diff --git a/Cargo.lock b/Cargo.lock
index cd755e8..8296b07 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1379,7 +1379,6 @@ dependencies = [
  "ghostty-inspector",
  "ghostty-os",
  "ghostty-vt",
- "glib-build-tools",
  "glow",
  "gtk4",
  "gtk4-layer-shell",
@@ -1856,12 +1855,6 @@ dependencies = [
  "smallvec",
 ]
 
-[[package]]
-name = "glib-build-tools"
-version = "0.22.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f9871f38b67853c358b8190f77b9f878eb27d933a950f1045b244c4559a9f5f0"
-
 [[package]]
 name = "glib-macros"
 version = "0.22.9"
diff --git a/crates/ghostty-apprt-gtk/Cargo.toml b/crates/ghostty-apprt-gtk/Cargo.toml
index 288fbd7..21e7c2a 100644
--- a/crates/ghostty-apprt-gtk/Cargo.toml
+++ b/crates/ghostty-apprt-gtk/Cargo.toml
@@ -46,9 +46,6 @@ dear-imgui-glow = "0.19"
 glow = "0.18"
 wayland-sys = { version = "0.31.11", features = ["client", "dlopen"] }
 
-[build-dependencies]
-glib-build-tools = "0.22"
-
 [dev-dependencies]
 env_logger = "0.11"
 
diff --git a/crates/ghostty-apprt-gtk/build.rs b/crates/ghostty-apprt-gtk/build.rs
index d8a41fe..13c310e 100644
--- a/crates/ghostty-apprt-gtk/build.rs
+++ b/crates/ghostty-apprt-gtk/build.rs
@@ -73,9 +73,12 @@ fn main() {
     // neither blueprint-compiler nor glib-compile-resources (Zig:
     // `GhosttyDist.Resource` for `ghostty_resources.{c,h}`). As in Zig, it is
     // never used in a git checkout.
-    println!("cargo:rerun-if-changed=dist/ghostty.gresource");
     let prebuilt = manifest.join("dist/ghostty.gresource");
     if prebuilt.is_file() && !manifest.join("../../.git").exists() {
+        // Watch the bundle only when it is an input. In a checkout it is
+        // normally absent, and watching a missing file forces every build
+        // to recompile the resources and all dependent crates.
+        println!("cargo:rerun-if-changed=dist/ghostty.gresource");
         std::fs::copy(&prebuilt, out.join("ghostty.gresource")).unwrap();
         return;
     }
@@ -119,10 +122,24 @@ fn main() {
     let xml_path = out.join("ghostty.gresource.xml");
     std::fs::write(&xml_path, xml).unwrap();
 
-    glib_build_tools::compile_resources(
-        &[out.as_path(), res.as_path()],
-        xml_path.to_str().unwrap(),
-        "ghostty.gresource",
+    // glib-build-tools also watches the generated XML and UI files. Their
+    // timestamps change during this script, invalidating the next build.
+    // All actual inputs are already covered by the `resources` watch above.
+    let compiled = Command::new("glib-compile-resources")
+        .arg("--sourcedir")
+        .arg(&out)
+        .arg("--sourcedir")
+        .arg(&res)
+        .arg("--target")
+        .arg(out.join("ghostty.gresource"))
+        .arg(&xml_path)
+        .output()
+        .expect("`glib-compile-resources` is required to build ghostty-apprt-gtk");
+    assert!(
+        compiled.status.success(),
+        "glib-compile-resources failed with {}:\n{}",
+        compiled.status,
+        String::from_utf8_lossy(&compiled.stderr)
     );
 }
 
diff --git a/crates/ghostty-build-info/build.rs b/crates/ghostty-build-info/build.rs
index 93a89c0..d13471f 100644
--- a/crates/ghostty-build-info/build.rs
+++ b/crates/ghostty-build-info/build.rs
@@ -61,10 +61,13 @@ fn detect_version(manifest_dir: &Path) -> (String, Option<String>) {
         let git_dir = PathBuf::from(git_dir);
         println!("cargo:rerun-if-changed={}", git_dir.join("HEAD").display());
         println!("cargo:rerun-if-changed={}", git_dir.join("refs").display());
-        println!(
-            "cargo:rerun-if-changed={}",
-            git_dir.join("packed-refs").display()
-        );
+        // Missing watched paths make Cargo rerun this script on every build.
+        // Packing loose refs also changes `refs`, so it will register this
+        // optional file once Git creates it.
+        let packed_refs = git_dir.join("packed-refs");
+        if packed_refs.is_file() {
+            println!("cargo:rerun-if-changed={}", packed_refs.display());
+        }
     }
     let hash = run(
         "git",
diff --git a/docs/rewrite/ARCHITECTURE.md b/docs/rewrite/ARCHITECTURE.md
index 72faeea..5862419 100644
--- a/docs/rewrite/ARCHITECTURE.md
+++ b/docs/rewrite/ARCHITECTURE.md
@@ -70,6 +70,16 @@ ghostty-bench (benchmarks), ghostty-build-data (completions, man pages, syntax).
 Non-code: `resources/` (shell-integration, themes, terminfo), `dist/` (desktop
 integration), `po/` (translations), crate-local `res/`/`shaders/`/`resources/`.
 
+Build inputs: `ghostty-build-info/build.rs` derives version metadata from the
+workspace manifest and Git HEAD/refs, watching `packed-refs` only when it exists
+(packing loose refs also changes the watched `refs` directory). The GTK build
+script compiles `resources/` in checkouts and watches the optional
+`dist/ghostty.gresource` bundle only when consuming it from a source tarball.
+Missing optional files must not be emitted as Cargo `rerun-if-changed` inputs:
+they invalidate every subsequent build and rebuild downstream crates.
+GTK invokes `glib-compile-resources` directly so generated XML/UI files in
+`OUT_DIR` are not watched as inputs; the `resources/` watch covers their sources.
+
 ## Key design decisions
 
 1. **Safe Rust by default.** Workspace lint `unsafe_code = "forbid"`. Crates