@@ -28,6 +28,7 @@ jobs:
             ~/.cargo/registry/cache/
             ~/.cargo/git/db/
             target/
+            tests/fixtures/reusable-app/target/
           key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
           restore-keys: |
             ${{ runner.os }}-cargo-
@@ -49,6 +50,12 @@ jobs:
       - name: Run cargo fmt
         run: cargo fmt --all -- --check
 
+      - name: Run cargo fmt (lifecycle fixtures)
+        run: cargo fmt --manifest-path tests/fixtures/reusable-app/Cargo.toml --all -- --check
+
+      - name: Run cargo clippy (native lifecycle fixtures)
+        run: cargo clippy --locked --manifest-path tests/fixtures/reusable-app/Cargo.toml -p fixture-harness -p fixture-core -p fixture-axum --all-targets -- -D warnings
+
       - name: Run cargo clippy
         run: cargo clippy --workspace --all-targets --all-features -- -D warnings
 
@@ -108,6 +115,7 @@ jobs:
             ~/.cargo/registry/cache/
             ~/.cargo/git/db/
             target/
+            tests/fixtures/reusable-app/target/
           key: ${{ runner.os }}-cargo-${{ matrix.adapter }}-clippy-${{ hashFiles('**/Cargo.lock') }}
           restore-keys: |
             ${{ runner.os }}-cargo-${{ matrix.adapter }}-clippy-
@@ -132,6 +140,10 @@ jobs:
       - name: Clippy ${{ matrix.adapter }} (${{ matrix.features }}) on ${{ matrix.target }}
         run: cargo clippy -p edgezero-adapter-${{ matrix.adapter }} --features "${{ matrix.features }}" --target ${{ matrix.target }} --all-targets -- -D warnings
 
+      - name: Clippy ${{ matrix.adapter }} lifecycle fixture
+        if: matrix.features != 'fastly cli'
+        run: cargo clippy --locked --manifest-path tests/fixtures/reusable-app/Cargo.toml -p fixture-${{ matrix.adapter }} --target ${{ matrix.target }} --all-targets -- -D warnings
+
   format-docs:
     runs-on: ubuntu-latest
     defaults:
 
@@ -29,6 +29,7 @@ jobs:
             ~/.cargo/registry/cache/
             ~/.cargo/git/db/
             target/
+            tests/fixtures/reusable-app/target/
           key: ${{ runner.os }}-cargo-test-${{ hashFiles('**/Cargo.lock') }}
           restore-keys: |
             ${{ runner.os }}-cargo-test-
@@ -65,6 +66,13 @@ jobs:
       - name: Nested AppConfig checker tests
         run: cargo test -p edgezero-cli --features nested-app-config-check --bin check_no_nested_app_config
 
+      - name: Lifecycle fixture host tests
+        run: |
+          cargo test --locked --manifest-path tests/fixtures/reusable-app/Cargo.toml -p fixture-harness -p fixture-core
+
+      - name: Check Axum lifecycle fixture
+        run: cargo check --locked --manifest-path tests/fixtures/reusable-app/Cargo.toml -p fixture-axum
+
       - name: Run workspace tests
         run: cargo test --workspace --all-targets
 
@@ -133,6 +141,7 @@ jobs:
             ~/.cargo/git/db/
             ~/.wasmtime/bin/
             target/
+            tests/fixtures/reusable-app/target/
           key: ${{ runner.os }}-cargo-${{ matrix.adapter }}-${{ hashFiles('**/Cargo.lock', '.tool-versions') }}
           restore-keys: |
             ${{ runner.os }}-cargo-${{ matrix.adapter }}-
@@ -247,5 +256,22 @@ jobs:
           ${{ matrix.runner_env }}: ${{ matrix.runner_value }}
         run: cargo test -p edgezero-adapter-fastly --features fastly --target wasm32-wasip1 --lib
 
+      - name: Fastly reusable HTTP smoke
+        if: matrix.adapter == 'fastly'
+        run: ./scripts/smoke_test_reusable_app.sh --adapter fastly --suite smoke
+
+      - name: Preserve Fastly lifecycle evidence
+        if: always() && matrix.adapter == 'fastly'
+        uses: actions/upload-artifact@v4
+        with:
+          name: fastly-lifecycle-evidence
+          path: tests/fixtures/reusable-app/.runs/
+          include-hidden-files: true
+          if-no-files-found: ignore
+          retention-days: 7
+
       - name: Check ${{ matrix.adapter }} wasm target
         run: cargo check -p edgezero-adapter-${{ matrix.adapter }} --features ${{ matrix.adapter }} --target ${{ matrix.target }}
+
+      - name: Check ${{ matrix.adapter }} lifecycle fixture
+        run: cargo check --locked --manifest-path tests/fixtures/reusable-app/Cargo.toml -p fixture-${{ matrix.adapter }} --target ${{ matrix.target }} --all-targets
@@ -17,11 +17,13 @@ pub mod proxy;
 pub mod request;
 #[cfg(all(feature = "cloudflare", target_arch = "wasm32"))]
 pub mod response;
+#[cfg(any(test, all(feature = "cloudflare", target_arch = "wasm32")))]
+mod response_headers;
 #[cfg(all(feature = "cloudflare", target_arch = "wasm32"))]
 pub mod secret_store;
 
