diff --git a/codex-rs/Cargo.lock b/codex-rs/Cargo.lock
index cec9d56862e..95a6e3ad259 100644
--- a/codex-rs/Cargo.lock
+++ b/codex-rs/Cargo.lock
@@ -4803,7 +4803,6 @@ dependencies = [
 name = "codex-utils-cargo-bin"
 version = "0.0.0"
 dependencies = [
- "assert_cmd",
  "runfiles",
  "thiserror 2.0.20",
 ]
diff --git a/codex-rs/utils/cargo-bin/Cargo.toml b/codex-rs/utils/cargo-bin/Cargo.toml
index a56e5758306..d7788d79c0a 100644
--- a/codex-rs/utils/cargo-bin/Cargo.toml
+++ b/codex-rs/utils/cargo-bin/Cargo.toml
@@ -8,7 +8,6 @@ license.workspace = true
 workspace = true
 
 [dependencies]
-assert_cmd = { workspace = true }
 runfiles = { workspace = true }
 thiserror = { workspace = true }
 
diff --git a/codex-rs/utils/cargo-bin/README.md b/codex-rs/utils/cargo-bin/README.md
index 05af2f34bf0..7537ebdf493 100644
--- a/codex-rs/utils/cargo-bin/README.md
+++ b/codex-rs/utils/cargo-bin/README.md
@@ -9,8 +9,9 @@ behavior consistent in local and remote builds on all platforms. Bazel sets
 Function behavior:
 - `cargo_bin`: reads `CARGO_BIN_EXE_*` environment variables (set by Cargo or
   Bazel) and resolves them via the runfiles manifest when `RUNFILES_MANIFEST_FILE`
-  is present. When not under runfiles, it only accepts absolute paths from
-  `CARGO_BIN_EXE_*` and returns an error otherwise.
+  is present. Outside Bazel, it accepts absolute paths from `CARGO_BIN_EXE_*`,
+  then checks the current Cargo target directory for an already-built binary.
+  Missing binaries return `CargoBinError::NotFound` rather than panicking.
 - `find_resource!`: used by tests to locate fixtures. It chooses the Bazel
   runfiles resolution path when `RUNFILES_MANIFEST_FILE` is set, otherwise it
   falls back to a `CARGO_MANIFEST_DIR`-relative path for Cargo runs.
diff --git a/codex-rs/utils/cargo-bin/src/lib.rs b/codex-rs/utils/cargo-bin/src/lib.rs
index 2cb25a6b17d..881bba9aa12 100644
--- a/codex-rs/utils/cargo-bin/src/lib.rs
+++ b/codex-rs/utils/cargo-bin/src/lib.rs
@@ -35,7 +35,6 @@ pub enum CargoBinError {
 /// In `cargo test`, `CARGO_BIN_EXE_*` env vars are absolute.
 /// In `bazel test`, `CARGO_BIN_EXE_*` env vars are rlocationpaths, intended to be consumed by `rlocation`.
 /// This helper allows callers to transparently support both.
-#[allow(deprecated)]
 pub fn cargo_bin(name: &str) -> Result<PathBuf, CargoBinError> {
     let env_keys = cargo_bin_env_keys(name);
     for key in &env_keys {
@@ -43,28 +42,22 @@ pub fn cargo_bin(name: &str) -> Result<PathBuf, CargoBinError> {
             return resolve_bin_from_env(key, value);
         }
     }
-    match assert_cmd::Command::cargo_bin(name) {
-        Ok(cmd) => {
-            let mut path = PathBuf::from(cmd.get_program());
-            if !path.is_absolute() {
-                path = std::env::current_dir()
-                    .map_err(|source| CargoBinError::CurrentDir { source })?
-                    .join(path);
-            }
-            if path.exists() {
-                Ok(path)
-            } else {
-                Err(CargoBinError::ResolvedPathDoesNotExist {
-                    key: "assert_cmd::Command::cargo_bin".to_owned(),
-                    path,
-                })
-            }
-        }
-        Err(err) => Err(CargoBinError::NotFound {
+
+    let mut fallback_path =
+        std::env::current_exe().map_err(|source| CargoBinError::CurrentExe { source })?;
+    fallback_path.pop();
+    if fallback_path.ends_with("deps") {
+        fallback_path.pop();
+    }
+    fallback_path.push(format!("{name}{}", std::env::consts::EXE_SUFFIX));
+    if fallback_path.is_file() {
+        Ok(fallback_path)
+    } else {
+        Err(CargoBinError::NotFound {
             name: name.to_owned(),
             env_keys,
-            fallback: format!("assert_cmd fallback failed: {err}"),
-        }),
+            fallback: format!("target-directory fallback {fallback_path:?} does not exist"),
+        })
     }
 }
 
