feat: polluted memories (#13008)

Add a feature flag to disable memory creation for "polluted"

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

@@ -2505,6 +2505,7 @@ persistence = "none"
 
         let memories = r#"
 [memories]
+no_memories_if_mcp_or_web_search = true
 generate_memories = false
 use_memories = false
 max_raw_memories_for_global = 512
@@ -2519,6 +2520,7 @@ phase_2_model = "gpt-5"
             toml::from_str::<ConfigToml>(memories).expect("TOML deserialization should succeed");
         assert_eq!(
             Some(MemoriesToml {
+                no_memories_if_mcp_or_web_search: Some(true),
                 generate_memories: Some(false),
                 use_memories: Some(false),
                 max_raw_memories_for_global: Some(512),
@@ -2541,6 +2543,7 @@ phase_2_model = "gpt-5"
         assert_eq!(
             config.memories,
             MemoriesConfig {
+                no_memories_if_mcp_or_web_search: true,
                 generate_memories: false,
                 use_memories: false,
                 max_raw_memories_for_global: 512,

codex-rs/core/src/config/types.rs

@@ -371,6 +371,8 @@ pub struct FeedbackConfigToml {
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, JsonSchema)]
 #[schemars(deny_unknown_fields)]
 pub struct MemoriesToml {
+    /// When `true`, web searches and MCP tool calls mark the thread `memory_mode` as `"polluted"`.
+    pub no_memories_if_mcp_or_web_search: Option<bool>,
     /// When `false`, newly created threads are stored with `memory_mode = "disabled"` in the state DB.
     pub generate_memories: Option<bool>,
     /// When `false`, skip injecting memory usage instructions into developer prompts.
@@ -394,6 +396,7 @@ pub struct MemoriesToml {
 /// Effective memories settings after defaults are applied.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct MemoriesConfig {
+    pub no_memories_if_mcp_or_web_search: bool,
     pub generate_memories: bool,
     pub use_memories: bool,
     pub max_raw_memories_for_global: usize,
@@ -408,6 +411,7 @@ pub struct MemoriesConfig {
 impl Default for MemoriesConfig {
     fn default() -> Self {
         Self {
+            no_memories_if_mcp_or_web_search: false,
             generate_memories: true,
             use_memories: true,
             max_raw_memories_for_global: DEFAULT_MEMORIES_MAX_RAW_MEMORIES_FOR_GLOBAL,
@@ -425,6 +429,9 @@ impl From<MemoriesToml> for MemoriesConfig {
     fn from(toml: MemoriesToml) -> Self {
         let defaults = Self::default();
         Self {
+            no_memories_if_mcp_or_web_search: toml
+                .no_memories_if_mcp_or_web_search
+                .unwrap_or(defaults.no_memories_if_mcp_or_web_search),
             generate_memories: toml.generate_memories.unwrap_or(defaults.generate_memories),
             use_memories: toml.use_memories.unwrap_or(defaults.use_memories),
             max_raw_memories_for_global: toml

codex-rs/core/src/mcp_tool_call.rs

@@ -15,6 +15,7 @@ use crate::protocol::EventMsg;
 use crate::protocol::McpInvocation;
 use crate::protocol::McpToolCallBeginEvent;
 use crate::protocol::McpToolCallEndEvent;
+use crate::state_db;
 use codex_protocol::mcp::CallToolResult;
 use codex_protocol::models::FunctionCallOutputBody;
 use codex_protocol::models::FunctionCallOutputPayload;
@@ -121,6 +122,7 @@ pub(crate) async fn handle_mcp_tool_call(
                 });
                 notify_mcp_tool_call_event(sess.as_ref(), turn_context, tool_call_begin_event)
                     .await;
+                maybe_mark_thread_memory_mode_polluted(sess.as_ref(), turn_context).await;
 
                 let start = Instant::now();
                 let result = sess
@@ -189,6 +191,7 @@ pub(crate) async fn handle_mcp_tool_call(
         invocation: invocation.clone(),
     });
     notify_mcp_tool_call_event(sess.as_ref(), turn_context, tool_call_begin_event).await;
+    maybe_mark_thread_memory_mode_polluted(sess.as_ref(), turn_context).await;
 
     let start = Instant::now();
     // Perform the tool call.
@@ -224,6 +227,22 @@ pub(crate) async fn handle_mcp_tool_call(
     ResponseInputItem::McpToolCallOutput { call_id, result }
 }
 
