Handle standalone tool outputs as external context (#39791)

## What changed

- Treat standalone `function_call_output` items without a `call_id` as external context, including items injected into new and forked threads, and mark the thread memory mode polluted when `memories.disable_on_external_context` is enabled.
- Include these outputs in guardian transcripts with their namespaced tool name and a placeholder for non-text content.
- Allow image generation to reuse images from standalone and otherwise unpaired function or custom-tool outputs.

## Testing

- Cover injected thread items, external-context detection, guardian transcript rendering, and recent-image selection.

GitOrigin-RevId: ca4e8c16a4b731e1256a5956908d00f785b4feb1

codex-rs/app-server/tests/suite/v2/thread_inject_items.rs

@@ -13,10 +13,13 @@ use codex_app_server_protocol::TurnStartResponse;
 use codex_app_server_protocol::UserInput as V2UserInput;
 use codex_core::RolloutRecorder;
 use codex_features::Feature;
+use codex_protocol::ThreadId;
 use codex_protocol::models::ContentItem;
 use codex_protocol::models::ResponseItem;
 use codex_rollout::InitialHistory;
 use codex_rollout::RolloutItem;
+use codex_state::StateRuntime;
+use codex_utils_absolute_path::test_support::PathExt;
 use core_test_support::responses;
 use core_test_support::responses::strip_response_item_id;
 use core_test_support::responses::strip_response_item_ids_from_json;
@@ -40,8 +43,15 @@ async fn thread_inject_items_adds_raw_response_items_to_thread_history() -> Resu
 
     let codex_home = TempDir::new()?;
     MockResponsesConfig::new(&server.uri())
+        .enable_feature(Feature::Sqlite)
         .enable_feature(Feature::RetainClientDeveloperMessages)
+        .with_extra_config("[memories]\ndisable_on_external_context = true")
         .write(codex_home.path())?;
+    let state_db = StateRuntime::init(
+        codex_state::SqliteConfig::new_for_testing(codex_home.path().abs()),
+        "mock_provider".into(),
+    )
+    .await?;
 
     let mut mcp = TestAppServer::builder()
         .with_codex_home(codex_home.path())
@@ -100,6 +110,13 @@ async fn thread_inject_items_adds_raw_response_items_to_thread_history() -> Resu
         .await?;
     let _response: ThreadInjectItemsResponse =
         timeout(DEFAULT_READ_TIMEOUT, mcp.read_response(inject_req)).await??;
+    assert_eq!(
+        state_db
+            .get_thread_memory_mode(ThreadId::from_string(&thread.id)?)
+            .await?
+            .as_deref(),
+        Some("polluted")
+    );
 
     let rollout_path = thread.path.as_ref().context("thread path missing")?;
     let history = RolloutRecorder::get_rollout_history(rollout_path).await?;

codex-rs/core/src/guardian/prompt.rs

@@ -595,6 +595,26 @@ pub(crate) fn collect_guardian_transcript_entries<'a>(
                 };
                 non_empty_entry(kind, text)
             }),
+            ResponseItem::FunctionCallOutput {
+                call_id: None,
+                name: Some(name),
+                namespace,
+                output,
+                ..
+            } => {
+                let text = output
+                    .body
+                    .to_text()
+                    .unwrap_or_else(|| "[non-text output]".into());
+                let name = match namespace {
+                    Some(namespace) => format!("{namespace}.{name}"),
+                    None => name.to_string(),
+                };
+                non_empty_entry(
+                    GuardianTranscriptEntryKind::Tool(format!("tool {name} result")),
+                    text,
+                )
+            }
             _ => None,
         };
 

codex-rs/core/src/guardian/tests.rs

@@ -40,6 +40,7 @@ use codex_protocol::ThreadId;
 use codex_protocol::approvals::NetworkApprovalProtocol;
 use codex_protocol::config_types::ApprovalsReviewer;
 use codex_protocol::models::ContentItem;
+use codex_protocol::models::FunctionCallOutputContentItem;
 use codex_protocol::models::PermissionProfile;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::openai_models::ModelsResponse;
@@ -1046,6 +1047,44 @@ fn collect_guardian_transcript_entries_includes_recent_tool_calls_and_output() {
     ));
 }
 
