diff --git a/codex-rs/core/src/context/contextual_user_message_tests.rs b/codex-rs/core/src/context/contextual_user_message_tests.rs
index 9ff8eb55da..a4ccbbd738 100644
--- a/codex-rs/core/src/context/contextual_user_message_tests.rs
+++ b/codex-rs/core/src/context/contextual_user_message_tests.rs
@@ -1,6 +1,5 @@
 use super::*;
 use crate::context::ContextualUserFragment;
-use crate::context::ExtensionContextTag;
 use crate::context::SubagentNotification;
 use codex_protocol::items::HookPromptFragment;
 use codex_protocol::items::build_hook_prompt_message;
@@ -21,15 +20,6 @@ fn detects_extension_context_fragment() {
     }));
 }
 
-#[test]
-fn detects_goal_extension_context_fragment() {
-    let text = ExtensionContext::with_tag(ExtensionContextTag::GOAL, "hidden goal prompt").render();
-
-    assert!(is_contextual_user_fragment(&ContentItem::InputText {
-        text
-    }));
-}
-
 #[test]
 fn detects_agents_instructions_fragment() {
     assert!(is_contextual_user_fragment(&ContentItem::InputText {
diff --git a/codex-rs/core/src/context/extension_context.rs b/codex-rs/core/src/context/extension_context.rs
index 972f1ffa2b..15e72191a0 100644
--- a/codex-rs/core/src/context/extension_context.rs
+++ b/codex-rs/core/src/context/extension_context.rs
@@ -1,51 +1,23 @@
 //! Hidden user-context wrappers owned by extensions.
 //!
-//! Extensions can use one of these host-recognized tags when they need hidden
-//! model-visible context to survive history filtering without teaching core
-//! about the extension's domain concepts.
+//! Extensions can use this host-recognized tag when they need hidden
+//! model-visible context to survive history filtering.
 
 use super::ContextualUserFragment;
 use super::fragment::matches_marked_text;
 
-/// Host-recognized marker pair for extension-owned hidden context.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct ExtensionContextTag {
-    start_marker: &'static str,
-    end_marker: &'static str,
-}
-
-impl ExtensionContextTag {
-    pub const DEFAULT: Self = Self::new("<extension_context>", "</extension_context>");
-    pub const GOAL: Self = Self::new("<goal_context>", "</goal_context>");
-
-    const fn new(start_marker: &'static str, end_marker: &'static str) -> Self {
-        Self {
-            start_marker,
-            end_marker,
-        }
-    }
-}
-
-const EXTENSION_CONTEXT_TAGS: &[ExtensionContextTag] =
-    &[ExtensionContextTag::DEFAULT, ExtensionContextTag::GOAL];
+const START_MARKER: &str = "<extension_context>";
+const END_MARKER: &str = "</extension_context>";
 
 /// Hidden user-context fragment for extension-owned steering prompts.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ExtensionContext {
-    tag: ExtensionContextTag,
     body: String,
 }
 
 impl ExtensionContext {
     pub fn new(body: impl Into<String>) -> Self {
-        Self::with_tag(ExtensionContextTag::DEFAULT, body)
-    }
-
-    pub fn with_tag(tag: ExtensionContextTag, body: impl Into<String>) -> Self {
-        Self {
-            tag,
-            body: body.into(),
-        }
+        Self { body: body.into() }
     }
 }
 
@@ -55,20 +27,15 @@ impl ContextualUserFragment for ExtensionContext {
     }
 
     fn markers(&self) -> (&'static str, &'static str) {
-        (self.tag.start_marker, self.tag.end_marker)
+        (START_MARKER, END_MARKER)
     }
 
     fn type_markers() -> (&'static str, &'static str) {
-        (
-            ExtensionContextTag::DEFAULT.start_marker,
-            ExtensionContextTag::DEFAULT.end_marker,
-        )
+        (START_MARKER, END_MARKER)
     }
 
     fn matches_text(text: &str) -> bool {
-        EXTENSION_CONTEXT_TAGS
-            .iter()
-            .any(|tag| matches_marked_text(tag.start_marker, tag.end_marker, text))
+        matches_marked_text(START_MARKER, END_MARKER, text)
     }
 
