[codex] Add unsandboxed process exec API (#19040)

## Why

App-server clients sometimes need argv-based local process execution
while sandbox policy is controlled outside Codex. Those environments can
reject sandbox-disabling paths before a command ever starts, even when
the caller intentionally wants unsandboxed execution.

This PR adds a distinct `process/*` API for that use case instead of
extending `command/exec` with another sandbox-disabling shape. Keeping
the new surface separate also makes the future removal of `command/exec`
simpler: clients that need explicit process lifecycle control can move
to the newer handle-based API without depending on `command/exec`
business logic.

## What changed

- Added v2 process lifecycle methods: `process/spawn`,
`process/writeStdin`, `process/resizePty`, and `process/kill`.
- Added process notifications: `process/outputDelta` for streamed
stdout/stderr chunks and `process/exited` for final exit status and
buffered output.
- Made `process/spawn` intentionally unsandboxed and omitted
sandbox-selection fields such as `sandboxPolicy` and
`permissionProfile`.
- Added client-supplied, connection-scoped `processHandle` values for
follow-up control requests and notification routing.
- Supported cwd, environment overrides, PTY mode and size, stdin
streaming, stdout/stderr streaming, per-stream output caps, and timeout
controls.
- Killed active process sessions when the originating app-server
connection closes.
- Wired the implementation through the modular `request_processors/`
app-server layout, with process-handle request serialization for
follow-up control calls.
- Updated generated JSON/TypeScript schema fixtures and documented the
new API in `codex-rs/app-server/README.md`.
- Added v2 app-server integration coverage in
`codex-rs/app-server/tests/suite/v2/process_exec.rs` for spawn
acknowledgement before exit, buffered output caps, and process
termination.

## Verification

- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-app-server`

---------

Co-authored-by: Owen Lin <owen@openai.com>

codex-rs/app-server-protocol/schema/json/ClientRequest.json

@@ -2265,6 +2265,28 @@
       ],
       "type": "object"
     },
+    "ProcessTerminalSize": {
+      "description": "PTY size in character cells for `process/spawn` PTY sessions.",
+      "properties": {
+        "cols": {
+          "description": "Terminal width in character cells.",
+          "format": "uint16",
+          "minimum": 0.0,
+          "type": "integer"
+        },
+        "rows": {
+          "description": "Terminal height in character cells.",
+          "format": "uint16",
+          "minimum": 0.0,
+          "type": "integer"
+        }
+      },
+      "required": [
+        "cols",
+        "rows"
+      ],
+      "type": "object"
+    },
     "RealtimeOutputModality": {
       "enum": [
         "text",

