diff --git a/.github/workflows/external-tests.yml b/.github/workflows/external-tests.yml
index 2e8576b9d..15e6d3e78 100644
--- a/.github/workflows/external-tests.yml
+++ b/.github/workflows/external-tests.yml
@@ -55,7 +55,7 @@ jobs:
 
       - name: Build Rust binary
         shell: bash
-        run: make build
+        run: make build-e2e
 
       - name: Verify Windows DLL has no unexpected dependencies
         if: matrix.os == 'windows-latest'
diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
index 43426ef91..ccc206329 100644
--- a/.github/workflows/python.yml
+++ b/.github/workflows/python.yml
@@ -15,6 +15,8 @@ on:
 env:
   CARGO_TERM_COLOR: always
   MACOSX_DEPLOYMENT_TARGET: "13.0"
+  CARGO_PROFILE_RELEASE_LTO: thin
+  CARGO_PROFILE_RELEASE_CODEGEN_UNITS: 16
 
 jobs:
   test:
@@ -31,7 +33,11 @@ jobs:
           persist-credentials: false
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
+        uses: actions-rust-lang/setup-rust-toolchain@v1.15.4
+        with:
+          cache: true
+          cache-on-failure: true
+          cache-key: "v1-rust-python"
 
       - name: Setup uv
         uses: astral-sh/setup-uv@v5
@@ -43,6 +49,8 @@ jobs:
         working-directory: packages/fff-python
         shell: bash
         run: |
-          uv sync --all-extras
+          # --no-install-project: uv would otherwise build the wheel via
+          # maturin's PEP 517 backend, then `maturin develop` builds it again.
+          uv sync --all-extras --no-install-project
           uv run maturin develop --release
           uv run pytest -v
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 1d60b0f57..159b05c81 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -47,7 +47,8 @@ jobs:
           components: rustfmt, clippy
 
       - name: Run tests
-        run: cargo test --no-default-features --features zlob --workspace --exclude fff-nvim
+        # fff-python requires full python o3 machinery which is very slow
+        run: cargo test --no-default-features --features zlob --workspace --exclude fff-nvim --exclude fff-python
 
   stress-test:
     name: Fuzz Tests
diff --git a/Makefile b/Makefile
index 5d8e2beea..c968f9015 100644
--- a/Makefile
+++ b/Makefile
@@ -45,6 +45,11 @@ sync-js-api-check:
 build:
 	cargo build --release --no-default-features --features zlob
 
+# Only the crates the e2e suites load (nvim lua tests + C/bun/node FFI tests),
+# skipping fff-python (pyo3) and fff-mcp (tokio/rmcp) which e2e never touches.
+build-e2e:
+	cargo build --release -p fff-nvim -p fff-c --no-default-features --features zlob
+
 build-c-lib:
 	cargo build --release -p fff-c --no-default-features --features zlob
 
@@ -90,7 +95,7 @@ test-setup:
 	fi
 
 test-rust:
-	cargo test --workspace --no-default-features --features zlob --exclude fff-nvim
+	cargo test --workspace --no-default-features --features zlob --exclude fff-nvim --exclude fff-python
 
 # Watcher rescan harness: asserts that editing, build output, git activity and
 # preview reads all stay on the incremental path instead of re-walking the tree.