diff --git a/apps/api/src/api/git_repositories.py b/apps/api/src/api/git_repositories.py
index 4d04789..b00a20d 100644
--- a/apps/api/src/api/git_repositories.py
+++ b/apps/api/src/api/git_repositories.py
@@ -89,6 +89,32 @@ def _get_repo_path(user_id: uuid.UUID, project_id: uuid.UUID, name: str) -> str:
     return os.path.join(base, str(user_id), str(project_id), f"{name}.git")
 
 
+def _build_provider_clone_url(owner: str, repo: str) -> str:
+    """Build the SSH clone URL for the fixed git provider."""
+    return f"git@git.commumedia.org:{owner}/{repo}.git"
+
+
+def _preflight_remote_repository(remote_url: str) -> None:
+    """Verify a remote repository is reachable before cloning."""
+    try:
+        result = subprocess.run(
+            ["git", "ls-remote", remote_url],
+            capture_output=True,
+            text=True,
+            timeout=60,
+        )
+    except subprocess.TimeoutExpired:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="remote repository check timed out")
+    except FileNotFoundError:
+        raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail="git command not found")
+
+    if result.returncode != 0:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="repository not found or inaccessible",
+        )
+
+
 class GitRepositoryCreate(BaseModel):
     name: str
     remote_url: str | None = None
@@ -267,6 +293,9 @@ async def create_repository(
         if parse_result["base_url"]:
             remote_url = parse_result["base_url"]
 
+    if remote_url:
+        _preflight_remote_repository(remote_url)
+
     repo_path = _get_repo_path(user_id, project_id, data.name)
 
     # Ensure parent directory exists
diff --git a/apps/api/tests/unit/test_git_repository_clone_preflight.py b/apps/api/tests/unit/test_git_repository_clone_preflight.py
new file mode 100644
index 0000000..5381879
--- /dev/null
+++ b/apps/api/tests/unit/test_git_repository_clone_preflight.py
@@ -0,0 +1,28 @@
+from unittest.mock import Mock, patch
+
+import pytest
+from fastapi import HTTPException
+
+from src.api.git_repositories import _build_provider_clone_url, _preflight_remote_repository
+
+
+def test_build_provider_clone_url_uses_fixed_host() -> None:
+    assert _build_provider_clone_url("alice", "demo") == "git@git.commumedia.org:alice/demo.git"
+
+
+def test_preflight_remote_repository_allows_accessible_repo() -> None:
+    completed = Mock(returncode=0)
+    with patch("src.api.git_repositories.subprocess.run", return_value=completed) as run_mock:
+        _preflight_remote_repository("git@git.commumedia.org:alice/demo.git")
+
+    run_mock.assert_called_once()
+
+
+def test_preflight_remote_repository_rejects_missing_repo() -> None:
+    completed = Mock(returncode=128)
+    with patch("src.api.git_repositories.subprocess.run", return_value=completed):
+        with pytest.raises(HTTPException) as exc_info:
+            _preflight_remote_repository("git@git.commumedia.org:alice/missing.git")
+
+    assert exc_info.value.status_code == 400
+    assert exc_info.value.detail == "repository not found or inaccessible"
diff --git a/apps/web/src/components/repositories-settings-tab.test.tsx b/apps/web/src/components/repositories-settings-tab.test.tsx
index eccecc6..54bbf56 100644
--- a/apps/web/src/components/repositories-settings-tab.test.tsx
+++ b/apps/web/src/components/repositories-settings-tab.test.tsx
@@ -46,8 +46,39 @@ describe("RepositoriesSettingsTab", () => {
     fireEvent.change(screen.getByPlaceholderText(/repository-name/i), {
       target: { value: "New Repo" },
     });
-    fireEvent.click(screen.getByLabelText(/clone existing repository/i));
-    fireEvent.change(screen.getByPlaceholderText(/github.com\/user\/repo.git/i), {
+    fireEvent.change(screen.getByPlaceholderText(/owner/i), {
+      target: { value: "alice" },
+    });
+    fireEvent.change(screen.getByPlaceholderText(/repo-name/i), {
+      target: { value: "demo" },
+    });
+    fireEvent.click(screen.getByRole("button", { name: /clone repository/i }));
+
+    await waitFor(() => {
+      expect(createMock).toHaveBeenCalledWith("proj-1", {
+        name: "New Repo",
+        remote_url: "git@git.commumedia.org:alice/demo.git",
+      });
+    });
+    expect(listMock).toHaveBeenCalledTimes(2);
+  });
+
+  it("uses advanced url fallback when requested", async () => {
+    const listMock = vi.spyOn(gitRepositoriesApi, "listRepositories").mockResolvedValue(mockRepositories);
+    const createMock = vi.spyOn(gitRepositoriesApi, "createRepository").mockResolvedValue(mockRepositories[0]);
+
+    render(<RepositoriesSettingsTab />);
+
+    await waitFor(() => {
+      expect(screen.getByText("Main Repo")).toBeInTheDocument();
+    });
+
+    fireEvent.click(screen.getByRole("button", { name: /add repository/i }));
+    fireEvent.change(screen.getByPlaceholderText(/repository-name/i), {
+      target: { value: "New Repo" },
+    });
+    fireEvent.click(screen.getByRole("button", { name: /use full url instead/i }));
+    fireEvent.change(screen.getByPlaceholderText(/https:\/\/github.com\/user\/repo.git/i), {
       target: { value: "https://github.com/user/repo.git" },
     });
     fireEvent.click(screen.getByRole("button", { name: /clone repository/i }));
@@ -73,9 +104,11 @@ describe("RepositoriesSettingsTab", () => {
     fireEvent.change(screen.getByPlaceholderText(/repository-name/i), {
       target: { value: "New Repo" },
     });
-    fireEvent.click(screen.getByLabelText(/clone existing repository/i));
+    fireEvent.change(screen.getByPlaceholderText(/owner/i), {
+      target: { value: "" },
+    });
     fireEvent.click(screen.getByRole("button", { name: /clone repository/i }));
 