codex-rs/app-server-protocol/schema/json/ServerNotification.json

@@ -2415,6 +2415,96 @@
       ],
       "type": "string"
     },
+    "ProcessExitedNotification": {
+      "description": "Final process exit notification for `process/spawn`.",
+      "properties": {
+        "exitCode": {
+          "description": "Process exit code.",
+          "format": "int32",
+          "type": "integer"
+        },
+        "processHandle": {
+          "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+          "type": "string"
+        },
+        "stderr": {
+          "description": "Buffered stderr capture.\n\nEmpty when stderr was streamed via `process/outputDelta`.",
+          "type": "string"
+        },
+        "stderrCapReached": {
+          "description": "Whether stderr reached `outputBytesCap`.\n\nIn streaming mode, stderr is empty and cap state is also reported on the final stderr `process/outputDelta` notification.",
+          "type": "boolean"
+        },
+        "stdout": {
+          "description": "Buffered stdout capture.\n\nEmpty when stdout was streamed via `process/outputDelta`.",
+          "type": "string"
+        },
+        "stdoutCapReached": {
+          "description": "Whether stdout reached `outputBytesCap`.\n\nIn streaming mode, stdout is empty and cap state is also reported on the final stdout `process/outputDelta` notification.",
+          "type": "boolean"
+        }
+      },
+      "required": [
+        "exitCode",
+        "processHandle",
+        "stderr",
+        "stderrCapReached",
+        "stdout",
+        "stdoutCapReached"
+      ],
+      "type": "object"
+    },
+    "ProcessOutputDeltaNotification": {
+      "description": "Base64-encoded output chunk emitted for a streaming `process/spawn` request.",
+      "properties": {
+        "capReached": {
+          "description": "True on the final streamed chunk for this stream when output was truncated by `outputBytesCap`.",
+          "type": "boolean"
+        },
+        "deltaBase64": {
+          "description": "Base64-encoded output bytes.",
+          "type": "string"
+        },
+        "processHandle": {
+          "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+          "type": "string"
+        },
+        "stream": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/ProcessOutputStream"
+            }
+          ],
+          "description": "Output stream this chunk belongs to."
+        }
+      },
+      "required": [
+        "capReached",
+        "deltaBase64",
+        "processHandle",
+        "stream"
+      ],
+      "type": "object"
+    },
+    "ProcessOutputStream": {
+      "description": "Stream label for `process/outputDelta` notifications.",
+      "oneOf": [
+        {
+          "description": "stdout stream. PTY mode multiplexes terminal output here.",
+          "enum": [
+            "stdout"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "stderr stream.",
+          "enum": [
+            "stderr"
+          ],
+          "type": "string"
+        }
+      ]
+    },
     "RateLimitReachedType": {
       "enum": [
         "rate_limit_reached",
@@ -5163,6 +5253,48 @@
       "title": "Command/exec/outputDeltaNotification",
       "type": "object"
     },
+    {
+      "description": "Stream base64-encoded stdout/stderr chunks for a running `process/spawn` session.",
+      "properties": {
+        "method": {
+          "enum": [
+            "process/outputDelta"
+          ],
+          "title": "Process/outputDeltaNotificationMethod",
+          "type": "string"
+        },
+        "params": {
+          "$ref": "#/definitions/ProcessOutputDeltaNotification"
+        }
+      },
+      "required": [
+        "method",
+        "params"
+      ],
+      "title": "Process/outputDeltaNotification",
+      "type": "object"
+    },
+    {
+      "description": "Final exit notification for a `process/spawn` session.",
+      "properties": {
+        "method": {
+          "enum": [
+            "process/exited"
+          ],
+          "title": "Process/exitedNotificationMethod",
+          "type": "string"
+        },
+        "params": {
+          "$ref": "#/definitions/ProcessExitedNotification"
+        }
+      },
+      "required": [
+        "method",
+        "params"
+      ],
+      "title": "Process/exitedNotification",
+      "type": "object"
+    },
     {
       "properties": {
         "method": {

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json

@@ -4248,6 +4248,48 @@
           "title": "Command/exec/outputDeltaNotification",
           "type": "object"
         },
+        {
+          "description": "Stream base64-encoded stdout/stderr chunks for a running `process/spawn` session.",
+          "properties": {
+            "method": {
+              "enum": [
+                "process/outputDelta"
+              ],
+              "title": "Process/outputDeltaNotificationMethod",
+              "type": "string"
+            },
+            "params": {
+              "$ref": "#/definitions/v2/ProcessOutputDeltaNotification"
+            }
