diff --git a/README.md b/README.md
index bb59e64..a7d798d 100644
--- a/README.md
+++ b/README.md
@@ -218,6 +218,12 @@ GitHub-linked releases. Clients use it to skip incompatible versions during
 unversioned installs and to reject incompatible explicit or locked installs
 before replacing local package files.
 
+For a GitHub-linked package the requirement is read from `sema.toml` **at each
+tag**, so every release records the requirement it was published with and
+editing the field does not rewrite past releases. A tag whose `sema.toml` is
+missing or unreadable records no requirement; a tag whose `sema.toml` parses but
+holds an invalid requirement is reported in the package's sync log.
+
 ### Source Locking
 
 A package is either **CLI-uploaded** or **GitHub-linked**, never both. Once a package is linked to a repo, it cannot be published via `sema publish`, and vice versa.
diff --git a/src/api/github.rs b/src/api/github.rs
index 0dba41e..0c7d2af 100644
--- a/src/api/github.rs
+++ b/src/api/github.rs
@@ -123,18 +123,14 @@ pub async fn link(
     let mut imported = 0u32;
     let mut errors = Vec::new();
 
+    let access = github_sync::RepoAccess {
+        client: &client,
+        token: &token,
+        owner: &owner_name,
+        repo: &repo,
+    };
     for (tag_name, version) in &tags {
-        match github_sync::sync_tag(
-            &state.db,
-            &owner_name,
-            &repo,
-            tag_name,
-            version,
-            package_id,
-            manifest.sema_version_req.as_deref(),
-        )
-        .await
-        {
+        match github_sync::sync_tag(&state.db, &access, tag_name, version, package_id).await {
             Ok(true) => imported += 1,
             Ok(false) => {}
             Err(e) => {
@@ -210,18 +206,14 @@ pub async fn sync(
     };
 
     let mut imported = 0u32;
+    let access = github_sync::RepoAccess {
+        client: &client,
+        token: &token,
+        owner: &owner_name,
+        repo: &repo,
+    };
     for (tag_name, version) in &tags {
-        match github_sync::sync_tag(
-            &state.db,
-            &owner_name,
-            &repo,
-            tag_name,
-            version,
-            package_id,
-            None,
-        )
-        .await
-        {
+        match github_sync::sync_tag(&state.db, &access, tag_name, version, package_id).await {
             Ok(true) => imported += 1,
             Ok(false) => {}
             Err(e) => {
@@ -339,17 +331,31 @@ pub async fn webhook(
     let (owner_name, repo) = github_sync::parse_github_url(repo_full_name)
         .ok_or_else(|| ApiError::bad_request("Invalid repo name"))?;
 
-    match github_sync::sync_tag(
-        &state.db,
-        &owner_name,
-        &repo,
-        tag_name,
-        &version,
-        package_id,
-        None,
-    )
-    .await
-    {
+    // The webhook has no authenticated user, so read the repo with an owner's stored
+    // GitHub token. Without it the tag's sema_version_req cannot be read at all.
+    let owner_user_id = dal::owners::first_user_id(&state.db, package_id)
+        .await
+        .ok()
+        .flatten()
+        .ok_or_else(|| ApiError::forbidden("Package has no owner"))?;
+    let token =
+        github_sync::get_github_token(&state.db, owner_user_id, &state.config.oauth_token_key)
+            .await
+            .ok_or_else(|| {
+                ApiError::new(
+                    StatusCode::BAD_GATEWAY,
+                    "Package owner has no active GitHub connection",
+                )
+            })?;
+    let client = reqwest::Client::new();
+    let access = github_sync::RepoAccess {
+        client: &client,
+        token: &token,
+        owner: &owner_name,
+        repo: &repo,
+    };
+
+    match github_sync::sync_tag(&state.db, &access, tag_name, &version, package_id).await {
         Ok(true) => {
             tracing::info!("Webhook: synced {repo_full_name} tag {tag_name} as {version}");
             crate::audit::log(
diff --git a/src/dal/owners.rs b/src/dal/owners.rs
index f6e4981..8e26278 100644
--- a/src/dal/owners.rs
+++ b/src/dal/owners.rs
@@ -40,6 +40,26 @@ pub async fn package_id_if_owner<C: ConnectionTrait>(
     Ok(row.and_then(|r| r.try_get("", "id").ok()))
 }
 