-    expect(screen.getByText(/remote url is required/i)).toBeInTheDocument();
+    expect(screen.getByText(/owner and repository name are required/i)).toBeInTheDocument();
   });
 });
diff --git a/apps/web/src/components/repository-create-dialog.tsx b/apps/web/src/components/repository-create-dialog.tsx
index 5c58521..dda7269 100644
--- a/apps/web/src/components/repository-create-dialog.tsx
+++ b/apps/web/src/components/repository-create-dialog.tsx
@@ -17,7 +17,10 @@ interface RepositoryCreateDialogProps {
 export const RepositoryCreateDialog = ({ projectId, open, title, onClose, onCreated }: RepositoryCreateDialogProps) => {
   const [createMode, setCreateMode] = useState<CreateMode>("clone");
   const [formName, setFormName] = useState("");
-  const [formRemoteUrl, setFormRemoteUrl] = useState("");
+  const [owner, setOwner] = useState("");
+  const [repoName, setRepoName] = useState("");
+  const [advancedUrl, setAdvancedUrl] = useState("");
+  const [useAdvancedUrl, setUseAdvancedUrl] = useState(false);
   const [formError, setFormError] = useState<string | null>(null);
   const [urlValidation, setUrlValidation] = useState<{
     status: UrlValidationStatus;
@@ -34,12 +37,16 @@ export const RepositoryCreateDialog = ({ projectId, open, title, onClose, onCrea
 
   useEffect(() => {
     if (!open) return;
+    if (!useAdvancedUrl) {
+      setUrlValidation({ status: "idle", result: null });
+      return;
+    }
 
     if (debounceTimer.current) {
       clearTimeout(debounceTimer.current);
     }
 
-    if (!formRemoteUrl.trim()) {
+    if (!advancedUrl.trim()) {
       setUrlValidation({ status: "idle", result: null });
       return;
     }
@@ -48,7 +55,7 @@ export const RepositoryCreateDialog = ({ projectId, open, title, onClose, onCrea
 
     debounceTimer.current = setTimeout(async () => {
       try {
-        const result = await parseGitUrl(formRemoteUrl.trim());
+        const result = await parseGitUrl(advancedUrl.trim());
         if (result.is_valid_clone_url) {
           setUrlValidation({ status: "valid", result });
         } else if (result.needs_parsing) {
@@ -66,12 +73,15 @@ export const RepositoryCreateDialog = ({ projectId, open, title, onClose, onCrea
         clearTimeout(debounceTimer.current);
       }
     };
-  }, [formRemoteUrl, open]);
+  }, [advancedUrl, open, useAdvancedUrl]);
 
   const resetForm = () => {
     setCreateMode("clone");
     setFormName("");
-    setFormRemoteUrl("");
+    setOwner("");
+    setRepoName("");
+    setAdvancedUrl("");
+    setUseAdvancedUrl(false);
     setFormError(null);
     setUrlValidation({ status: "idle", result: null });
   };
@@ -90,27 +100,41 @@ export const RepositoryCreateDialog = ({ projectId, open, title, onClose, onCrea
       return;
     }
 