+          },
+          "required": [
+            "method",
+            "params"
+          ],
+          "title": "Process/outputDeltaNotification",
+          "type": "object"
+        },
+        {
+          "description": "Final exit notification for a `process/spawn` session.",
+          "properties": {
+            "method": {
+              "enum": [
+                "process/exited"
+              ],
+              "title": "Process/exitedNotificationMethod",
+              "type": "string"
+            },
+            "params": {
+              "$ref": "#/definitions/v2/ProcessExitedNotification"
+            }
+          },
+          "required": [
+            "method",
+            "params"
+          ],
+          "title": "Process/exitedNotification",
+          "type": "object"
+        },
         {
           "properties": {
             "method": {
@@ -12655,6 +12697,122 @@
         ],
         "type": "object"
       },
+      "ProcessExitedNotification": {
+        "$schema": "http://json-schema.org/draft-07/schema#",
+        "description": "Final process exit notification for `process/spawn`.",
+        "properties": {
+          "exitCode": {
+            "description": "Process exit code.",
+            "format": "int32",
+            "type": "integer"
+          },
+          "processHandle": {
+            "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+            "type": "string"
+          },
+          "stderr": {
+            "description": "Buffered stderr capture.\n\nEmpty when stderr was streamed via `process/outputDelta`.",
+            "type": "string"
+          },
+          "stderrCapReached": {
+            "description": "Whether stderr reached `outputBytesCap`.\n\nIn streaming mode, stderr is empty and cap state is also reported on the final stderr `process/outputDelta` notification.",
+            "type": "boolean"
+          },
+          "stdout": {
+            "description": "Buffered stdout capture.\n\nEmpty when stdout was streamed via `process/outputDelta`.",
+            "type": "string"
+          },
+          "stdoutCapReached": {
+            "description": "Whether stdout reached `outputBytesCap`.\n\nIn streaming mode, stdout is empty and cap state is also reported on the final stdout `process/outputDelta` notification.",
+            "type": "boolean"
+          }
+        },
+        "required": [
+          "exitCode",
+          "processHandle",
+          "stderr",
+          "stderrCapReached",
+          "stdout",
+          "stdoutCapReached"
+        ],
+        "title": "ProcessExitedNotification",
+        "type": "object"
+      },
+      "ProcessOutputDeltaNotification": {
+        "$schema": "http://json-schema.org/draft-07/schema#",
+        "description": "Base64-encoded output chunk emitted for a streaming `process/spawn` request.",
+        "properties": {
+          "capReached": {
+            "description": "True on the final streamed chunk for this stream when output was truncated by `outputBytesCap`.",
+            "type": "boolean"
+          },
+          "deltaBase64": {
+            "description": "Base64-encoded output bytes.",
+            "type": "string"
+          },
+          "processHandle": {
+            "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+            "type": "string"
+          },
+          "stream": {
+            "allOf": [
+              {
+                "$ref": "#/definitions/v2/ProcessOutputStream"
+              }
+            ],
+            "description": "Output stream this chunk belongs to."
+          }
+        },
+        "required": [
+          "capReached",
+          "deltaBase64",
+          "processHandle",
+          "stream"
+        ],
+        "title": "ProcessOutputDeltaNotification",
+        "type": "object"
+      },
+      "ProcessOutputStream": {
+        "description": "Stream label for `process/outputDelta` notifications.",
+        "oneOf": [
+          {
+            "description": "stdout stream. PTY mode multiplexes terminal output here.",
+            "enum": [
+              "stdout"
+            ],
+            "type": "string"
+          },
+          {
+            "description": "stderr stream.",
+            "enum": [
+              "stderr"
+            ],
+            "type": "string"
+          }
+        ]
+      },
+      "ProcessTerminalSize": {
+        "description": "PTY size in character cells for `process/spawn` PTY sessions.",
+        "properties": {
+          "cols": {
+            "description": "Terminal width in character cells.",
+            "format": "uint16",
+            "minimum": 0.0,
+            "type": "integer"
+          },
+          "rows": {
+            "description": "Terminal height in character cells.",
+            "format": "uint16",
+            "minimum": 0.0,
+            "type": "integer"
+          }
+        },
+        "required": [
+          "cols",
+          "rows"
+        ],
+        "type": "object"
+      },
       "ProfileV2": {
         "additionalProperties": true,
         "properties": {