+#[test]
+fn collect_guardian_transcript_entries_preserves_named_unpaired_tool_sources() {
+    let mut items = vec![ResponseItem::FunctionCallOutput {
+        id: None,
+        call_id: None,
+        name: Some("notifications".to_string()),
+        namespace: Some("slack".to_string()),
+        output: codex_protocol::models::FunctionCallOutputPayload::from_text(
+            "new message".to_string(),
+        ),
+        internal_chat_message_metadata_passthrough: None,
+    }];
+
+    assert_eq!(
+        collect_guardian_transcript_entries(&items),
+        vec![GuardianTranscriptEntry {
+            kind: GuardianTranscriptEntryKind::Tool("tool slack.notifications result".to_string()),
+            text: "new message".to_string(),
+        }]
+    );
+
+    if let ResponseItem::FunctionCallOutput { output, .. } = &mut items[0] {
+        *output = codex_protocol::models::FunctionCallOutputPayload::from_content_items(vec![
+            FunctionCallOutputContentItem::InputImage {
+                image_url: "data:image/png;base64,image".to_string(),
+                detail: None,
+            },
+        ]);
+    }
+    assert_eq!(
+        collect_guardian_transcript_entries(&items),
+        vec![GuardianTranscriptEntry {
+            kind: GuardianTranscriptEntryKind::Tool("tool slack.notifications result".to_string()),
+            text: "[non-text output]".to_string(),
+        }]
+    );
+}
+
 #[test]
 fn guardian_truncate_text_keeps_prefix_suffix_and_xml_marker() {
     let content = "prefix ".repeat(200) + &" suffix".repeat(200);

codex-rs/core/src/session/mod.rs

@@ -42,6 +42,7 @@ use crate::session::step_context::StepContext;
 use crate::session::turn_context::TurnEnvironment;
 use crate::session_prefix::format_inter_agent_completion_message;
 use crate::skills_load_input_from_config;
+use crate::stream_events_utils::mark_thread_memory_mode_polluted_if_external_context;
 use crate::turn_metadata::TurnMetadataState;
 use crate::turn_timing::now_unix_timestamp_ms;
 use async_channel::Receiver;
@@ -1346,12 +1347,13 @@ impl Session {
             let mut state = self.state.lock().await;
             state.set_next_turn_is_first(!has_prior_user_turns);
         }
-        match conversation_history {
+        let turn_context = match conversation_history {
             InitialHistory::New | InitialHistory::Cleared => {
                 // Defer initial context insertion until the first real turn starts so
                 // turn/start overrides can be merged before we write model-visible context.
                 self.set_previous_turn_settings(/*previous_turn_settings*/ None)
                     .await;
+                None
             }
             InitialHistory::Resumed(resumed_history) => {
                 let turn_context = self.new_default_turn().await;
@@ -1401,6 +1403,7 @@ impl Session {
                 if !is_subagent {
                     let _ = self.flush_rollout().await;
                 }
+                None
             }
             InitialHistory::Forked(mut rollout_items) => {
                 let turn_context = self.new_default_turn().await;
@@ -1449,6 +1452,19 @@ impl Session {
                 if !is_subagent {
                     let _ = self.flush_rollout().await;
                 }
+                Some(turn_context)
+            }
+        };
+        if let Some(turn_context) = turn_context
+            && turn_context.config.memories.disable_on_external_context
+        {
+            let history = self.clone_history().await;
+            if let Some(item) = history
+                .raw_items()
+                .find(|item| matches!(item, ResponseItem::FunctionCallOutput { call_id: None, .. }))
+            {
+                mark_thread_memory_mode_polluted_if_external_context(self, &turn_context, item)
+                    .await;
             }
         }
     }
@@ -3087,6 +3103,13 @@ impl Session {
         let rollout_items: Vec<RolloutItem> =
             items.into_iter().map(RolloutItem::ResponseItem).collect();
         self.persist_rollout_items(&rollout_items).await;
+        if turn_context.config.memories.disable_on_external_context
+            && let Some(item) = response_items
+                .iter()
+                .find(|item| matches!(item, ResponseItem::FunctionCallOutput { call_id: None, .. }))
+        {
+            mark_thread_memory_mode_polluted_if_external_context(self, turn_context, item).await;
+        }
         self.send_raw_response_items(turn_context, &response_items)
             .await;
     }