-    if (createMode === "clone" && !formRemoteUrl.trim()) {
-      setFormError("Remote URL is required to clone an existing repository");
-      return;
-    }
-
     try {
       const input: GitRepositoryCreate = {
         name: formName.trim(),
-        remote_url: formRemoteUrl.trim() || undefined,
+        remote_url: undefined,
       };
+
+      if (createMode === "clone") {
+        if (useAdvancedUrl) {
+          if (!advancedUrl.trim()) {
+            setFormError("Remote URL is required for advanced cloning");
+            return;
+          }
+          input.remote_url = advancedUrl.trim();
+        } else {
+          if (!owner.trim() || !repoName.trim()) {
+            setFormError("Owner and repository name are required");
+            return;
+          }
+          input.remote_url = `git@git.commumedia.org:${owner.trim()}/${repoName.trim()}.git`;
+        }
+      }
+
       await createRepository(projectId, input);
       handleClose();
       await onCreated();
-    } catch {
-      setFormError("Failed to create repository");
+    } catch (error: unknown) {
+      const response = error as { response?: { data?: { detail?: string } } };
+      const detail = response.response?.data?.detail;
+      setFormError(typeof detail === "string" ? detail : "Failed to create repository");
     }
   };
 
   const handleUseSuggestedUrl = () => {
     if (urlValidation.result?.base_url) {
-      setFormRemoteUrl(urlValidation.result.base_url);
+      setAdvancedUrl(urlValidation.result.base_url);
       setUrlValidation({ status: "idle", result: null });
       setFormError(null);
     }
@@ -136,7 +160,7 @@ export const RepositoryCreateDialog = ({ projectId, open, title, onClose, onCrea
       <div className="dialog">
         <h3>{title}</h3>
         <p className="muted">
-          Clone an existing repository from a git server, or create a blank bare repo here.
+          Clone an existing repository from git.commumedia.org, or create a blank bare repo here.
         </p>
         <form onSubmit={handleSubmit} className="stack">
           <div className="form-field">
@@ -168,46 +192,85 @@ export const RepositoryCreateDialog = ({ projectId, open, title, onClose, onCrea
               placeholder="repository-name"
             />
           </label>
-          <label className="form-field">
-            Remote URL {createMode === "clone" ? "(required)" : "(optional)"}
-            <input
-              type="text"
-              value={formRemoteUrl}
-              onChange={(event) => setFormRemoteUrl(event.target.value)}
-              placeholder="https://github.com/user/repo.git"
-              className={getUrlInputClass()}
-            />
-            {urlValidation.status === "validating" && (
-              <span className="validation-status validating">Validating...</span>
-            )}
-            {urlValidation.status === "valid" && (
-              <span className="validation-status valid">
-                <Icon name="success" size="sm" /> Valid git URL
-              </span>
-            )}
-            {urlValidation.status === "needs-parsing" && urlValidation.result && (
-              <div className="url-suggestion">
-                <span className="validation-status warning">
-                  <Icon name="warning" size="sm" /> This looks like a browser URL
+          {createMode === "clone" && !useAdvancedUrl && (
+            <>
+              <label className="form-field">
+                Owner
+                <input
+                  type="text"
+                  value={owner}
+                  onChange={(event) => setOwner(event.target.value)}
+                  placeholder="owner"
+                />
+              </label>
+              <label className="form-field">
+                Repository
+                <input
+                  type="text"
+                  value={repoName}
+                  onChange={(event) => setRepoName(event.target.value)}
