diff --git a/DIAGNOSTIC_TESTS.yaml b/DIAGNOSTIC_TESTS.yaml
index c7f71e3..21188d6 100644
--- a/DIAGNOSTIC_TESTS.yaml
+++ b/DIAGNOSTIC_TESTS.yaml
@@ -363,7 +363,7 @@ input: "{{> footer }}"
 should: warn
 expected: |
   first -3 is equivalent to last 3
-    --> /home/spencer/github.com/sbrow.github.io/thor/mustache/fixtures/layouts/partials/footer.html:11:78
+    --> fixtures/layouts/partials/footer.html:11:78
      |
    9 |       href="https://edwardtufte.github.io/tufte-css/">Tufte CSS</a>
   10 |   </p>
diff --git a/flake.nix b/flake.nix
index f90ade1..b4072e1 100644
--- a/flake.nix
+++ b/flake.nix
@@ -162,6 +162,7 @@
 
               # IDE
               unstable.helix
+              claude-code
               typescript-language-server
               vscode-langservers-extracted
             ]);
diff --git a/mustache/diagnostic_test.odin b/mustache/diagnostic_test.odin
index 6aa15ca..c3920c4 100644
--- a/mustache/diagnostic_test.odin
+++ b/mustache/diagnostic_test.odin
@@ -513,7 +513,18 @@ diag_ctx :: proc() -> Diag_Context {
 diag_partials :: proc() -> map[string]Template {
 	dirs := [?]string{#directory, "fixtures/layouts/partials"}
 	partials_dir, _ := filepath.join(dirs[:], context.temp_allocator)
-	return load_partials(partials_dir, allocator = context.temp_allocator)
+	partials := load_partials(partials_dir, allocator = context.temp_allocator)
+	// #directory expands to an absolute, build-environment-specific path (e.g.
+	// /build/... inside the nix sandbox vs a local checkout). Strip it so
+	// partial diagnostics reference a stable path across environments, keeping
+	// the golden expected output deterministic.
+	for key, tmpl in partials {
+		t := tmpl
+		rel := strings.trim_prefix(t.path, #directory)
+		t.path = strings.trim_left(rel, "/")
+		partials[key] = t
+	}
+	return partials
 }
 
 diag_slug :: proc(name: string) -> string {