 #[cfg(all(feature = "cloudflare", target_arch = "wasm32"))]
-use edgezero_core::app::{Hooks, StoresMetadata};
+use edgezero_core::app::{App, Hooks, StoresMetadata};
 #[cfg(all(feature = "cloudflare", target_arch = "wasm32"))]
 use edgezero_core::env_config::EnvConfig;
 #[cfg(all(feature = "cloudflare", target_arch = "wasm32"))]
@@ -106,11 +108,32 @@ pub async fn run_app<A: Hooks>(
     if !A::owns_logging() {
         drop(init_logger());
     }
+    let app = A::build_app();
+    dispatch_app::<A>(&app, req, env, ctx).await
+}
+
+#[cfg(all(feature = "cloudflare", target_arch = "wasm32"))]
+/// Dispatch a caller-owned app using `A::stores()` for fresh request bindings.
+///
+/// This does not build or cache an app or install logging. The caller must pass
+/// an app built from `A`; `App` erases its construction type, so this pairing
+/// remains a caller precondition. Retain only application-owned values and keep
+/// native handles and pending work request-local. Shared state must support
+/// overlapping invocations.
+///
+/// # Errors
+/// Returns conversion or dispatch errors from the existing adapter boundary.
+#[inline]
+pub async fn dispatch_app<A: Hooks>(
+    app: &App,
+    req: Request,
+    env: Env,
+    ctx: Context,
+) -> Result<Response, WorkerError> {
     let stores = A::stores();
     let env_config = env_config_from_worker(&env, stores);
-    let app = A::build_app();
     request::dispatch_with_registries(
-        &app,
+        app,
         req,
         env,
         ctx,
 
@@ -1,3 +1,4 @@
+use crate::response_headers::copy_headers;
 use edgezero_core::body::Body;
 use edgezero_core::error::EdgeError;
 use edgezero_core::http::Response;
@@ -9,8 +10,8 @@ use worker::{Error as WorkerError, Response as CfResponse};
 /// # Errors
 /// Returns an [`EdgeError`] if the response body cannot be materialised
 /// into a Workers response (empty body construction failure, byte body
-/// conversion failure, stream adoption failure) or if any response
-/// header is non-UTF-8 and the Workers header table rejects it.
+/// conversion failure, stream adoption failure) or the Workers header table
+/// rejects a text header. Non-text header values are skipped.
 #[inline]
 pub fn from_core_response(response: Response) -> Result<CfResponse, EdgeError> {
     let (parts, body) = response.into_parts();
@@ -33,13 +34,14 @@ pub fn from_core_response(response: Response) -> Result<CfResponse, EdgeError> {
 
     let mut cf_response = body_response.with_status(parts.status.as_u16());
     let headers = cf_response.headers_mut();
-    for (name, value) in &parts.headers {
-        if let Ok(value_str) = value.to_str() {
-            headers
-                .set(name.as_str(), value_str)
-                .map_err(EdgeError::internal)?;
+    copy_headers(&parts.headers, |name, value, replace| {
+        if replace {
+            headers.set(name, value)
+        } else {
+            headers.append(name, value)
         }
-    }
+    })
+    .map_err(EdgeError::internal)?;
     Ok(cf_response)
 }
 