+async fn maybe_mark_thread_memory_mode_polluted(sess: &Session, turn_context: &TurnContext) {
+    if !turn_context
+        .config
+        .memories
+        .no_memories_if_mcp_or_web_search
+    {
+        return;
+    }
+    state_db::mark_thread_memory_mode_polluted(
+        sess.services.state_db.as_deref(),
+        sess.conversation_id,
+        "mcp_tool_call",
+    )
+    .await;
+}
+
 fn sanitize_mcp_tool_result_for_model(
     supports_image_input: bool,
     result: Result<CallToolResult, String>,

codex-rs/core/src/personality_migration.rs

@@ -177,6 +177,7 @@ mod tests {
                 model_provider: None,
                 base_instructions: None,
                 dynamic_tools: None,
+                memory_mode: None,
             },
             git: None,
         };

codex-rs/core/src/rollout/metadata.rs

@@ -129,6 +129,13 @@ pub(crate) async fn extract_metadata_from_rollout(
     }
     Ok(ExtractionOutcome {
         metadata,
+        memory_mode: items.iter().rev().find_map(|item| match item {
+            RolloutItem::SessionMeta(meta_line) => meta_line.meta.memory_mode.clone(),
+            RolloutItem::ResponseItem(_)
+            | RolloutItem::Compacted(_)
+            | RolloutItem::TurnContext(_)
+            | RolloutItem::EventMsg(_) => None,
+        }),
         parse_errors,
     })
 }
@@ -272,6 +279,7 @@ pub(crate) async fn backfill_sessions(
                         );
                     }
                     let mut metadata = outcome.metadata;
+                    let memory_mode = outcome.memory_mode.unwrap_or_else(|| "enabled".to_string());
                     if rollout.archived && metadata.archived_at.is_none() {
                         let fallback_archived_at = metadata.updated_at;
                         metadata.archived_at = file_modified_time_utc(&rollout.path)
@@ -282,6 +290,17 @@ pub(crate) async fn backfill_sessions(
                         stats.failed = stats.failed.saturating_add(1);
                         warn!("failed to upsert rollout {}: {err}", rollout.path.display());
                     } else {
+                        if let Err(err) = runtime
+                            .set_thread_memory_mode(metadata.id, memory_mode.as_str())
+                            .await
+                        {
+                            stats.failed = stats.failed.saturating_add(1);
+                            warn!(
+                                "failed to restore memory mode for {}: {err}",
+                                rollout.path.display()
+                            );
+                            continue;
+                        }
                         stats.upserted = stats.upserted.saturating_add(1);
                         if let Ok(meta_line) =
                             rollout::list::read_session_meta_line(&rollout.path).await
@@ -519,6 +538,7 @@ mod tests {
             model_provider: Some("openai".to_string()),
             base_instructions: None,
             dynamic_tools: None,
+            memory_mode: None,
         };
         let session_meta_line = SessionMetaLine {
             meta: session_meta,
@@ -543,9 +563,71 @@ mod tests {
         expected.updated_at = file_modified_time_utc(&path).await.expect("mtime");
 
         assert_eq!(outcome.metadata, expected);
+        assert_eq!(outcome.memory_mode, None);
         assert_eq!(outcome.parse_errors, 0);
     }
 
+    #[tokio::test]
+    async fn extract_metadata_from_rollout_returns_latest_memory_mode() {
+        let dir = tempdir().expect("tempdir");
+        let uuid = Uuid::new_v4();
+        let id = ThreadId::from_string(&uuid.to_string()).expect("thread id");
+        let path = dir
+            .path()
+            .join(format!("rollout-2026-01-27T12-34-56-{uuid}.jsonl"));
+
+        let session_meta = SessionMeta {
+            id,
+            forked_from_id: None,
+            timestamp: "2026-01-27T12:34:56Z".to_string(),
+            cwd: dir.path().to_path_buf(),
+            originator: "cli".to_string(),
+            cli_version: "0.0.0".to_string(),
+            source: SessionSource::default(),
+            agent_nickname: None,
+            agent_role: None,
+            model_provider: Some("openai".to_string()),
+            base_instructions: None,
+            dynamic_tools: None,
+            memory_mode: None,
+        };
+        let polluted_meta = SessionMeta {
+            memory_mode: Some("polluted".to_string()),
+            ..session_meta.clone()
+        };
+        let lines = vec![
+            RolloutLine {
+                timestamp: "2026-01-27T12:34:56Z".to_string(),
+                item: RolloutItem::SessionMeta(SessionMetaLine {
+                    meta: session_meta,
+                    git: None,
+                }),
+            },
+            RolloutLine {
+                timestamp: "2026-01-27T12:35:00Z".to_string(),
+                item: RolloutItem::SessionMeta(SessionMetaLine {
+                    meta: polluted_meta,
+                    git: None,
+                }),
+            },
+        ];
+        let mut file = File::create(&path).expect("create rollout");
+        for line in lines {
+            writeln!(
+                file,
+                "{}",
+                serde_json::to_string(&line).expect("serialize rollout line")
+            )
+            .expect("write rollout line");
+        }
+
+        let outcome = extract_metadata_from_rollout(&path, "openai", None)
+            .await
+            .expect("extract");
+
+        assert_eq!(outcome.memory_mode.as_deref(), Some("polluted"));
+    }
+
     #[test]
     fn builder_from_items_falls_back_to_filename() {
         let dir = tempdir().expect("tempdir");
@@ -669,6 +751,7 @@ mod tests {
             model_provider: Some("test-provider".to_string()),
             base_instructions: None,
             dynamic_tools: None,
+            memory_mode: None,
         };
         let session_meta_line = SessionMetaLine {
             meta: session_meta,