+                  placeholder="repo-name"
+                />
+              </label>
+              <p className="muted">SSH target: git@git.commumedia.org:{owner || "owner"}/{repoName || "repo"}.git</p>
+              <button
+                type="button"
+                className="secondary-button small"
+                onClick={() => setUseAdvancedUrl(true)}
+              >
+                Use full URL instead
+              </button>
+            </>
+          )}
+          {createMode === "clone" && useAdvancedUrl && (
+            <label className="form-field">
+              Remote URL
+              <input
+                type="text"
+                value={advancedUrl}
+                onChange={(event) => setAdvancedUrl(event.target.value)}
+                placeholder="https://github.com/user/repo.git"
+                className={getUrlInputClass()}
+              />
+              {urlValidation.status === "validating" && (
+                <span className="validation-status validating">Validating...</span>
+              )}
+              {urlValidation.status === "valid" && (
+                <span className="validation-status valid">
+                  <Icon name="success" size="sm" /> Valid git URL
                 </span>
-                <div className="suggestion-actions">
-                  <span className="suggested-url">Suggested: {urlValidation.result.base_url}</span>
-                  <button
-                    type="button"
-                    className="secondary-button small"
-                    onClick={handleUseSuggestedUrl}
-                  >
-                    Use Suggested
-                  </button>
+              )}
+              {urlValidation.status === "needs-parsing" && urlValidation.result && (
+                <div className="url-suggestion">
+                  <span className="validation-status warning">
+                    <Icon name="warning" size="sm" /> This looks like a browser URL
+                  </span>
+                  <div className="suggestion-actions">
+                    <span className="suggested-url">Suggested: {urlValidation.result.base_url}</span>
+                    <button
+                      type="button"
+                      className="secondary-button small"
+                      onClick={handleUseSuggestedUrl}
+                    >
+                      Use Suggested
+                    </button>
+                  </div>
                 </div>
-              </div>
-            )}
-            {urlValidation.status === "invalid" && (
-              <span className="validation-status invalid">
-                <Icon name="error" size="sm" /> Invalid URL
-              </span>
-            )}
-          </label>
+              )}
+              {urlValidation.status === "invalid" && (
+                <span className="validation-status invalid">
+                  <Icon name="error" size="sm" /> Invalid URL
+                </span>
+              )}
+              <button
+                type="button"
+                className="secondary-button small"
+                onClick={() => setUseAdvancedUrl(false)}
+              >
+                Use owner/repo instead
+              </button>
+            </label>
+          )}
           {formError && (
             <div className="error-message">
               <p className="error-text">{formError}</p>
diff --git a/docs/features/repositories.md b/docs/features/repositories.md
index 216bcea..a338ffd 100644
--- a/docs/features/repositories.md
+++ b/docs/features/repositories.md
@@ -12,7 +12,7 @@ Git repositories are managed within projects. You can create bare repositories f
 2. Click the **"New Repository"** button
 3. Fill in the form:
    - **Name**: Repository name (required)
-   - **Remote URL**: For cloning (optional)
+   - **Owner** and **Repository**: For SSH cloning from `git.commumedia.org`
    - **Mirror Clone**: Toggle for mirror clones
 4. Click **"Create Repository"**
 