+/// The lowest owner user id for `package_id`, if the package has an owner.
+///
+/// The webhook runs with no authenticated user, so it needs an owner's stored GitHub
+/// token to read the repo. Ordering by id keeps the choice stable as owners change.
+pub async fn first_user_id<C: ConnectionTrait>(
+    db: &C,
+    package_id: i64,
+) -> Result<Option<i64>, DbErr> {
+    let row = db
+        .query_one(crate::db::stmt(
+            db.get_database_backend(),
+            r#"SELECT o.user_id FROM owners o
+               WHERE o.package_id = ?
+               ORDER BY o.user_id ASC"#,
+            [package_id.into()],
+        ))
+        .await?;
+    Ok(row.and_then(|r| r.try_get("", "user_id").ok()))
+}
+
 /// Usernames of every owner of `package_id`.
 pub async fn list_usernames<C: ConnectionTrait>(
     db: &C,
diff --git a/src/github_sync.rs b/src/github_sync.rs
index 07884ae..916e1bc 100644
--- a/src/github_sync.rs
+++ b/src/github_sync.rs
@@ -169,19 +169,87 @@ pub async fn list_semver_tags(
     Ok(tags)
 }
 
+/// Everything needed to read one GitHub repository.
+///
+/// Grouping these keeps the owner, repo, and tag from being transposed at a call site
+/// where they are all `&str`.
+pub struct RepoAccess<'a> {
+    pub client: &'a reqwest::Client,
+    pub token: &'a str,
+    pub owner: &'a str,
+    pub repo: &'a str,
+}
+
+/// Read `[package].sema_version_req` from `sema.toml` at one tag.
+///
+/// A tag with no readable `sema.toml` declares no requirement — tags older than the
+/// manifest are normal, and a fetch failure must not block the import. A manifest that
+/// IS readable but holds an invalid requirement is an error, so the maintainer sees it
+/// in the sync log instead of the release silently losing its constraint.
+async fn fetch_tag_sema_version_req(
+    access: &RepoAccess<'_>,
+    tag_name: &str,
+) -> Result<Option<String>, String> {
+    let RepoAccess {
+        client,
+        token,
+        owner,
+        repo,
+    } = access;
+    let url = format!("https://api.github.com/repos/{owner}/{repo}/contents/sema.toml");
+    let resp = client
+        .get(url)
+        // `.query` percent-encodes, so a tag like `release/1.0` stays one parameter.
+        .query(&[("ref", tag_name)])
+        .header("Authorization", format!("Bearer {token}"))
+        .header("User-Agent", "sema-pkg")
+        .header("Accept", "application/vnd.github.raw+json")
+        .send()
+        .await;
+    let Ok(resp) = resp else {
+        return Ok(None);
+    };
+    if !resp.status().is_success() {
+        return Ok(None);
+    }
+    let Ok(content) = resp.text().await else {
+        return Ok(None);
+    };
+    tag_sema_version_req(&content, tag_name)
+}
+
+/// Extract and validate `[package].sema_version_req` from one tag's `sema.toml`.
+///
+/// An unparsable manifest declares no requirement: `sema.toml` is not required to be
+/// valid TOML at every historic tag, and refusing the tag would block the import. A
+/// manifest that parses but holds a bad requirement is an error, so the maintainer sees
+/// it instead of the release silently losing its constraint.
+fn tag_sema_version_req(content: &str, tag_name: &str) -> Result<Option<String>, String> {
+    let Ok(document) = toml::from_str::<toml::Value>(content) else {
+        return Ok(None);
+    };
+    let Some(value) = document
+        .get("package")
+        .and_then(|package| package.get("sema_version_req"))
+    else {
+        return Ok(None);
+    };
+    let requirement = value
+        .as_str()
+        .ok_or_else(|| format!("{tag_name}: sema_version_req must be a string"))?;
+    validate_sema_version_req(Some(requirement)).map_err(|error| format!("{tag_name}: {error}"))
+}
+
 /// Sync a single tag: store metadata and GitHub tarball URL (no blob download).
 /// Returns Ok(true) if version was created, Ok(false) if it already existed.
 pub async fn sync_tag(
     db: &Db,
-    owner: &str,
-    repo: &str,
+    access: &RepoAccess<'_>,
     tag_name: &str,
     version: &semver::Version,
     package_id: i64,
-    sema_version_req: Option<&str>,
 ) -> Result<bool, String> {
     let version_str = version.to_string();
-    let sema_version_req = validate_sema_version_req(sema_version_req)?;
 
     // Check if version already exists
     let exists = crate::dal::versions::exists(db, package_id, &version_str)
@@ -192,6 +260,11 @@ pub async fn sync_tag(
         return Ok(false);
     }
 
+    // Read the requirement from the manifest at this tag, not from the default branch:
+    // each release states its own, and editing the field must not rewrite past releases.
+    let sema_version_req = fetch_tag_sema_version_req(access, tag_name).await?;
+
+    let (owner, repo) = (access.owner, access.repo);
     let tarball_url = format!("https://api.github.com/repos/{owner}/{repo}/tarball/{tag_name}");
 
     crate::dal::versions::create_github_version(
@@ -507,6 +580,44 @@ mod manifest_tests {
         assert_eq!(error, "sema_version_req must be a string");
     }
 