 
@@ -0,0 +1,94 @@
+use edgezero_core::http::HeaderMap;
+
+/// Replace a body-generated default with the first valid application value,
+/// then append additional values. Non-text values retain the adapter's skip policy.
+pub(crate) fn copy_headers<E, F>(headers: &HeaderMap, mut write: F) -> Result<(), E>
+where
+    F: FnMut(&str, &str, bool) -> Result<(), E>,
+{
+    for name in headers.keys() {
+        let mut replace = true;
+        for value in headers.get_all(name) {
+            if let Ok(text) = value.to_str() {
+                write(name.as_str(), text, replace)?;
+                replace = false;
+            }
+        }
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::copy_headers;
+    use edgezero_core::http::{HeaderMap, HeaderName, HeaderValue};
+
+    #[test]
+    fn replaces_defaults_and_preserves_separate_cookies() {
+        let mut source = HeaderMap::new();
+        source.append("set-cookie", HeaderValue::from_static("first=1; Path=/"));
+        source.append("set-cookie", HeaderValue::from_static("second=2; Path=/"));
+        source.insert("content-type", HeaderValue::from_static("text/plain"));
+        let mut target = HeaderMap::new();
+        target.insert(
+            "content-type",
+            HeaderValue::from_static("application/octet-stream"),
+        );
+        target.insert("set-cookie", HeaderValue::from_static("default=discard"));
+        copy_headers(&source, |name, value, replace| {
+            let parsed_name = name.parse::<HeaderName>().unwrap();
+            let parsed_value = HeaderValue::from_str(value).unwrap();
+            if replace {
+                target.insert(parsed_name, parsed_value);
+            } else {
+                target.append(parsed_name, parsed_value);
+            }
+            Ok::<_, ()>(())
+        })
+        .unwrap();
+        assert_eq!(target, source);
+        assert_eq!(target.get_all("set-cookie").iter().count(), 2);
+    }
+
+    #[test]
+    fn first_valid_value_replaces_even_after_invalid_value() {
+        let mut source = HeaderMap::new();
+        source.append("x-test", HeaderValue::from_bytes(b"\xff").unwrap());
+        source.append("x-test", HeaderValue::from_static("valid"));
+        source.append("x-test", HeaderValue::from_static("next"));
+        let mut writes = Vec::new();
+        copy_headers(&source, |_, value, replace| {
+            writes.push((value.to_owned(), replace));
+            Ok::<_, ()>(())
+        })
+        .unwrap();
+        assert_eq!(
+            writes,
+            [("valid".to_owned(), true), ("next".to_owned(), false)]
+        );
+    }
+
+    #[test]
+    fn invalid_only_values_do_not_touch_generated_defaults() {
+        let mut source = HeaderMap::new();
+        source.append("x-test", HeaderValue::from_bytes(b"\xff").unwrap());
+        copy_headers(&source, |_, _, _| -> Result<(), ()> {
+            panic!("invalid text must not reach the sink")
+        })
+        .unwrap();
+    }
+
+    #[test]
+    fn stops_at_sink_error() {
+        let mut source = HeaderMap::new();
+        source.append("set-cookie", HeaderValue::from_static("first=1"));
+        source.append("set-cookie", HeaderValue::from_static("second=2"));
+        let mut calls = 0_u32;
+        let result = copy_headers(&source, |_, _, _| {
+            calls += 1;
+            Err("header rejected")
+        });
+        assert_eq!(result, Err("header rejected"));
+        assert_eq!(calls, 1);
+    }
+}
@@ -20,7 +20,7 @@ mod tests {
     use edgezero_adapter_cloudflare::context::CloudflareRequestContext;
     use edgezero_adapter_cloudflare::request::{CloudflareService, into_core_request};
     use edgezero_adapter_cloudflare::response::from_core_response;
-    use edgezero_core::app::App;
+    use edgezero_core::app::{App, Hooks};
     use edgezero_core::body::Body;
     use edgezero_core::config_store::{ConfigStore, ConfigStoreError, ConfigStoreHandle};
     use edgezero_core::context::RequestContext;
@@ -150,6 +150,32 @@ mod tests {
         (env, Context::new(js_context))
     }
 
+    #[wasm_bindgen_test]
+    async fn dispatch_app_reuses_router_with_fresh_request_bodies() {
+        struct TestApp;
+        // This fixture deliberately exercises the default Hooks metadata.
+        #[expect(
+            clippy::missing_trait_methods,
+            reason = "exercise default Hooks metadata and construction"
+        )]
+        impl Hooks for TestApp {
+            fn routes() -> RouterService {
+                build_test_app().router().clone()
+            }
+        }
+        let app = TestApp::build_app();
+        for body in [b"first".as_slice(), b"second".as_slice()] {
+            let (env, ctx) = test_env_ctx();
+            let request = cf_request(CfMethod::Post, "/mirror", Some(body));
+            let mut response =
+                edgezero_adapter_cloudflare::dispatch_app::<TestApp>(&app, request, env, ctx)
+                    .await
+                    .expect("prebuilt dispatch response");
+            assert_eq!(response.status_code(), 200);
+            assert_eq!(response.bytes().await.expect("response bytes"), body);
+        }
+    }
+
     #[wasm_bindgen_test]
     async fn dispatch_passes_request_body_to_handlers() {
         let app = build_test_app();