codex-rs/core/src/stream_events_utils.rs

@@ -135,6 +135,7 @@ fn response_item_may_include_external_context(item: &ResponseItem) -> bool {
         ResponseItem::ToolSearchCall { .. }
             | ResponseItem::ToolSearchOutput { .. }
             | ResponseItem::WebSearchCall { .. }
+            | ResponseItem::FunctionCallOutput { call_id: None, .. }
     )
 }
 

codex-rs/core/src/stream_events_utils_tests.rs

@@ -70,6 +70,14 @@ fn external_context_pollution_items_include_web_search_and_tool_search() {
             tools: Vec::new(),
             internal_chat_message_metadata_passthrough: None,
         },
+        ResponseItem::FunctionCallOutput {
+            id: None,
+            call_id: None,
+            name: Some("notifications".to_string()),
+            namespace: Some("slack".to_string()),
+            output: FunctionCallOutputPayload::from_text("new message".to_string()),
+            internal_chat_message_metadata_passthrough: None,
+        },
     ];
 
     assert!(

codex-rs/ext/guardian-v2/src/async_scorer/transcript.rs

@@ -247,6 +247,29 @@ impl TranscriptConfig {
                     );
                     (role, output)
                 }
+                ResponseItem::FunctionCallOutput {
+                    call_id: None,
+                    name,
+                    namespace,
+                    output,
+                    ..
+                } => {
+                    if !self.sources.contains(&TranscriptSource::ToolOutputs) {
+                        continue;
+                    }
+                    let output = output
+                        .body
+                        .to_text()
+                        .unwrap_or_else(|| "[non-text output]".into());
+                    let role = match (name.as_deref(), namespace.as_deref()) {
+                        (Some(name), Some(namespace)) => {
+                            format!("tool {namespace}.{name} result")
+                        }
+                        (Some(name), None) => format!("tool {name} result"),
+                        (None, _) => "tool result".to_owned(),
+                    };
+                    (role, output)
+                }
                 ResponseItem::Reasoning {
                     summary, content, ..
                 } => {
@@ -289,7 +312,6 @@ impl TranscriptConfig {
                     ("tool web_search call".to_owned(), text)
                 }
                 ResponseItem::AdditionalTools { .. }
-                | ResponseItem::FunctionCallOutput { call_id: None, .. }
                 | ResponseItem::ImageGenerationCall { .. }
                 | ResponseItem::ToolSearchCall { .. }
                 | ResponseItem::ToolSearchOutput { .. }

codex-rs/ext/guardian-v2/src/async_scorer/transcript_tests.rs

@@ -485,6 +485,36 @@ fn transcript_truncates_tool_results_using_standard_budget() {
     );
 }
 
+#[test]
+fn transcript_preserves_named_unpaired_tool_source() {
+    let mut items = vec![ResponseItem::FunctionCallOutput {
+        id: None,
+        call_id: None,
+        name: Some("notifications".to_owned()),
+        namespace: Some("slack".to_owned()),
+        output: FunctionCallOutputPayload::from_text("new message".to_owned()),
+        internal_chat_message_metadata_passthrough: None,
+    }];
+
+    assert_eq!(
+        TranscriptConfig::default().build(&items),
+        vec!["[1] tool slack.notifications result: new message\n"]
+    );
+
+    if let ResponseItem::FunctionCallOutput { output, .. } = &mut items[0] {
+        *output = FunctionCallOutputPayload::from_content_items(vec![
+            FunctionCallOutputContentItem::InputImage {
+                image_url: "data:image/png;base64,image".to_owned(),
+                detail: None,
+            },
+        ]);
+    }
+    assert_eq!(
+        TranscriptConfig::default().build(&items),
+        vec!["[1] tool slack.notifications result: [non-text output]\n"]
+    );
+}
+
 #[test]
 fn configured_reasoning_counts_against_message_budget() {
     let mut items = (0..8)

