diff --git a/lib/lib-review-loop b/lib/lib-review-loop
index 94b49e0..37400c7 100644
--- a/lib/lib-review-loop
+++ b/lib/lib-review-loop
@@ -151,17 +151,25 @@ run_claude() {
 
 # Run Codex CLI with a prompt.  Wraps the prompt with a preamble that prevents
 # conversational output, and disables MCP servers to avoid artifact creation.
+#
+# --sandbox workspace-write, not --full-auto: codex-cli dropped --full-auto from
+# the `exec` subcommand (gone as of 0.147.0), and an unknown flag is a hard
+# parse error, so the agent never starts and the loop exits with no review.
+# workspace-write is the equivalent policy -- `exec` is already non-interactive,
+# so there are no approvals to auto-accept, only the sandbox to widen far enough
+# that the reviewer can write agent-code-review.md.
 #   $1: prompt text
 run_codex() {
     local prompt="$1"
     local wrapped="Execute the following task now. Do not introduce yourself. Begin immediately.
 
 $prompt"
-    echo "$wrapped" | codex exec --full-auto --config 'mcp_servers={}' -
+    echo "$wrapped" | codex exec --sandbox workspace-write --config 'mcp_servers={}' -
 }
 
 # Run Antigravity CLI with a prompt in non-interactive headless mode.
-# Uses --dangerously-skip-permissions for auto-approval (equivalent to Codex --full-auto).
+# Uses --dangerously-skip-permissions for auto-approval (the Codex equivalent is
+# --sandbox workspace-write; see run_codex).
 # The prompt MUST be piped via stdin without -p: since agy 1.1.1, passing any
 # -p value disables stdin reading, and whitespace-only -p values are rejected
 # as an empty prompt. A piped stdin prompt alone still enters print mode.
diff --git a/test/lib-review-loop.bats b/test/lib-review-loop.bats
index 0f0987f..8c6ac94 100644
--- a/test/lib-review-loop.bats
+++ b/test/lib-review-loop.bats
@@ -558,3 +558,59 @@ make_run_dir() { # make_run_dir <root> <name> <days-old>
     run is_inside_dir "logs/a.log" "";          assert_failure
     run is_inside_dir "logs/a.log" "$root/nope"; assert_failure
 }
+
+# =========================================================================
+# Codex invocation
+#
+# The flags run_codex passes are a compatibility surface, not an internal
+# detail: codex rejects an unknown flag at parse time, so a stale one means
+# the agent never starts and the loop ends with no review written. That
+# failure looked like a codex problem rather than ours, so pin the contract.
+# =========================================================================
+
+stub_codex() { # records the argv it was invoked with, then succeeds
+    local dir="$BATS_TEST_TMPDIR/bin"
+    mkdir -p "$dir"
+    {
+        echo '#!/usr/bin/env bash'
+        echo 'cat >/dev/null'
+        printf 'printf "%%s\\n" "$@" > %q\n' "$BATS_TEST_TMPDIR/codex-argv"
+    } > "$dir/codex"
+    chmod +x "$dir/codex"
+    PATH="$dir:$PATH"
+}
+
+@test "run_codex does not pass --full-auto, which codex exec no longer accepts" {
+    source_lib
+    stub_codex
+    run run_agent codex "a prompt" "Read"
+    assert_success
+    run cat "$BATS_TEST_TMPDIR/codex-argv"
+    refute_output --partial "--full-auto"
+}
+
+@test "run_codex requests a sandbox that can write the review file" {
+    source_lib
+    stub_codex
+    run run_agent codex "a prompt" "Read"
+    assert_success
+    run cat "$BATS_TEST_TMPDIR/codex-argv"
+    # read-only would let the agent run but silently fail to write
+    # agent-code-review.md, which the loop reports as a dead codex.
+    assert_output --partial "--sandbox"
+    assert_output --partial "workspace-write"
+}
+
+@test "run_codex still runs exec non-interactively with MCP servers disabled" {
+    source_lib
+    stub_codex
+    run run_agent codex "a prompt" "Read"
+    assert_success
+    run cat "$BATS_TEST_TMPDIR/codex-argv"
+    assert_output --partial "exec"
+    assert_output --partial "mcp_servers={}"
+    # The trailing "-" is what makes codex read the prompt from stdin.
+    # assert_line matches a whole argument: --partial would also be satisfied
+    # by the hyphens in --sandbox, so it would pass with the "-" removed.
+    assert_line "-"
+}