     fn body(&self) -> String {
diff --git a/codex-rs/core/src/context/mod.rs b/codex-rs/core/src/context/mod.rs
index 70dac08b80..5ad1a8711e 100644
--- a/codex-rs/core/src/context/mod.rs
+++ b/codex-rs/core/src/context/mod.rs
@@ -39,7 +39,6 @@ pub(crate) use contextual_user_message::is_contextual_user_fragment;
 pub(crate) use contextual_user_message::parse_visible_hook_prompt_message;
 pub(crate) use environment_context::EnvironmentContext;
 pub use extension_context::ExtensionContext;
-pub use extension_context::ExtensionContextTag;
 pub use fragment::ContextualUserFragment;
 pub(crate) use fragment::FragmentRegistration;
 pub(crate) use fragment::FragmentRegistrationProxy;
diff --git a/codex-rs/core/src/tasks/idle_extension.rs b/codex-rs/core/src/tasks/idle_extension.rs
index e570a7fbba..eadc25ae5d 100644
--- a/codex-rs/core/src/tasks/idle_extension.rs
+++ b/codex-rs/core/src/tasks/idle_extension.rs
@@ -228,8 +228,6 @@ fn idle_extension_input(prompt: String) -> TurnInput {
 
 #[cfg(test)]
 mod tests {
-    use crate::context::ExtensionContextTag;
-
     use super::*;
 
     #[test]
@@ -240,7 +238,7 @@ mod tests {
         );
         let original_len = prompt.len();
 
-        let prompt = ExtensionContext::with_tag(ExtensionContextTag::GOAL, prompt).render();
+        let prompt = ExtensionContext::new(prompt).render();
         let TurnInput::ResponseInputItem(ResponseInputItem::Message { content, .. }) =
             idle_extension_input(prompt)
         else {
@@ -250,7 +248,7 @@ mod tests {
             panic!("expected one text content item");
         };
 
-        assert!(text.starts_with("<goal_context>"));
+        assert!(text.starts_with("<extension_context>"));
         assert!(text.contains("start"));
         assert!(text.contains("end"));
         assert!(text.len() < original_len);
diff --git a/codex-rs/ext/goal/src/steering.rs b/codex-rs/ext/goal/src/steering.rs
index 0e7d493c7f..92a05afb80 100644
--- a/codex-rs/ext/goal/src/steering.rs
+++ b/codex-rs/ext/goal/src/steering.rs
@@ -1,6 +1,5 @@
 use codex_core::context::ContextualUserFragment;
 use codex_core::context::ExtensionContext;
-use codex_core::context::ExtensionContextTag;
 use codex_extension_api::ThreadIdleRequest;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::protocol::ThreadGoal;
@@ -47,21 +46,19 @@ fn render_embedded_template<const N: usize>(
 }
 
 pub(crate) fn budget_limit_steering_item(goal: &ThreadGoal) -> ResponseInputItem {
-    goal_context_input_item(budget_limit_prompt(goal))
+    extension_context_input_item(budget_limit_prompt(goal))
 }
 
 pub(crate) fn continuation_steering_request(goal: &ThreadGoal) -> ThreadIdleRequest {
-    ThreadIdleRequest::new(
-        ExtensionContext::with_tag(ExtensionContextTag::GOAL, continuation_prompt(goal)).render(),
-    )
+    ThreadIdleRequest::new(ExtensionContext::new(continuation_prompt(goal)).render())
 }
 
 pub(crate) fn objective_updated_steering_item(goal: &ThreadGoal) -> ResponseInputItem {
-    goal_context_input_item(objective_updated_prompt(goal))
+    extension_context_input_item(objective_updated_prompt(goal))
 }
 
-fn goal_context_input_item(prompt: String) -> ResponseInputItem {
-    ExtensionContext::with_tag(ExtensionContextTag::GOAL, prompt).into_response_input_item()
+fn extension_context_input_item(prompt: String) -> ResponseInputItem {
+    ExtensionContext::new(prompt).into_response_input_item()
 }
 
 fn continuation_prompt(goal: &ThreadGoal) -> String {
diff --git a/codex-rs/ext/goal/tests/goal_extension_backend.rs b/codex-rs/ext/goal/tests/goal_extension_backend.rs
index 438c0d0cfb..c620c94399 100644
--- a/codex-rs/ext/goal/tests/goal_extension_backend.rs
+++ b/codex-rs/ext/goal/tests/goal_extension_backend.rs
@@ -507,14 +507,14 @@ async fn thread_idle_hook_requests_hidden_goal_continuation() -> anyhow::Result<
         .ok_or_else(|| anyhow::anyhow!("active goal should request idle continuation"))?;
 
     assert!(request.validation_key.is_some());
-    assert!(request.prompt.starts_with("<goal_context>"));
+    assert!(request.prompt.starts_with("<extension_context>"));
     assert!(
         request
             .prompt
             .contains("Continue working toward the active thread goal.")
     );
     assert!(request.prompt.contains("Completion audit:"));
-    assert!(request.prompt.ends_with("</goal_context>"));
+    assert!(request.prompt.ends_with("</extension_context>"));
     assert!(
         harness
             .should_start_idle_turn(ModeKind::Default, &request)