Expose session id to exec environments

codex-rs/core/src/codex.rs

@@ -602,6 +602,10 @@ impl Session {
         self.tx_event.clone()
     }
 
+    pub(crate) fn conversation_id(&self) -> ConversationId {
+        self.conversation_id
+    }
+
     fn next_internal_sub_id(&self) -> String {
         let id = self
             .next_internal_sub_id

codex-rs/core/src/exec_env.rs

@@ -4,6 +4,8 @@ use crate::config_types::ShellEnvironmentPolicyInherit;
 use std::collections::HashMap;
 use std::collections::HashSet;
 
+pub const CODEX_SESSION_ID_ENV_VAR: &str = "CODEX_SESSION_ID";
+
 /// Construct an environment map based on the rules in the specified policy. The
 /// resulting map can be passed directly to `Command::envs()` after calling
 /// `env_clear()` to ensure no unintended variables are leaked to the spawned

codex-rs/core/src/tools/handlers/shell.rs

@@ -2,8 +2,10 @@ use async_trait::async_trait;
 use codex_protocol::models::ShellToolCallParams;
 use std::sync::Arc;
 
+use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::exec::ExecParams;
+use crate::exec_env::CODEX_SESSION_ID_ENV_VAR;
 use crate::exec_env::create_env;
 use crate::function_tool::FunctionCallError;
 use crate::tools::context::ToolInvocation;
@@ -16,12 +18,22 @@ use crate::tools::registry::ToolKind;
 pub struct ShellHandler;
 
 impl ShellHandler {
-    fn to_exec_params(params: ShellToolCallParams, turn_context: &TurnContext) -> ExecParams {
+    fn to_exec_params(
+        params: ShellToolCallParams,
+        session: &Session,
+        turn_context: &TurnContext,
+    ) -> ExecParams {
+        let mut env = create_env(&turn_context.shell_environment_policy);
+        env.insert(
+            CODEX_SESSION_ID_ENV_VAR.to_string(),
+            session.conversation_id().to_string(),
+        );
+
         ExecParams {
             command: params.command,
             cwd: turn_context.resolve_path(params.workdir.clone()),
             timeout_ms: params.timeout_ms,
-            env: create_env(&turn_context.shell_environment_policy),
+            env,
             with_escalated_permissions: params.with_escalated_permissions,
             justification: params.justification,
             arg0: None,
@@ -60,7 +72,7 @@ impl ToolHandler for ShellHandler {
                             "failed to parse function arguments: {e:?}"
                         ))
                     })?;
-                let exec_params = Self::to_exec_params(params, turn.as_ref());
+                let exec_params = Self::to_exec_params(params, session.as_ref(), turn.as_ref());
                 let content = handle_container_exec_with_params(
                     tool_name.as_str(),
                     exec_params,
@@ -76,7 +88,7 @@ impl ToolHandler for ShellHandler {
                 })
             }
             ToolPayload::LocalShell { params } => {
-                let exec_params = Self::to_exec_params(params, turn.as_ref());
+                let exec_params = Self::to_exec_params(params, session.as_ref(), turn.as_ref());
                 let content = handle_container_exec_with_params(
                     tool_name.as_str(),
                     exec_params,
@@ -97,3 +109,31 @@ impl ToolHandler for ShellHandler {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::codex::make_session_and_context;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn to_exec_params_includes_session_id() {
+        let (session, turn) = make_session_and_context();
+        let expected_session_id = session.conversation_id().to_string();
+
+        let params = ShellToolCallParams {
+            command: vec!["echo".to_string()],
+            workdir: None,
+            timeout_ms: None,
+            with_escalated_permissions: None,
+            justification: None,
+        };
+
+        let exec_params = ShellHandler::to_exec_params(params, &session, &turn);
+
+        assert_eq!(
+            exec_params.env.get(CODEX_SESSION_ID_ENV_VAR),
+            Some(&expected_session_id)
+        );
+    }
+}

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

@@ -301,6 +301,33 @@ mod tests {
         Ok(())
     }
 
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn unified_exec_exposes_session_id_env_var() -> anyhow::Result<()> {
+        skip_if_sandbox!(Ok(()));
+
+        let (session, turn) = test_session_and_turn();
+        let expected_session_id = session.conversation_id().to_string();
+
+        let open_shell = exec_command(&session, &turn, "bash -i", Some(2_500)).await?;
+        let session_id = open_shell.session_id.expect("expected session id");
+
+        let env_output = write_stdin(
+            &session,
+            session_id,
+            "echo $CODEX_SESSION_ID\n",
+            Some(2_500),
+        )
+        .await?;
+
+        assert!(
+            env_output.output.contains(&expected_session_id),
+            "shell output did not include session id: {}",
+            env_output.output
+        );
+
+        Ok(())
+    }
+
     #[tokio::test]
     async fn unified_exec_timeouts() -> anyhow::Result<()> {
         skip_if_sandbox!(Ok(()));

codex-rs/core/src/unified_exec/session_manager.rs

@@ -5,6 +5,7 @@ use tokio::sync::mpsc;
 use tokio::time::Duration;
 use tokio::time::Instant;
 
+use crate::exec_env::CODEX_SESSION_ID_ENV_VAR;
 use crate::exec_env::create_env;
 use crate::sandboxing::ExecEnv;
 use crate::tools::orchestrator::ToolOrchestrator;
@@ -188,11 +189,12 @@ impl UnifiedExecSessionManager {
     ) -> Result<UnifiedExecSession, UnifiedExecError> {
         let mut orchestrator = ToolOrchestrator::new();
         let mut runtime = UnifiedExecRuntime::new(self);
-        let req = UnifiedExecToolRequest::new(
-            command,
-            context.turn.cwd.clone(),
-            create_env(&context.turn.shell_environment_policy),
+        let mut env = create_env(&context.turn.shell_environment_policy);
+        env.insert(
+            CODEX_SESSION_ID_ENV_VAR.to_string(),
+            context.session.conversation_id().to_string(),
         );
+        let req = UnifiedExecToolRequest::new(command, context.turn.cwd.clone(), env);
         let tool_ctx = ToolCtx {
             session: context.session,
             turn: context.turn,