feat: preserve output schema across Codex turns

README.md

@@ -99,13 +99,13 @@ turn's `exec resume` command.
   `:dangerously_bypass_approvals_and_sandbox`, `:skip_git_repo_check`,
   `:ephemeral`,
   `:config_overrides`, `:enabled_features`, `:disabled_features`,
-  `:images`
+  `:images`, `:output_schema`
 
 These settings are forwarded on fresh and resumed turns. Sandbox and
 approval policy become supported `-c` overrides on resume.
 `:working_dir` / `:cwd` remains the subprocess directory on both turns.
 Options that the resume command cannot preserve (`:cd`, `:add_dirs`,
-`:search`, `:output_schema`) fail at session startup with
+`:search`) fail at session startup with
 `{:error, {:unsupported_resume_option, option}}`.
 
 **Backend-only:**

lib/gen_agent/backends/codex.ex

@@ -2,7 +2,7 @@ defmodule GenAgent.Backends.Codex do
   @moduledoc """
   `GenAgent.Backend` implementation backed by `CodexWrapper`.
 
-  CodexWrapper 0.5.2 streams NDJSON while closing CLI stdin. This
+  CodexWrapper 0.5.3 streams NDJSON while closing CLI stdin. This
   backend forwards translated events as they arrive, so
   `handle_stream_event/2` can observe progress during a turn.
 
@@ -34,10 +34,10 @@ defmodule GenAgent.Backends.Codex do
       `:dangerously_bypass_approvals_and_sandbox`, `:skip_git_repo_check`,
       `:ephemeral`,
       `:config_overrides`, `:enabled_features`, `:disabled_features`,
-      `:images`
+      `:images`, `:output_schema`
 
   Options that cannot be preserved on `exec resume` (`:cd`,
-  `:add_dirs`, `:search`, `:output_schema`) are rejected by
+  `:add_dirs`, `:search`) are rejected by
   `start_session/1`. Use `:working_dir` / `:cwd` for a directory that
   persists across turns. Session options are translated into supported
   resume arguments; `:sandbox` and `:approval_policy` use config
@@ -71,7 +71,8 @@ defmodule GenAgent.Backends.Codex do
     :config_overrides,
     :enabled_features,
     :disabled_features,
-    :images
+    :images,
+    :output_schema
   ]
 
   defstruct [
@@ -186,6 +187,9 @@ defmodule GenAgent.Backends.Codex do
       {:images, v}, e ->
         Enum.reduce(v, e, &Exec.image(&2, &1))
 
+      {:output_schema, v}, e ->
+        Exec.output_schema(e, v)
+
       _other, e ->
         e
     end)
@@ -229,6 +233,9 @@ defmodule GenAgent.Backends.Codex do
         {:images, values}, r ->
           Enum.reduce(values, r, &ExecResume.image(&2, &1))
 
+        {:output_schema, value}, r ->
+          ExecResume.output_schema(r, value)
+
         _other, r ->
           r
       end)

mix.exs

@@ -32,7 +32,7 @@ defmodule GenAgentCodex.MixProject do
   defp deps do
     [
       {:gen_agent, "~> 0.2.0"},
-      {:codex_wrapper, "~> 0.5.2"},
+      {:codex_wrapper, "~> 0.5.3"},
       {:ex_doc, "~> 0.35", only: :dev, runtime: false},
       {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
       {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false}

mix.lock

@@ -1,6 +1,6 @@
 %{
   "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
-  "codex_wrapper": {:hex, :codex_wrapper, "0.5.2", "8c91e2972e0055cf437f3fbc9ac4842a41dd5c073a575c02c41cea570fe47a74", [:mix], [{:forcola, "~> 0.3.5", [hex: :forcola, repo: "hexpm", optional: true]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "c58693fc249decc101f71b1aee7d30d5bdb64b072729ffc7548a66f8aa7d75e6"},
+  "codex_wrapper": {:hex, :codex_wrapper, "0.5.3", "278806a6a0e4b91a6ac5398edcfc3524162f2220e2ee85917cd12bb0ecef747a", [:mix], [{:forcola, "~> 0.3.5", [hex: :forcola, repo: "hexpm", optional: true]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "a93b0a27b2520e34fc5d90d91c208509ed4081fa678c7f0af25750f90893d9a7"},
   "credo": {:hex, :credo, "1.7.19", "cc52129665fc7c15143d47838fda0f9cd6dac9ceced7bf4da6f85fcbfe64b12a", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "2d8bc95d5a7bb99dd2613621d4f08c6a3575c3fd4b62e6a2b48a100352a557b8"},
   "dialyxir": {:hex, :dialyxir, "1.4.8", "7ef671a8aff9948b091d8c30f09467fbb16e77305cda451bce48109a0f5e021c", [:mix], [{:erlex, ">= 0.2.8", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "cbd5a851571e5dfeb32aaf2e840bfa98b7864cb3071bf2ef5d95d1276b12e072"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.46", "67607a0532e810c6f630a515c548d0b24949643f168cc556303bee4cf96105c7", [:mix], [], "hexpm", "9c44636e8a1c68c62f526b2dcd85d941dbbcee7ab82cf64ba06ce28bef8e89f5"},

test/gen_agent/backends/codex_executable_conformance_test.exs

@@ -90,6 +90,7 @@ defmodule GenAgent.Backends.CodexExecutableConformanceTest do
         enabled_features: ["fixture_feature"],
         disabled_features: ["other_feature"],
         images: ["/fixture/image.png"],
+        output_schema: "/fixture/response.json",
         env: [{"GEN_AGENT_FIXTURE", "configured"}]
       )
 
@@ -120,6 +121,10 @@ defmodule GenAgent.Backends.CodexExecutableConformanceTest do
     assert "fixture-model" in fresh_args
     assert "read-only" in fresh_args
     assert "first prompt" == List.last(fresh_args)
+
+    assert Enum.chunk_every(fresh_args, 2, 1, :discard)
+           |> Enum.member?(["--output-schema", "/fixture/response.json"])
+
     assert File.read!(Path.join(context.directory, "fresh.env")) == "configured\n"
 
     assert {:ok, second} = GenAgent.ask(name, "follow-up prompt")
@@ -133,6 +138,10 @@ defmodule GenAgent.Backends.CodexExecutableConformanceTest do
     assert "fixture_feature" in resume_args
     assert "other_feature" in resume_args
     assert "/fixture/image.png" in resume_args
+
+    assert Enum.chunk_every(resume_args, 2, 1, :discard)
+           |> Enum.member?(["--output-schema", "/fixture/response.json"])
+
     assert "follow-up prompt" == List.last(resume_args)
     assert Enum.any?(resume_args, &String.contains?(&1, "approval_policy"))
     assert Enum.any?(resume_args, &String.contains?(&1, "mcp_servers.fixture.enabled=false"))

test/gen_agent/backends/codex_streaming_test.exs

@@ -79,7 +79,7 @@ defmodule GenAgent.Backends.CodexStreamingTest do
   end
 
   test "options that cannot be preserved on resume fail at startup" do
-    for option <- [:cd, :add_dirs, :search, :output_schema] do
+    for option <- [:cd, :add_dirs, :search] do
       assert {:error, {:unsupported_resume_option, ^option}} =
                Codex.start_session([{option, "fixture"}])
     end