diff --git a/.woodpecker.yml b/.woodpecker.yml
index b82dd94..7781a05 100644
--- a/.woodpecker.yml
+++ b/.woodpecker.yml
@@ -9,6 +9,15 @@ steps:
     when:
       - event: pull_request
 
+  cargo_shear:
+    image: *rust_nightly_image
+    commands:
+      - *install_binstall
+      - cargo binstall -y cargo-shear
+      - cargo shear
+    when:
+      - event: pull_request
+
   cargo_clippy:
     image: *rust_image
     environment:
diff --git a/Cargo.toml b/Cargo.toml
index 5ac2d79..53698d8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -93,7 +93,6 @@ tower = { version = "0.4.13", optional = true }
 [dev-dependencies]
 anyhow = "1.0.86"
 axum = { version = "0.7.5", features = ["macros"] }
-axum-extra = { version = "0.9.3", features = ["typed-header"] }
 env_logger = "0.11.3"
 tokio = { version = "1.38.0", features = ["full"] }
 
diff --git a/src/fetch/object_id.rs b/src/fetch/object_id.rs
index d9dcbe2..b6aafc6 100644
--- a/src/fetch/object_id.rs
+++ b/src/fetch/object_id.rs
@@ -360,7 +360,7 @@ const _IMPL_DIESEL_NEW_TYPE_FOR_OBJECT_ID: () = {
     }
 };
 
-/// Shared test code
+/// Internal only
 #[cfg(test)]
 #[allow(clippy::unwrap_used)]
 pub mod tests {
diff --git a/src/http_signatures.rs b/src/http_signatures.rs
index f4f94e1..f30e75c 100644
--- a/src/http_signatures.rs
+++ b/src/http_signatures.rs
@@ -277,7 +277,7 @@ pub(crate) fn verify_body_hash(
     Ok(())
 }
 
-/// Shared test code
+/// Internal only
 #[cfg(test)]
 #[allow(clippy::unwrap_used)]
 pub mod test {
@@ -379,7 +379,7 @@ pub mod test {
         assert_eq!(invalid, Err(Error::ActivityBodyDigestInvalid));
     }
 
-    /// Return hardcoded keypair
+    /// Internal only, return hardcoded keypair for testing
     pub fn test_keypair() -> Keypair {
         let rsa = RsaPrivateKey::from_pkcs1_pem(PRIVATE_KEY).unwrap();
         let pkey = RsaPublicKey::from(&rsa);
diff --git a/src/protocol/verification.rs b/src/protocol/verification.rs
index 18595b9..c6c342a 100644
--- a/src/protocol/verification.rs
+++ b/src/protocol/verification.rs
@@ -1,6 +1,7 @@
 //! Verify that received data is valid
 
-use crate::error::Error;
+use crate::{config::Data, error::Error, fetch::object_id::ObjectId, traits::Object};
+use serde::Deserialize;
 use url::Url;
 
 /// Check that both urls have the same domain. If not, return UrlVerificationError.
@@ -36,3 +37,38 @@ pub fn verify_urls_match(a: &Url, b: &Url) -> Result<(), Error> {
     }
     Ok(())
 }
+
+/// Check that the given ID doesn't match the local domain.
+///
+/// It is important to verify this to avoid local objects from being overwritten. In general
+/// locally created objects should be considered authorative, while incoming federated data
+/// is untrusted. Lack of such a check could allow an attacker to rewrite local posts. It could
+/// also result in an `object.local` field being overwritten with `false` for local objects, resulting in invalid data.
+///
+/// ```
+/// # use activitypub_federation::fetch::object_id::ObjectId;
+/// # use activitypub_federation::config::FederationConfig;
+/// # use activitypub_federation::protocol::verification::verify_is_remote_object;
+/// # use activitypub_federation::traits::tests::{DbConnection, DbUser};
+/// # tokio::runtime::Runtime::new().unwrap().block_on(async {
+/// # let config = FederationConfig::builder().domain("example.com").app_data(DbConnection).build().await?;
+/// # let data = config.to_request_data();
+/// let id = ObjectId::<DbUser>::parse("https://remote.com/u/name")?;
+/// assert!(verify_is_remote_object(&id, &data).is_ok());
+/// # Ok::<(), anyhow::Error>(())
+/// # }).unwrap();
+/// ```
+pub fn verify_is_remote_object<Kind, R: Clone>(
+    id: &ObjectId<Kind>,
+    data: &Data<<Kind as Object>::DataType>,
+) -> Result<(), Error>
+where
+    Kind: Object<DataType = R> + Send + 'static,
+    for<'de2> <Kind as Object>::Kind: Deserialize<'de2>,
+{
+    if id.is_local(data) {
+        Err(Error::UrlVerificationError("Object is not remote"))
+    } else {
+        Ok(())
+    }
+}