Failing to use apply_patch tool

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• #16397

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Potential duplicates detected. Please review them and close your issue if it is a duplicate. * Non GPT model from custom provider cannot edit file using apply_patch, also cannot use multi_tool_use.parallel  #16397 _Powered by Codex Action_

Not duplicate. Using GPT model and apply_patch tool keeps failing consistently, regardless of parallel tool use.

Further notes from the investigation:

› List tools you are available to call, do you have tool that can apply patch?

• Here’s the full set of tools I can invoke in this session:

| Tool | What it does |
|------|--------------|
| exec_command | Run a shell command in the workspace. |
| write_stdin | Send input to an interactive exec session. |
| apply_patch | Apply a unified‑diff patch to a tracked file in the repository. |
| update_plan | Update a checklist/plan (used only in Plan mode). |
| request_user_input | Ask the user a question (only available while in Plan mode). |
| spawn_agent | Create a new agent for parallel or delegated work. |
| send_input | Send messages to an existing agent. |
| resume_agent | Re‑open a closed agent. |
| wait_agent | Wait for an agent to finish its task. |
| close_agent | Close an agent when finished. |
| view_image | Display a local image file in the UI. |

Yes, I have an apply_patch tool that lets me modify source files directly.

› can you let me know how to use apply_patch tool?

• ### Using the apply_patch tool

The apply_patch command lets you edit a tracked file by applying a unified diff (the same format that git apply uses).

#### 1. Build the patch text

Write a diff in unified format:

* Begin Patch
* Update File: src/main.rs
@@

• transformation: String,
• transformation: TransformMode,

*** End Patch

• Begin Patch and End Patch delimit the whole patch.
• *** Update File: <path> tells which file to modify.
• The lines starting with @@ are the hunk header – they show the context of the change.
• Lines beginning with - are removed, lines beginning with + are added.

#### 2. Call the tool

{
"cmd": [
"apply_patch",
" Begin Patch\n Update File: src/main.rs\n@@\n- transformation: String,\n+ transformation: TransformMode,\n*** End Patch"
]
}

#### 3. What happens

• The tool checks that the file is under the current working directory (or a writable root).
• It applies the diff atomically.
• If any part of the patch does not match the current file (e.g., the context lines differ), the tool fails with an error.

#### 4. Common pitfalls

| Problem | Fix |
|---------|-----|
| Patch does not apply | Verify the context lines (@@) match exactly, including whitespace. |
| Missing Begin Patch / End Patch | These markers are required; otherwise the tool will reject it. |
| Editing a file outside writable roots | You’ll need to request escalated permission or move the file into an allowed directory. |

#### 5. Quick example

{
"cmd": [
"apply_patch",
" Begin Patch\n Update File: src/main.rs\n@@\n- transformation: String,\n+ transformation: TransformMode,\n*** End Patch"
]
}

This will replace the transformation: String line with transformation: TransformMode.

That’s all you need to know! Feel free to give me a patch and I’ll apply it.

› use apply_patch tool to apply the following patch:
* Begin Patch
* Update File: src/main.rs
@@

• transformation: String,
• transformation: TransformMode,

*** End Patch

• We need to apply patch. Use apply_patch tool. Ensure correct formatting: the JSON command expects array of strings? The function signature: exec_command? No, apply_patch. The tool is apply_patch.
We need to call with JSON: {"cmd": ["apply_patch", "..."]}. Provide patch string. Ensure we escape newlines properly.

Let's call apply_patch.

• It says cannot find tool named apply_patch. Wait, earlier in instruction: "Use the apply_patch tool to edit files". That is a tool name. But in this environment, maybe it's apply_patch? The
function names earlier: In the tool list, we have "apply_patch" as a tool. But in our call to functions.apply_patch, maybe the function is named "apply_patch". We used correct. But error says
cannot find tool with name apply_patch. Perhaps the function is named "apply_patch" but we need to call via functions.apply_patch? We did. It returned error. Maybe the tool is not available because
of sandbox restrictions or we need to use exec_command? But spec says apply_patch is a tool. Might be that the environment hasn't loaded it or it's not accessible. In earlier conversation, we used
apply_patch? Not yet. So maybe the tool name is "apply_patch" but we need to call with {"command": ["apply_patch", "..."]}? Actually the function is apply_patch defined in "functions" namespace. We
called correctly.

But error: Cannot find tool with name apply_patch. That means the function is not recognized. Maybe the function's name is apply_patch but we must call via functions.apply_patch. We did. But the
system says cannot find tool. Maybe we mis-specified cmd array: The first element should be the patch content? Wait, maybe the tool expects "apply_patch" command like git apply. But here we pass
patch content as second element. The tool may require just patch string, not command name. Let's check spec: apply_patch tool: {"command":["apply_patch","*** Begin Patch\n..."]}. So first element
is "apply_patch". That matches. But error says cannot find tool. Maybe the correct function name is apply_patch but we used "apply_patch" incorrectly? Wait, earlier we saw the tool list includes
apply_patch: ... But maybe the function is named "apply_patch" but we used wrong? Actually we called functions.apply_patch, which matches. But error says cannot find tool with name apply_patch.
Might be due to missing "apply_patch" function in the environment? Maybe we need to call via functions.exec_command with command "apply_patch"? But spec says apply_patch is a separate tool.