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json

@@ -9308,6 +9308,122 @@
       ],
       "type": "object"
     },
+    "ProcessExitedNotification": {
+      "$schema": "http://json-schema.org/draft-07/schema#",
+      "description": "Final process exit notification for `process/spawn`.",
+      "properties": {
+        "exitCode": {
+          "description": "Process exit code.",
+          "format": "int32",
+          "type": "integer"
+        },
+        "processHandle": {
+          "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+          "type": "string"
+        },
+        "stderr": {
+          "description": "Buffered stderr capture.\n\nEmpty when stderr was streamed via `process/outputDelta`.",
+          "type": "string"
+        },
+        "stderrCapReached": {
+          "description": "Whether stderr reached `outputBytesCap`.\n\nIn streaming mode, stderr is empty and cap state is also reported on the final stderr `process/outputDelta` notification.",
+          "type": "boolean"
+        },
+        "stdout": {
+          "description": "Buffered stdout capture.\n\nEmpty when stdout was streamed via `process/outputDelta`.",
+          "type": "string"
+        },
+        "stdoutCapReached": {
+          "description": "Whether stdout reached `outputBytesCap`.\n\nIn streaming mode, stdout is empty and cap state is also reported on the final stdout `process/outputDelta` notification.",
+          "type": "boolean"
+        }
+      },
+      "required": [
+        "exitCode",
+        "processHandle",
+        "stderr",
+        "stderrCapReached",
+        "stdout",
+        "stdoutCapReached"
+      ],
+      "title": "ProcessExitedNotification",
+      "type": "object"
+    },
+    "ProcessOutputDeltaNotification": {
+      "$schema": "http://json-schema.org/draft-07/schema#",
+      "description": "Base64-encoded output chunk emitted for a streaming `process/spawn` request.",
+      "properties": {
+        "capReached": {
+          "description": "True on the final streamed chunk for this stream when output was truncated by `outputBytesCap`.",
+          "type": "boolean"
+        },
+        "deltaBase64": {
+          "description": "Base64-encoded output bytes.",
+          "type": "string"
+        },
+        "processHandle": {
+          "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+          "type": "string"
+        },
+        "stream": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/ProcessOutputStream"
+            }
+          ],
+          "description": "Output stream this chunk belongs to."
+        }
+      },
+      "required": [
+        "capReached",
+        "deltaBase64",
+        "processHandle",
+        "stream"
+      ],
+      "title": "ProcessOutputDeltaNotification",
+      "type": "object"
+    },
+    "ProcessOutputStream": {
+      "description": "Stream label for `process/outputDelta` notifications.",
+      "oneOf": [
+        {
+          "description": "stdout stream. PTY mode multiplexes terminal output here.",
+          "enum": [
+            "stdout"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "stderr stream.",
+          "enum": [
+            "stderr"
+          ],
+          "type": "string"
+        }
+      ]
+    },
+    "ProcessTerminalSize": {
+      "description": "PTY size in character cells for `process/spawn` PTY sessions.",
+      "properties": {
+        "cols": {
+          "description": "Terminal width in character cells.",
+          "format": "uint16",
+          "minimum": 0.0,
+          "type": "integer"
+        },
+        "rows": {
+          "description": "Terminal height in character cells.",
+          "format": "uint16",
+          "minimum": 0.0,
+          "type": "integer"
+        }
+      },
+      "required": [
+        "cols",
+        "rows"
+      ],
+      "type": "object"
+    },
     "ProfileV2": {
       "additionalProperties": true,
       "properties": {
@@ -11386,6 +11502,48 @@
           "title": "Command/exec/outputDeltaNotification",
           "type": "object"
         },
+        {
+          "description": "Stream base64-encoded stdout/stderr chunks for a running `process/spawn` session.",
+          "properties": {
+            "method": {
+              "enum": [
+                "process/outputDelta"
+              ],
+              "title": "Process/outputDeltaNotificationMethod",
+              "type": "string"
+            },
+            "params": {
+              "$ref": "#/definitions/ProcessOutputDeltaNotification"
+            }
+          },
+          "required": [
+            "method",
+            "params"
+          ],
+          "title": "Process/outputDeltaNotification",
+          "type": "object"
+        },
+        {
+          "description": "Final exit notification for a `process/spawn` session.",
+          "properties": {
+            "method": {
+              "enum": [
+                "process/exited"
+              ],
+              "title": "Process/exitedNotificationMethod",
+              "type": "string"
+            },
+            "params": {
+              "$ref": "#/definitions/ProcessExitedNotification"
+            }
+          },
+          "required": [
+            "method",
+            "params"
+          ],
+          "title": "Process/exitedNotification",
+          "type": "object"
+        },
         {
           "properties": {
             "method": {

codex-rs/app-server-protocol/schema/json/v2/ProcessExitedNotification.json

@@ -0,0 +1,41 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "description": "Final process exit notification for `process/spawn`.",
+  "properties": {
+    "exitCode": {
+      "description": "Process exit code.",
+      "format": "int32",
+      "type": "integer"
+    },
+    "processHandle": {
+      "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+      "type": "string"
+    },
+    "stderr": {
+      "description": "Buffered stderr capture.\n\nEmpty when stderr was streamed via `process/outputDelta`.",
+      "type": "string"
+    },
+    "stderrCapReached": {
+      "description": "Whether stderr reached `outputBytesCap`.\n\nIn streaming mode, stderr is empty and cap state is also reported on the final stderr `process/outputDelta` notification.",
+      "type": "boolean"
+    },
+    "stdout": {
+      "description": "Buffered stdout capture.\n\nEmpty when stdout was streamed via `process/outputDelta`.",
+      "type": "string"
+    },
+    "stdoutCapReached": {
+      "description": "Whether stdout reached `outputBytesCap`.\n\nIn streaming mode, stdout is empty and cap state is also reported on the final stdout `process/outputDelta` notification.",
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "exitCode",
+    "processHandle",
+    "stderr",
+    "stderrCapReached",
+    "stdout",
+    "stdoutCapReached"
+  ],
+  "title": "ProcessExitedNotification",
+  "type": "object"
+}

codex-rs/app-server-protocol/schema/json/v2/ProcessOutputDeltaNotification.json

@@ -0,0 +1,55 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "ProcessOutputStream": {
+      "description": "Stream label for `process/outputDelta` notifications.",
+      "oneOf": [
+        {
+          "description": "stdout stream. PTY mode multiplexes terminal output here.",
+          "enum": [
+            "stdout"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "stderr stream.",
+          "enum": [
+            "stderr"
+          ],
+          "type": "string"
+        }
+      ]
+    }
+  },
+  "description": "Base64-encoded output chunk emitted for a streaming `process/spawn` request.",
+  "properties": {
+    "capReached": {
+      "description": "True on the final streamed chunk for this stream when output was truncated by `outputBytesCap`.",
+      "type": "boolean"
+    },
+    "deltaBase64": {
+      "description": "Base64-encoded output bytes.",
+      "type": "string"
+    },
+    "processHandle": {
+      "description": "Client-supplied, connection-scoped `processHandle` from `process/spawn`.",
+      "type": "string"
+    },
+    "stream": {
+      "allOf": [
+        {
+          "$ref": "#/definitions/ProcessOutputStream"
+        }
+      ],
+      "description": "Output stream this chunk belongs to."
+    }
+  },
+  "required": [
+    "capReached",
+    "deltaBase64",
+    "processHandle",
+    "stream"
+  ],
+  "title": "ProcessOutputDeltaNotification",
+  "type": "object"
+}