codex-rs/core/src/rollout/recorder.rs

@@ -412,6 +412,8 @@ impl RolloutRecorder {
                         } else {
                             Some(dynamic_tools)
                         },
+                        memory_mode: (!config.memories.generate_memories)
+                            .then_some("disabled".to_string()),
                     };
 
                     (

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

@@ -1109,6 +1109,7 @@ async fn test_updated_at_uses_file_mtime() -> Result<()> {
                 model_provider: Some("test-provider".into()),
                 base_instructions: None,
                 dynamic_tools: None,
+                memory_mode: None,
             },
             git: None,
         }),

codex-rs/core/src/state_db.rs

@@ -337,6 +337,19 @@ pub async fn persist_dynamic_tools(
     }
 }
 
+pub async fn mark_thread_memory_mode_polluted(
+    context: Option<&codex_state::StateRuntime>,
+    thread_id: ThreadId,
+    stage: &str,
+) {
+    let Some(ctx) = context else {
+        return;
+    };
+    if let Err(err) = ctx.mark_thread_memory_mode_polluted(thread_id).await {
+        warn!("state db mark_thread_memory_mode_polluted failed during {stage}: {err}");
+    }
+}
+
 /// Reconcile rollout items into SQLite, falling back to scanning the rollout file.
 pub async fn reconcile_rollout(
     context: Option<&codex_state::StateRuntime>,
@@ -375,6 +388,7 @@ pub async fn reconcile_rollout(
             }
         };
     let mut metadata = outcome.metadata;
+    let memory_mode = outcome.memory_mode.unwrap_or_else(|| "enabled".to_string());
     metadata.cwd = normalize_cwd_for_state_db(&metadata.cwd);
     match archived_only {
         Some(true) if metadata.archived_at.is_none() => {
@@ -392,6 +406,16 @@ pub async fn reconcile_rollout(
         );
         return;
     }
+    if let Err(err) = ctx
+        .set_thread_memory_mode(metadata.id, memory_mode.as_str())
+        .await
+    {
+        warn!(
+            "state db reconcile_rollout memory_mode update failed {}: {err}",
+            rollout_path.display()
+        );
+        return;
+    }
     if let Ok(meta_line) = crate::rollout::list::read_session_meta_line(rollout_path).await {
         persist_dynamic_tools(
             Some(ctx),

codex-rs/core/src/stream_events_utils.rs

@@ -58,9 +58,31 @@ pub(crate) async fn record_completed_response_item(
 ) {
     sess.record_conversation_items(turn_context, std::slice::from_ref(item))
         .await;
+    maybe_mark_thread_memory_mode_polluted_from_web_search(sess, turn_context, item).await;
     record_stage1_output_usage_for_completed_item(turn_context, item).await;
 }
 
+async fn maybe_mark_thread_memory_mode_polluted_from_web_search(
+    sess: &Session,
+    turn_context: &TurnContext,
+    item: &ResponseItem,
+) {
+    if !turn_context
+        .config
+        .memories
+        .no_memories_if_mcp_or_web_search
+        || !matches!(item, ResponseItem::WebSearchCall { .. })
+    {
+        return;
+    }
+    state_db::mark_thread_memory_mode_polluted(
+        sess.services.state_db.as_deref(),
+        sess.conversation_id,
+        "record_completed_response_item",
+    )
+    .await;
+}
+
 async fn record_stage1_output_usage_for_completed_item(
     turn_context: &TurnContext,
     item: &ResponseItem,