Use safer clangd defaults for enrichment

docs/lsp.md

@@ -27,7 +27,7 @@ Sixteen servers ship in the registry today
 | `typescript-language-server` | `typescript-language-server`     | typescript, javascript      | 5                |
 | `pyright`                    | `pyright-langserver`             | python                      | 5                |
 | `rust-analyzer`              | `rust-analyzer`                  | rust                        | 5                |
-| `clangd`                     | `clangd --background-index`      | c, c++, objc, objc++        | 5                |
+| `clangd`                     | `clangd --background-index=false --clang-tidy=false --header-insertion=never -j=1` | c, c++, objc, objc++ | 5                |
 | `jdtls`                      | `jdtls`                          | java                        | 6                |
 | `kotlin-language-server`     | `kotlin-language-server`         | kotlin                      | 6                |
 | `omnisharp`                  | `omnisharp -lsp`                 | csharp                      | 5                |
@@ -47,6 +47,12 @@ binary on `PATH`:
 - `ruby-lsp` → falls back to `solargraph stdio`.
 - `phpactor` → falls back to `intelephense --stdio`.
 
+The built-in `clangd` spec disables background indexing and clang-tidy by
+default because semantic enrichment needs request-driven graph evidence,
+not lint diagnostics or a persistent project index. Repositories that want
+those clangd features can override the `clangd` provider args in
+`.gortex.yaml`.
+
 Lower priority numbers win when more than one provider serves the same
 language. `gopls` is `3` so it beats SCIP-based providers (`5`) for Go;
 `jdtls` is `6` so it's lower-priority than the SCIP-java path that

internal/semantic/lsp/registry.go

@@ -319,11 +319,18 @@ var Servers = []ServerSpec{
 	{
 		Name:    "clangd",
 		Command: "clangd",
-		// `--background-index` keeps a project-wide symbol index hot in
-		// the daemon, which is essential for type-hierarchy precision in
-		// large C++ trees. `--header-insertion=never` avoids tactical
-		// edits when we only want graph signal.
-		Args:      []string{"--background-index", "--header-insertion=never"},
+		// Gortex uses clangd for request-driven graph evidence during
+		// enrichment, not lint diagnostics or a persistent project index.
+		// Keep clang-tidy and background indexing off by default so broad
+		// repo .clang-tidy configs and large C++ trees do not dominate CPU
+		// or crash-loop the enrichment subprocess. Users can opt back in via
+		// a semantic.providers override in .gortex.yaml.
+		Args: []string{
+			"--background-index=false",
+			"--clang-tidy=false",
+			"--header-insertion=never",
+			"-j=1",
+		},
 		Languages: []string{"c", "cpp", "objc", "objcpp"},
 		Extensions: []string{
 			".c", ".h",

internal/semantic/lsp/registry_test.go

@@ -1,6 +1,7 @@
 package lsp
 
 import (
+	"slices"
 	"strings"
 	"testing"
 
@@ -179,6 +180,27 @@ func TestPyreflyAndTsgoSpecs(t *testing.T) {
 	}
 }
 
+// TestClangdSpecUsesSafeEnrichmentDefaults pins clangd's built-in
+// enrichment argv. Gortex needs request-driven graph signal from
+// clangd, not repo clang-tidy diagnostics or a persistent background
+// project index.
+func TestClangdSpecUsesSafeEnrichmentDefaults(t *testing.T) {
+	clangd := SpecByName("clangd")
+	if clangd == nil {
+		t.Fatal("clangd spec not registered")
+	}
+
+	want := []string{
+		"--background-index=false",
+		"--clang-tidy=false",
+		"--header-insertion=never",
+		"-j=1",
+	}
+	if got := clangd.Args; !slices.Equal(got, want) {
+		t.Fatalf("clangd args = %v, want %v", got, want)
+	}
+}
+
 // TestSpecWithOverrides verifies .gortex.yaml command / args / env
 // overrides are applied to a copy without mutating the built-in spec —
 // the path by which jdtls gets a pinned JRE and launcher args.