codex-rs/app-server-protocol/schema/typescript/v2/ProcessExitedNotification.ts

@@ -0,0 +1,42 @@
+// GENERATED CODE! DO NOT MODIFY BY HAND!
+
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+/**
+ * Final process exit notification for `process/spawn`.
+ */
+export type ProcessExitedNotification = {
+/**
+ * Client-supplied, connection-scoped `processHandle` from `process/spawn`.
+ */
+processHandle: string,
+/**
+ * Process exit code.
+ */
+exitCode: number,
+/**
+ * Buffered stdout capture.
+ *
+ * Empty when stdout was streamed via `process/outputDelta`.
+ */
+stdout: string,
+/**
+ * Whether stdout reached `outputBytesCap`.
+ *
+ * In streaming mode, stdout is empty and cap state is also reported on the
+ * final stdout `process/outputDelta` notification.
+ */
+stdoutCapReached: boolean,
+/**
+ * Buffered stderr capture.
+ *
+ * Empty when stderr was streamed via `process/outputDelta`.
+ */
+stderr: string,
+/**
+ * Whether stderr reached `outputBytesCap`.
+ *
+ * In streaming mode, stderr is empty and cap state is also reported on the
+ * final stderr `process/outputDelta` notification.
+ */
+stderrCapReached: boolean, };

codex-rs/app-server-protocol/schema/typescript/v2/ProcessOutputDeltaNotification.ts

@@ -0,0 +1,26 @@
+// GENERATED CODE! DO NOT MODIFY BY HAND!
+
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ProcessOutputStream } from "./ProcessOutputStream";
+
+/**
+ * Base64-encoded output chunk emitted for a streaming `process/spawn` request.
+ */
+export type ProcessOutputDeltaNotification = {
+/**
+ * Client-supplied, connection-scoped `processHandle` from `process/spawn`.
+ */
+processHandle: string,
+/**
+ * Output stream this chunk belongs to.
+ */
+stream: ProcessOutputStream,
+/**
+ * Base64-encoded output bytes.
+ */
+deltaBase64: string,
+/**
+ * True on the final streamed chunk for this stream when output was
+ * truncated by `outputBytesCap`.
+ */
+capReached: boolean, };

codex-rs/app-server-protocol/schema/typescript/v2/ProcessOutputStream.ts

@@ -0,0 +1,8 @@
+// GENERATED CODE! DO NOT MODIFY BY HAND!
+
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+/**
+ * Stream label for `process/outputDelta` notifications.
+ */
+export type ProcessOutputStream = "stdout" | "stderr";

codex-rs/app-server-protocol/schema/typescript/v2/ProcessTerminalSize.ts

@@ -0,0 +1,16 @@
+// GENERATED CODE! DO NOT MODIFY BY HAND!
+
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+/**
+ * PTY size in character cells for `process/spawn` PTY sessions.
+ */
+export type ProcessTerminalSize = {
+/**
+ * Terminal height in character cells.
+ */
+rows: number,
+/**
+ * Terminal width in character cells.
+ */
+cols: number, };

codex-rs/app-server-protocol/schema/typescript/v2/index.ts

@@ -295,6 +295,10 @@ export type { PluginSummary } from "./PluginSummary";
 export type { PluginUninstallParams } from "./PluginUninstallParams";
 export type { PluginUninstallResponse } from "./PluginUninstallResponse";
 export type { PluginsMigration } from "./PluginsMigration";
+export type { ProcessExitedNotification } from "./ProcessExitedNotification";
+export type { ProcessOutputDeltaNotification } from "./ProcessOutputDeltaNotification";
+export type { ProcessOutputStream } from "./ProcessOutputStream";
+export type { ProcessTerminalSize } from "./ProcessTerminalSize";
 export type { ProfileV2 } from "./ProfileV2";
 export type { RateLimitReachedType } from "./RateLimitReachedType";
 export type { RateLimitSnapshot } from "./RateLimitSnapshot";