fix(mcp): workspace_state distinguishes not-configured from no-repos

When `~/.codegraph/workspace.yml` didn't exist, `workspace_state`
returned `{workspace_size: 0, repos: []}` — same shape as a configured
but empty workspace. LLMs read this as "everything is broken".

Result now carries a `status` field:
- `workspace_not_configured` when the YAML doesn't exist
- `workspace_empty` when it exists with no repos
- `ok` when there's at least one repo

The not-configured case includes a message clarifying that the local
single-repo MCP tools work independently — only the cross-repo tools
are affected.

v0.1.2 backlog item #9.

Author: smochan

CHANGELOG.md

@@ -100,6 +100,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ...}`. New `GraphNotBuiltError` exposed from
   `codegraph.mcp_server.server` for callers that want to handle it
   explicitly.
+- **`workspace_state` MCP tool now distinguishes "not configured" from
+  "no repos".** When `~/.codegraph/workspace.yml` didn't exist, the
+  tool returned `{workspace_size: 0, repos: []}` — indistinguishable
+  from a configured-but-empty workspace. LLMs paraphrased this as
+  "everything is broken" and cascaded into wrong-answer territory.
+  Result now carries a `status` field
+  (`workspace_not_configured` / `workspace_empty` / `ok`) with an
+  actionable message: "local-graph MCP tools work independently — this
+  only affects cross-repo tools. Run `codegraph workspace init` …".
 
 ## [0.1.1] — 2026-05-24
 

codegraph/mcp_server/server.py

@@ -798,8 +798,26 @@ def _handle_workspace_state(
     from codegraph.workspace.config import load_workspace, resolve_workspace_path
     from codegraph.workspace.operations import workspace_state
 
-    cfg = load_workspace(resolve_workspace_path())
-    return workspace_state(cfg)
+    workspace_path = resolve_workspace_path()
+    if not workspace_path.exists():
+        return {
+            "status": "workspace_not_configured",
+            "workspace_path": str(workspace_path),
+            "message": (
+                "polycodegraph: no workspace configured at "
+                f"{workspace_path}. The local-graph MCP tools (find_symbol, "
+                "callers, callees, blast_radius, dataflow_trace, …) work "
+                "independently — this only affects the cross-repo workspace "
+                "tools. Run `codegraph workspace init` then "
+                "`codegraph workspace add <path>` to enable them."
+            ),
+            "workspace_size": 0,
+            "repos": [],
+        }
+    cfg = load_workspace(workspace_path)
+    result = workspace_state(cfg)
+    result["status"] = "ok" if cfg.repos else "workspace_empty"
+    return result
 
 
 @_register(

tests/test_workspace_state_status.py

@@ -0,0 +1,44 @@
+"""Tests for `workspace_state` status field (v0.1.2 #9)."""
+from __future__ import annotations
+
+from pathlib import Path
+
+import yaml
+
+from codegraph.mcp_server.server import _handle_workspace_state
+
+
+def test_workspace_not_configured_when_file_missing(
+    tmp_path: Path, monkeypatch
+) -> None:
+    monkeypatch.setenv(
+        "CODEGRAPH_WORKSPACE_FILE", str(tmp_path / "nope" / "workspace.yml")
+    )
+    result = _handle_workspace_state(None, {})
+    assert result["status"] == "workspace_not_configured"
+    assert "codegraph workspace init" in result["message"]
+    assert "local-graph MCP tools" in result["message"]
+    assert result["workspace_size"] == 0
+    assert result["repos"] == []
+
+
+def test_workspace_empty_when_file_exists_with_no_repos(
+    tmp_path: Path, monkeypatch
+) -> None:
+    f = tmp_path / "workspace.yml"
+    f.write_text(yaml.dump({"repos": []}))
+    monkeypatch.setenv("CODEGRAPH_WORKSPACE_FILE", str(f))
+    result = _handle_workspace_state(None, {})
+    assert result["status"] == "workspace_empty"
+    assert result["workspace_size"] == 0
+
+
+def test_workspace_ok_when_repos_present(tmp_path: Path, monkeypatch) -> None:
+    repo = tmp_path / "myrepo"
+    repo.mkdir()
+    f = tmp_path / "workspace.yml"
+    f.write_text(yaml.dump({"repos": [{"path": str(repo), "name": "myrepo"}]}))
+    monkeypatch.setenv("CODEGRAPH_WORKSPACE_FILE", str(f))
+    result = _handle_workspace_state(None, {})
+    assert result["status"] == "ok"
+    assert result["workspace_size"] == 1