       return { ...old, projects: { ...old.projects, [project]: { ...old.projects[project], remote } } };
     }, { revision, actor, guard, detail: { verb: "project.remote.set", project } });