diff --git a/codex-rs/utils/cargo-bin/tests/cargo_bin.rs b/codex-rs/utils/cargo-bin/tests/cargo_bin.rs
new file mode 100644
index 00000000000..6a5836954dc
--- /dev/null
+++ b/codex-rs/utils/cargo-bin/tests/cargo_bin.rs
@@ -0,0 +1,48 @@
+use codex_utils_cargo_bin::CargoBinError;
+use std::path::PathBuf;
+
+struct RemoveFileOnDrop(PathBuf);
+
+impl Drop for RemoveFileOnDrop {
+    fn drop(&mut self) {
+        let _ = std::fs::remove_file(&self.0);
+    }
+}
+
+#[test]
+fn missing_binary_returns_not_found_error() {
+    let missing_name = "codex-utils-cargo-bin-missing-test-binary";
+
+    let error = codex_utils_cargo_bin::cargo_bin(missing_name)
+        .expect_err("missing binary lookup should return an error");
+
+    assert!(
+        matches!(&error, CargoBinError::NotFound { name, .. } if name == missing_name),
+        "unexpected error: {error:?}"
+    );
+}
+
+#[test]
+fn target_directory_fallback_finds_existing_binary() {
+    if codex_utils_cargo_bin::runfiles_available() {
+        return;
+    }
+
+    let binary_name = format!("codex-utils-cargo-bin-fallback-test-{}", std::process::id());
+    let mut fallback_path = std::env::current_exe().expect("test executable should be available");
+    fallback_path.pop();
+    if fallback_path.ends_with("deps") {
+        fallback_path.pop();
+    }
+    fallback_path.push(format!("{binary_name}{}", std::env::consts::EXE_SUFFIX));
+    std::fs::write(&fallback_path, []).expect("fallback test binary should be created");
+    let _cleanup = RemoveFileOnDrop(fallback_path.clone());
+
+    let resolved = codex_utils_cargo_bin::cargo_bin(&binary_name)
+        .expect("target-directory fallback should resolve the test binary");
+
+    assert!(
+        resolved == fallback_path,
+        "expected {fallback_path:?}, got {resolved:?}"
+    );
+}
diff --git a/upstream/convergence-guard.json b/upstream/convergence-guard.json
index 82c639484d0..ed9a7a7f491 100644
--- a/upstream/convergence-guard.json
+++ b/upstream/convergence-guard.json
@@ -1,7 +1,7 @@
 {
   "schemaVersion": 1,
   "repository": "openai/codex",
-  "ownershipBaseline": {"base": "b89ce9a2bcedcfddf3a48f387b7912d602d6d87c", "current": "0d05076a80ff5a2dbc5e73311396a080af118b12", "local": "8add494682f7c0674672e8dc5b38a4565cd7629b", "upstream": "4462b9deef211723b781b426f5e5d36a5777115f"},
+  "ownershipBaseline": {"base": "b89ce9a2bcedcfddf3a48f387b7912d602d6d87c", "current": "81753998638d1deb183370c8dfda2bcdaaf23a85", "local": "8add494682f7c0674672e8dc5b38a4565cd7629b", "upstream": "4462b9deef211723b781b426f5e5d36a5777115f"},
   "policy": {"guardedLanes": ["intentionally_owned", "red_manual_review"], "rule": "An owned path may not be absent from the candidate, and may not match the recorded upstream blob, without an explicit waiver.", "sources": {"current_tree": "Owned path in the candidate tree, so owned work created or restored after the baseline is guarded without hand-editing.", "ownership_baseline": "Owned path that already differed from upstream at the pre-anchor local baseline."}},
   "summary": {"guardedLaneCounts": {"intentionally_owned": 446, "red_manual_review": 27}, "guardedPaths": 473, "guardedSourceCounts": {"current_tree": 198, "ownership_baseline": 275}},
   "guardedPaths": [
@@ -457,7 +457,7 @@
     {"baselineBlob": "e63b1a1152a7ace26aff0dba9d731112f5090044", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/README.md", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},
     {"baselineBlob": "2c71fc065155f1717f54f2bdcea58537d6cc7712", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/convergence-contracts.md", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},
     {"baselineBlob": "0b72481f41865505ab1e658c385ab1495f38e7dd", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/convergence-gates.json", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},
-    {"baselineBlob": "8b091a1eb3cbbc7c14d3d39120433a95bbd1154b", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/convergence-guard.json", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},
+    {"baselineBlob": "6bbdc7ca94054c5f86957d55ffa091fb8c246009", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/convergence-guard.json", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},
     {"baselineBlob": "ccccfceeff6dc30fde1cdcadca634579b000b159", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/convergence-policy.json", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},
     {"baselineBlob": "b7066513dca4a330546014704193c02ee2ff7cd9", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/convergence-waivers.json", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},
     {"baselineBlob": "9860ec7791782b1723ea65ebba041232a6d50146", "contracts": ["GOVERNANCE-1"], "lane": "intentionally_owned", "path": "upstream/openai-codex/20dafe20-62fd4103/inventory.json", "reason": "upstream convergence policy, evidence, and enforcement", "source": "current_tree", "upstreamBlob": null},