+    #[test]
+    fn tag_manifest_reads_the_requirement_at_that_tag() {
+        let content = "[package]\nname = \"policies\"\nsema_version_req = \"  >=1.34.0  \"\n";
+        assert_eq!(
+            tag_sema_version_req(content, "v1.0.0").unwrap(),
+            Some(">=1.34.0".to_string())
+        );
+    }
+
+    #[test]
+    fn tag_manifest_without_a_requirement_is_absent_not_an_error() {
+        // A tag older than the field, or older than sema.toml itself, must still import.
+        assert_eq!(
+            tag_sema_version_req("[package]\nname = \"policies\"\n", "v0.1.0").unwrap(),
+            None
+        );
+        assert_eq!(tag_sema_version_req("", "v0.1.0").unwrap(), None);
+        assert_eq!(
+            tag_sema_version_req("not : valid : toml", "v0.1.0").unwrap(),
+            None
+        );
+    }
+
+    #[test]
+    fn tag_manifest_with_a_bad_requirement_names_the_tag() {
+        let error = tag_sema_version_req(
+            "[package]\nsema_version_req = \"not a requirement\"\n",
+            "v1.2.3",
+        )
+        .unwrap_err();
+        assert!(error.starts_with("v1.2.3: "), "{error}");
+        assert!(error.contains("Invalid sema_version_req"), "{error}");
+
+        let error =
+            tag_sema_version_req("[package]\nsema_version_req = 34\n", "v1.2.3").unwrap_err();
+        assert_eq!(error, "v1.2.3: sema_version_req must be a string");
+    }
+
     #[test]
     fn validator_treats_blank_as_absent_and_limits_length() {
         assert_eq!(validate_sema_version_req(Some("  ")).unwrap(), None);
diff --git a/tests/integration_test.rs b/tests/integration_test.rs
index 977d3ff..55eac2d 100644
--- a/tests/integration_test.rs
+++ b/tests/integration_test.rs
@@ -248,6 +248,81 @@ async fn test_publish_and_get_package() {
     assert_eq!(body["owners"][0], "publisher");
 }
 
+#[tokio::test]
+async fn test_sema_version_req_survives_publish_and_is_served_under_that_key() {
+    // The `sema pkg` client reads versions[].sema_version_req from this response and
+    // refuses an incompatible install. If the key is renamed, dropped, or left out of
+    // the query, the client silently stops enforcing, so pin the name and the value.
+    let (app, _dir) = test_app().await;
+    let session = register_user(app.clone(), "reqpub", "req@example.com").await;
+    let token = create_api_token(app.clone(), &session, "req-token").await;
+
+    let meta = serde_json::json!({
+        "description": "requirement carrier",
+        "sema_version_req": "  >=1.34.0  ",
+    });
+    let res = publish_package_full(
+        app.clone(),
+        &token,
+        "req-pkg",
+        "1.0.0",
+        &gzip(b"tarball"),
+        &serde_json::to_string(&meta).unwrap(),
+    )
+    .await;
+    assert_eq!(res.status(), StatusCode::CREATED);
+
+    let res = app
+        .clone()
+        .oneshot(
+            Request::builder()
+                .uri("/api/v1/packages/req-pkg")
+                .body(Body::empty())
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(res.status(), StatusCode::OK);
+    let body = body_json(res).await;
+    // Stored normalized (trimmed), served under exactly this key.
+    assert_eq!(body["versions"][0]["sema_version_req"], ">=1.34.0");
+}
+
+#[tokio::test]
+async fn test_publish_rejects_an_invalid_sema_version_req() {
+    let (app, _dir) = test_app().await;
+    let session = register_user(app.clone(), "badreq", "badreq@example.com").await;
+    let token = create_api_token(app.clone(), &session, "badreq-token").await;
+
+    let meta = serde_json::json!({
+        "description": "bad requirement",
+        "sema_version_req": "not a requirement",
+    });
+    let res = publish_package_full(
+        app.clone(),
+        &token,
+        "badreq-pkg",
+        "1.0.0",
+        &gzip(b"tarball"),
+        &serde_json::to_string(&meta).unwrap(),
+    )
+    .await;
+    assert_eq!(res.status(), StatusCode::BAD_REQUEST);
+
+    // The rejected publish must not have created the package.
+    let res = app
+        .clone()
+        .oneshot(
+            Request::builder()
+                .uri("/api/v1/packages/badreq-pkg")
+                .body(Body::empty())
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(res.status(), StatusCode::NOT_FOUND);
+}
+
 #[tokio::test]
 async fn test_publish_duplicate_version() {
     let (app, _dir) = test_app().await;