codex-rs/ext/image-generation/src/tests.rs

@@ -138,10 +138,10 @@ async fn recent_image_fallback_selects_newest_images_in_chronological_order() {
         },
         ResponseItem::FunctionCallOutput {
             id: None,
-            call_id: Some("orphan-call".to_string()),
+            call_id: None,
-            name: None,
+            name: Some("notifications".to_string()),
-            namespace: None,
+            namespace: Some("slack".to_string()),
-            output: image_output("orphan"),
+            output: image_output("standalone"),
             internal_chat_message_metadata_passthrough: None,
         },
     ];
@@ -151,7 +151,7 @@ async fn recent_image_fallback_selects_newest_images_in_chronological_order() {
             &ImagegenArgs {
                 prompt: "change the lighting".to_string(),
                 referenced_image_paths: None,
-                num_last_images_to_include: Some(4),
+                num_last_images_to_include: Some(5),
             },
             &history,
             &[],
@@ -160,7 +160,7 @@ async fn recent_image_fallback_selects_newest_images_in_chronological_order() {
         .expect("history-backed edit request should build"),
         ImageRequest::Edit(expected_edit_request(
             "change the lighting",
-            &["user-2", "mcp", "code-mode", "generated"],
+            &["user-2", "mcp", "code-mode", "generated", "standalone"],
         ))
     );
 }

codex-rs/ext/image-generation/src/tool.rs

@@ -1,4 +1,3 @@
-use std::collections::HashSet;
 use std::io;
 
 use base64::Engine;
@@ -470,34 +469,6 @@ async fn request_for_call_args(
 }
 
 fn recent_images(history: &[ResponseItem], count: usize) -> Vec<ImageUrl> {
-    let mut function_call_ids = HashSet::new();
-    let mut custom_tool_call_ids = HashSet::new();
-    for item in history {
-        match item {
-            ResponseItem::FunctionCall { call_id, .. } => {
-                function_call_ids.insert(call_id.as_str());
-            }
-            ResponseItem::CustomToolCall { call_id, .. } => {
-                custom_tool_call_ids.insert(call_id.as_str());
-            }
-            ResponseItem::AdditionalTools { .. }
-            | ResponseItem::Message { .. }
-            | ResponseItem::AgentMessage { .. }
-            | ResponseItem::Reasoning { .. }
-            | ResponseItem::LocalShellCall { .. }
-            | ResponseItem::ToolSearchCall { .. }
-            | ResponseItem::FunctionCallOutput { .. }
-            | ResponseItem::CustomToolCallOutput { .. }
-            | ResponseItem::ToolSearchOutput { .. }
-            | ResponseItem::WebSearchCall { .. }
-            | ResponseItem::ImageGenerationCall { .. }
-            | ResponseItem::Compaction { .. }
-            | ResponseItem::CompactionTrigger { .. }
-            | ResponseItem::ContextCompaction { .. }
-            | ResponseItem::Other => {}
-        }
-    }
-
     let mut images = Vec::with_capacity(count);
     'history: for item in history.iter().rev() {
         let mut image_urls = Vec::new();
@@ -510,16 +481,8 @@ fn recent_images(history: &[ResponseItem], count: usize) -> Vec<ImageUrl> {
                     | ContentItem::OutputText { .. } => None,
                 }));
             }
-            ResponseItem::FunctionCallOutput {
+            ResponseItem::FunctionCallOutput { output, .. }
-                call_id: Some(call_id),
+            | ResponseItem::CustomToolCallOutput { output, .. } => {
-                output,
-                ..
-            } if function_call_ids.contains(call_id.as_str()) => {
-                image_urls.extend(output_image_urls(output));
-            }
-            ResponseItem::CustomToolCallOutput {
-                call_id, output, ..
-            } if custom_tool_call_ids.contains(call_id.as_str()) => {
                 image_urls.extend(output_image_urls(output));
             }
             ResponseItem::ImageGenerationCall { result, .. } if !result.is_empty() => {
@@ -532,8 +495,6 @@ fn recent_images(history: &[ResponseItem], count: usize) -> Vec<ImageUrl> {
             | ResponseItem::FunctionCall { .. }
             | ResponseItem::ToolSearchCall { .. }
             | ResponseItem::CustomToolCall { .. }
-            | ResponseItem::FunctionCallOutput { .. }
-            | ResponseItem::CustomToolCallOutput { .. }
             | ResponseItem::ToolSearchOutput { .. }
             | ResponseItem::WebSearchCall { .. }
             | ResponseItem::ImageGenerationCall { .. }