diff --git a/internal/server/features_test.go b/internal/server/features_test.go
index 5641e2b..d1c35e3 100644
--- a/internal/server/features_test.go
+++ b/internal/server/features_test.go
@@ -55,16 +55,18 @@ func Epsilon() int { return 2 }
 
 // ---- Feature 1: ast_query format flag ----
 
-func TestASTQueryFormatVerboseDefault(t *testing.T) {
+func TestASTQueryFormatCompactDefault(t *testing.T) {
 	srv, tmpDir := newFeaturesServer(t)
 	ctx := context.Background()
 
-	req := mcp.CallToolRequest{}
-	req.Params.Arguments = map[string]interface{}{
+	// Default (no format arg) is compact: one line per match, no code blocks.
+	args := map[string]interface{}{
 		"pattern":  "func $NAME() string",
 		"language": "go",
 		"paths":    []interface{}{tmpDir},
 	}
+	req := mcp.CallToolRequest{}
+	req.Params.Arguments = args
 	res, err := srv.handleASTQuery(ctx, req)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
@@ -72,10 +74,19 @@ func TestASTQueryFormatVerboseDefault(t *testing.T) {
 	if res == nil || len(res.Content) == 0 {
 		t.Fatal("nil/empty result")
 	}
-	text := res.Content[0].(mcp.TextContent).Text
-	// verbose mode has code blocks
-	if !strings.Contains(text, "```") {
-		t.Errorf("verbose mode should have code blocks, got:\n%s", text)
+	if text := res.Content[0].(mcp.TextContent).Text; strings.Contains(text, "```") {
+		t.Errorf("compact default should NOT have code blocks, got:\n%s", text)
+	}
+
+	// Verbose remains available on explicit request.
+	args["format"] = "verbose"
+	req.Params.Arguments = args
+	res, err = srv.handleASTQuery(ctx, req)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if text := res.Content[0].(mcp.TextContent).Text; !strings.Contains(text, "```") {
+		t.Errorf("format=verbose should have code blocks, got:\n%s", text)
 	}
 }
 
diff --git a/internal/server/handlers_ast.go b/internal/server/handlers_ast.go
index ebc91a7..8865c5f 100644
--- a/internal/server/handlers_ast.go
+++ b/internal/server/handlers_ast.go
@@ -67,7 +67,10 @@ func (s *Server) resolveASTQueryParams(request mcp.CallToolRequest) (*astQueryPa
 		if prefsFormat != "" {
 			p.format = prefsFormat
 		} else {
-			p.format = "verbose"
+			// Default to compact (one line per match): far fewer tokens than
+			// verbose (full code + captures) on multi-match queries. Callers can
+			// opt into verbose per-call or via the default_format session pref.
+			p.format = "compact"
 		}
 	}
 
diff --git a/internal/server/help_content.go b/internal/server/help_content.go
index 5d30dbe..1414609 100644
--- a/internal/server/help_content.go
+++ b/internal/server/help_content.go
@@ -75,7 +75,7 @@ const helpASTQuery = "# ast_query — flags and examples\n\n" +
 	"| Flag | Effect |\n" +
 	"|------|--------|\n" +
 	"| `verbose=true` | Emit `Found N match(es):` preamble (v1 behaviour). Default: false. |\n" +
-	"| `format` | `verbose` (default, full code+captures) \\| `compact` (one line per match) \\| `location` (file:line only) |\n" +
+	"| `format` | `compact` (default, one line per match) \\| `verbose` (full code+captures) \\| `location` (file:line only) |\n" +
 	"| `cursor` | Opaque pagination token from a previous truncated response — fetches next page. |\n" +
 	"| `max_results` | Page size (default: 100). |\n" +
 	"| `name_exact` | Exact symbol name to match. |\n" +
diff --git a/internal/server/server.go b/internal/server/server.go
index 8afaf9a..13576da 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -251,7 +251,7 @@ func (s *Server) registerTools() {
 				mcp.Description("Maximum number of results to return (default: 100, page size for pagination)"),
 			),
 			mcp.WithString("format",
-				mcp.Description("Output format: \"verbose\" (default, full code+captures), \"compact\" (one line per match), \"location\" (file:line only)"),
+				mcp.Description("Output format: \"compact\" (default, one line per match), \"verbose\" (full code+captures), \"location\" (file:line only)"),
 			),
 			mcp.WithString("cursor",
 				mcp.Description("Pagination cursor from a previous truncated response. Pass back to fetch the next page."),