Map the default namespace to the shared docs root in get_doc_content

An explicit namespace:"default" resolved files under namespaces/default/
while resolvedRagIndexPath and retrieve_docs treat default as the shared
docs root, so the same document was reachable with namespace omitted but
not with it spelled out. Route default through the shared branch. Also
drop the redundant retrieveDocsFromDB keep-alive var.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: tae2089

internal/mcp/handler_docs.go

@@ -216,8 +216,10 @@ func (h *handlers) getDocContent(ctx context.Context, request mcp.CallToolReques
 		return mcp.NewToolResultError("invalid file_path: path traversal not allowed"), nil
 	}
 
+	// The default namespace maps to the shared docs root, mirroring resolvedRagIndexPath
+	// and retrieve_docs; only named namespaces resolve under namespaces/<ns>/.
 	var resolvedPath string
-	if namespace != "" {
+	if namespace != "" && ctxns.Normalize(namespace) != ctxns.DefaultNamespace {
 		if err := validateNamespacePath(namespace, filePath); err != nil {
 			return mcp.NewToolResultError(err.Error()), nil
 		}
@@ -326,8 +328,6 @@ type retrieveDocsResponse = retrieval.Response
 // @intent keep MCP retrieve_docs result decoding compatible while sharing the canonical retrieval DTO.
 type retrieveDocsResult = retrieval.Result
 
-var _ = (*handlers).retrieveDocsFromDB
-
 // @intent build a retrieve_docs response from persisted graph nodes and annotation tags.
 // @requires SearchBackend and DB must be configured, and ctx must carry the desired namespace.
 // @ensures returned results are grouped one-per-file in first-seen FTS order and keep retrieve_docs' stable JSON shape.

internal/mcp/handler_docs_test.go

@@ -295,6 +295,33 @@ func TestGetDocContent_PathTraversal(t *testing.T) {
 	}
 }
 
+func TestGetDocContent_DefaultNamespaceReadsSharedDocs(t *testing.T) {
+	deps := setupTestDeps(t)
+	deps.RagIndexDir = t.TempDir()
+
+	content := "# Shared Doc\nfrom shared docs root"
+	docPath := filepath.Join(deps.RagIndexDir, "docs", "shared-doc.md")
+	if err := os.MkdirAll(filepath.Dir(docPath), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(docPath, []byte(content), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	// "default" must resolve to the shared docs root, matching resolvedRagIndexPath
+	// and retrieve_docs (contentNamespace maps default to shared), not namespaces/default/.
+	result := callTool(t, deps, "get_doc_content", map[string]any{
+		"namespace": "default",
+		"file_path": "docs/shared-doc.md",
+	})
+	if result.IsError {
+		t.Fatalf("default namespace should read shared docs, got error: %v", getTextContent(result))
+	}
+	if got := getTextContent(result); got != content {
+		t.Errorf("want %q, got %q", content, got)
+	}
+}
+
 func TestGetDocContent_NotFound(t *testing.T) {
 	deps := setupTestDeps(t)
 	result := callTool(t, deps, "get_doc_content", map[string]any{