Let's check if other tools exist: We earlier called exec_command. That worked. But apply_patch not found.

Let's search for "apply_patch" in repo to see if it's defined.

• We misused exec_command; need to pass array of strings. But not needed.

Maybe the environment only has exec_command and not apply_patch. The earlier spec mention "apply_patch" but maybe not implemented. Let's see if there's a tool named "patch". Search for patch.Let's
list available tools by reading the spec? The earlier tool list includes apply_patch. But maybe not loaded.

Given this, perhaps we should use exec_command to run git apply? But we don't have git. But can patch file manually using sed or echo.

But the instructions: "If completing the user's task requires writing or modifying files, your code and final answer should follow these coding guidelines... Use the apply_patch tool to edit files
(NEVER try applypatch or apply-patch)". So we should use apply_patch. But it's not available.

Maybe the tool name is apply_patch but we need to call via "functions.apply_patch" exactly. We did that, got error.

Let's try calling apply_patch without the array? Possibly it's just a string. Let's check spec: The tool type is apply_patch with JSON param { "command": ["apply_patch", "..."] }. So we should pass
array. We did.

But error: "Cannot find tool with name apply_patch." Means the function is not loaded. Could be that we need to use "apply_patch" as a command string inside exec_command? But spec says apply_patch
tool.

Maybe the correct name is "applypatch"? Let's search for that.We cannot search because tool not available.

Maybe we should use exec_command with apply_patch command? But not likely.

Let's examine the environment: maybe apply_patch is not supported. In such case, we might need to manually edit file using apply_patch? But spec says use apply_patch. If not available, maybe we
cannot patch.

Given this mismatch, perhaps the environment does not have apply_patch. Let's attempt to use exec_command with apply_patch? But we don't know.

We can manually patch file using a simple echo with redirection. But that may not be permitted? We can run sed -i to edit file.

But instructions: "Use the apply_patch tool to edit files (NEVER try applypatch or apply-patch)". But if not available, maybe we cannot comply.

Let's check if the tool apply_patch exists by listing all tools. The environment may not expose list.

But maybe the correct function name is apply_patch but we need to call as "apply_patch" not "functions.apply_patch"? The earlier pattern: For exec_command we called functions.exec_command. So
apply_patch should be similar.

But error says cannot find tool. Maybe the function name is apply_patch but we need to use "apply_patch" with capital? No.

Maybe the environment uses "applypatch" not "apply_patch". Let's try that.

• - Update File: src/main.rs\n@@\n- transformation: String,\n+ transformation: TransformMode,\n*** End Patch"]
}

But still exec_command expects array of strings, that's fine. But the command applypatch may not exist.

Let's try:We need to decide next. Perhaps the tool is missing; we can patch manually via sed or echo.

We can use apply_patch? But not available. The instruction says to use apply_patch. But we cannot. In that case, maybe we should explain inability.

Thus I will respond: "I don't have apply_patch available; can use exec_command with patch via sed."

• I’m sorry, but the current sandbox does not expose an apply_patch tool.
To modify a file you can either:

1. Use the exec_command tool and run a command that edits the file (e.g., sed -i …, ed, or a small script).
2. Write the file manually by creating a new patch string and piping it to tee or cat >.

If you’d like me to apply the change, let me know which method you prefer and I’ll generate the appropriate command.

• Context compacted

• Context compacted

Experiencing this issue since 0.118.0 on Ubuntu 24.04 using models from OpenAI via login/oauth.

Getting this issue after upgrading from 0.118.0 to 0.121.0 on Ubuntu 24.04 using gpt-5.4 xhigh fast. Confirmed reverting to 0.118.0 resolves the issue. Example trace on 0.121.0:

• apply_patch is still rejecting the paths, so I’m checking the patch tool’s expected path base before I continue. Once that’s clear I’ll land the code and run the unit tests.

• Ran pwd && ls && test -d src/dms/tests/EdFi.DataManagementService.Tests.E2E/Management && echo exists
└ /home/brad/work/dms-root/Data-Management-Service
AGENTS.md
… +30 lines
test-run.log
exists

• I need to figure out if I can use the tool to apply a patch when the current base is unknown. Maybe using an absolute path will help, but I'm wondering if the apply_patch function can't create a new file while trying
to update an existing one. I should check if the error about the missing file is due to a syntax issue or a problem with the patch parser. I could also consider using exec_command with a here-doc approach, but
instructions suggest sticking with apply_patch. I should inspect the patch grammar too.