@@ -25,12 +25,12 @@ Creates a new bare git repository. Use this for:
 
 #### Clone from Remote
 
-Enter a git URL to clone from:
-- `https://github.com/user/repo.git`
-- `git@github.com:user/repo.git`
-- `https://gitlab.com/user/repo.git`
+Enter the repository owner and name to clone from `git.commumedia.org` over SSH:
+- `owner`: `alice`
+- `repository`: `demo`
+- Resulting SSH URL: `git@git.commumedia.org:alice/demo.git`
 
-**Smart URL Parsing:** If you paste a browser URL (like `https://github.com/user/repo/tree/main`), the system will automatically suggest the correct git URL.
+**Advanced fallback:** If needed, you can still paste a full git URL and the system will suggest the correct clone URL.
 
 #### Mirror Clone
 
diff --git a/openspec/changes/git-repo-ssh-clone-check/.openspec.yaml b/openspec/changes/git-repo-ssh-clone-check/.openspec.yaml
new file mode 100644
index 0000000..4a1c677
--- /dev/null
+++ b/openspec/changes/git-repo-ssh-clone-check/.openspec.yaml
@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-05-22
diff --git a/openspec/changes/git-repo-ssh-clone-check/design.md b/openspec/changes/git-repo-ssh-clone-check/design.md
new file mode 100644
index 0000000..5829d65
--- /dev/null
+++ b/openspec/changes/git-repo-ssh-clone-check/design.md
@@ -0,0 +1,45 @@
+## Context
+
+The current repository creation flow already supports cloning remote repositories via `remote_url` and can normalize pasted browser URLs. However, the UI asks for a full URL, which is awkward for the fixed provider `git.commumedia.org`. The requested behavior is to enter `owner` and `repo`, check whether the repository exists, and clone only if it does.
+
+## Goals / Non-Goals
+
+**Goals:**
+- Accept SSH-only `owner` and `repo` inputs for cloning from `git.commumedia.org`
+- Verify repository existence before clone
+- Preserve full URL paste as a fallback path
+- Preserve blank repository creation
+- Reuse the existing repository create endpoint and shared dialog
+
+**Non-Goals:**
+- Supporting multiple git providers
+- Adding a remote repository discovery API
+- Supporting HTTPS clone flow for the new structured path
+- Changing repository storage or clone behavior beyond preflight validation
+
+## Decisions
+
+**1. Provider assumption**
+- Hardcode `git.commumedia.org` for the structured clone path
+- Build SSH URLs as `git@git.commumedia.org:{owner}/{repo}.git`
+
+**2. Existence check**
+- Use `git ls-remote` on the constructed SSH URL before cloning
+- If the command fails, surface a repository-not-found/inaccessible error and do not clone
+
+**3. UI structure**
+- Keep the shared repository creation dialog as the single entry point
+- In clone mode, collect `owner` and `repo` instead of asking for a full URL
+- Keep an advanced paste-URL fallback for existing behavior and browser URL parsing
+- Keep blank repository creation available in the same dialog
+
+**4. Backend behavior**
+- Reuse `POST /projects/{project_id}/repositories`
+- Add preflight logic before the existing `git clone --mirror`
+- Leave the database schema unchanged
+
+## Risks / Trade-offs
+
+**[Risk] SSH auth may still fail even if the repo exists** → Mitigation: preflight error should be explicit and user-facing.
+**[Risk] Command availability** → Mitigation: reuse the same `git` dependency already required for cloning.
+**[Risk] UI complexity** → Mitigation: keep the dialog shared and minimal, with fallback URL paste.
diff --git a/openspec/changes/git-repo-ssh-clone-check/proposal.md b/openspec/changes/git-repo-ssh-clone-check/proposal.md
new file mode 100644
index 0000000..66e512c
--- /dev/null
+++ b/openspec/changes/git-repo-ssh-clone-check/proposal.md
@@ -0,0 +1,25 @@
+## Why
+
+Repository creation already supports cloning from a remote URL, but the current UI only accepts a full URL. For the common fixed-provider case (`git.commumedia.org`), users should be able to enter `owner` and `repo` and have the app verify the repository exists before cloning. If the repository does not exist, the app should surface a clear error. Existing blank repository creation must remain available.
+
+## What Changes
+
+- Change the shared repository create dialog to support an SSH-only clone form with `owner` and `repo`
+- Build the clone target as `git@git.commumedia.org:{owner}/{repo}.git`
+- Preflight clone targets with `git ls-remote` before cloning
+- Return a clear error when the repository is missing or inaccessible
+- Keep the current full URL paste flow as an advanced fallback
+- Keep blank repository creation as a fallback option
+
+## Capabilities
+
+### Modified Capabilities
+
+- `git-repo`: Repository creation UX and clone validation reuse the existing create endpoint and clone path
+
+## Impact
+
+- Frontend: `repository-create-dialog.tsx`, `git-repositories.tsx`, `repositories-settings-tab.tsx`
+- Backend: `git_repositories.py` create endpoint clone preflight
+- Docs: repository creation guidance must reflect SSH-only owner/repo input
+- Tests: add coverage for SSH repo existence checks and fallback URL behavior
diff --git a/openspec/changes/git-repo-ssh-clone-check/tasks.md b/openspec/changes/git-repo-ssh-clone-check/tasks.md
new file mode 100644
index 0000000..542c7b6
--- /dev/null
+++ b/openspec/changes/git-repo-ssh-clone-check/tasks.md
@@ -0,0 +1,22 @@
+## 1. Backend - SSH Existence Check
+
+- [ ] 1.1 Add `git ls-remote` preflight to repository creation in `git_repositories.py`
+- [ ] 1.2 Build SSH clone URL from `owner` and `repo` for `git.commumedia.org`
+- [ ] 1.3 Return a clear error when the repository is missing or inaccessible
+
+## 2. Frontend - Structured Clone Form
+
+- [ ] 2.1 Update `RepositoryCreateDialog` clone mode to accept `owner` and `repo`
+- [ ] 2.2 Keep advanced full-URL paste flow and blank repository fallback
+- [ ] 2.3 Reuse the shared dialog from repository settings and repositories page
+
+## 3. Validation and Docs
+
+- [ ] 3.1 Update repository docs to explain SSH-only owner/repo input
+- [ ] 3.2 Add tests for success, missing repo, and URL fallback behavior
+
+## 4. Quality Gates
+
+- [ ] 4.1 Run backend and frontend targeted tests
+- [ ] 4.2 Run frontend typecheck and lint where applicable
+- [ ] 4.3 Commit and push changes