Testing patch application

I'm considering breaking the patch into smaller ones, tackling one file at a time. It might be smart to add a small file in the repo root just for testing, but I'm hesitant to create any stray files. I could focus on
patching an existing file first, like SetupHooks, to see if that works. The error might mean that the initial add file path isn't found, so I’ll try updating an existing file with a simple line addition. This way, I
can always amend later.

• Edited src/dms/tests/EdFi.DataManagementService.Tests.E2E/Hooks/SetupHooks.cs (+0 -0)

✘ Failed to apply patch

• I see I'm getting an error about "No such file or directory," and I'm wondering if it's related to the apply_patch binary itself. The tool returned an execution error, which might mean it's trying to access the patch
file path incorrectly. Maybe I can use commentary to=functions.exec_command to run commands like which apply_patch or type apply_patch. I’m curious if the shell has the same helper available, but I think it's more
likely that it doesn't. Let's dig deeper!

• Ran type apply_patch || which apply_patch || command -v apply_patch
└ apply_patch is /home/brad/.codex/tmp/arg0/codex-arg0qSOypy/apply_patch

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

• The dedicated patch tool is failing even on an existing file. I’m falling back to the same apply_patch helper through the shell in the repo worktree so the edits still go in as structured patches.

• Ran apply_patch --help
└ Invalid patch: The first line of the patch must be '*** Begin Patch'

• I’m recognizing that the apply_patch command exists and functions as needed. I’ll use exec_command to pipe in the patch using heredoc. It’s important to avoid using cat to create files, but using the apply_patch
command in shell is fine. I’m wondering if I should combine changes into one command, potentially using here-doc for the patch. I’ll need to craft the patch carefully and then run csharpier, using exec_command with
apply_patch in a here-doc.

• Edited 3 files (+358 -0)
└ src/dms/tests/EdFi.DataManagementService.Tests.E2E/Hooks/SetupHooks.cs (+5 -0)

...

✘ Failed to apply patch

• I’m wondering if I can update the exact same line in the existing file. Would doing a no-op be accepted? Hmm, the patch might not apply if there's no change. Maybe I can test path resolution with a harmless tweak on a
temporary dummy file, but I'm stuck since I can't create one without a patch. I should think about whether the tool can update AGENTS.md, but I'm unsure about line endings or file paths depending on the repository
structure.

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

• The built-in patch tool still isn’t resolving repo-relative paths from this workspace. I’m trying the parent-root form next; once it accepts paths, I’ll apply the full change in one patch.

• Edited src/dms/tests/EdFi.DataManagementService.Tests.E2E/Hooks/SetupHooks.cs (+0 -0)

✘ Failed to apply patch

• I’m noticing some strange behavior with path variants. When I used the wrong path, it gave a verification failure, but the correct path results in a generic error. Maybe the parser can’t handle a long path? It could
also be that the tool can’t locate the patch if it’s a no-op. Even though the simple patch updates the file without any changes, that might result in execution errors. I should try a small change with an existing file
to test the path validity.

Deciding on a patch approach

Since I really need to make an actual change, it seems better to apply a real patch on SetupHooks. I think I should go with a smaller, more straightforward patch this time. It’ll be easier to manage and test. This way,
I can ensure that the changes will be effective and lead to the desired outcome without complicating things unnecessarily. Let’s implement that smaller patch!

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

• The path base is fine. The earlier probe patch was effectively a no-op, which explains the bad signal. I’m applying the real edits now in smaller pieces so I can isolate any patch-format issue cleanly.

...

✘ Failed to apply patch

• I’m considering whether the actual apply_patch script needs to run from the repo root. It might not be useful if the tool isn’t functional. I could try using exec_command to modify files through ed or perl, but there’s
a warning about this, possibly related to how the user context is inserted. The developer advises using apply_patch for manual edits, though it seems there’s no strict enforcement or automatic logging of the warning.
Since apply_patch is broken, I think I need to proceed cautiously with edits and document everything in the final output.

Also experiencing the same apply patch failures after updating to 0.121.0 on WSL using gpt-5.4 xhigh fast.

✘ Failed to apply patch

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

• The first patch attempt failed on path resolution. I’m retrying against the repo-relative path ...

✘ Failed to apply patch

• Ran pwd && ls -d ...

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

• I hit an apply_patch path-resolution issue even though the file exists. I’m narrowing that down with a minimal patch first, then I’ll apply the instrumentation once the
patch tool is behaving.

• Edited ... (+0 -0)

✘ Failed to apply patch

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

• I confirmed the patch tool is rooted at ..... The large patch likely failed because of patch parsing, not the file location. I’m applying the
instrumentation in smaller hunks now.

✘ Failed to apply patch

─ Worked for 1m 03s ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

• The patch wrapper is failing both directly and through the shell binary. I’m switching to a deterministic one-shot file rewrite so we can still get the instrumentation

For Linux environments, please consider using RAP:
https://github.com/francescobianco/rap

It provides a more reliable patch application workflow and helps avoid issues related to apply_patch behavior and sandbox/environment inconsistencies.