codex

Optimize unbounded byte scans with memchr (#26265 )

## Summary

This PR adds `memchr` for some low-hanging performance improvements
(namely, in MCP stdio, Ollama streaming, and full message-history
newline counts).

Codex produced the following release benchmarks:

| Operation | Before | After | Speedup |
| --- | ---: | ---: | ---: |
| MCP 1 MiB chunked line | 2.172 s | 3.984 ms | 545x |
| Ollama 1 MiB chunked line | 1.673 s | 2.790 ms | 600x |
| Count newlines in 10 MiB history | 132.83 ms | 20.05 ms | 6.6x |

With a "real" MCP setup (`ExecutorStdioServerLauncher` started a Python
MCP server, completed `initialize`, requested `tools/list`, and
deserialized a 1 MiB tool description over newline-delimited stdio),
it's about 16x faster end-to-end:

| Branch | 50 calls | Per call |
| --- | ---: | ---: |
| `main` | 862.53 ms | 17.25 ms |
| this branch | 53.89 ms | 1.08 ms |

`memchr` is already in our dependency tree and extremely widely used for
this kind of optimized scanning.

Charlie Marsh · 2026-06-04 09:53:08 -04:00

7da4af622f

remove temporary ownership re-exports (#16626 )

Stacked on #16508.

This removes the temporary `codex-core` / `codex-login` re-export shims
from the ownership split and rewrites callsites to import directly from
`codex-model-provider-info`, `codex-models-manager`, `codex-api`,
`codex-protocol`, `codex-feedback`, and `codex-response-debug-context`.

No behavior change intended; this is the mechanical import cleanup layer
split out from the ownership move.

---------

Co-authored-by: Codex <noreply@openai.com>

Ahmed Ibrahim · 2026-04-03 00:33:34 -07:00

af8a9d2d2b

chore: nuke chat/completions API (#10157 )

jif-oai · 2026-02-03 11:31:57 +00:00

d2394a2494

ollama: default to Responses API for built-ins (#8798 )

This is an alternate PR to solving the same problem as
<https://github.com/openai/codex/pull/8227>.

In this PR, when Ollama is used via `--oss` (or via `model_provider =
"ollama"`), we default it to use the Responses format. At runtime, we do
an Ollama version check, and if the version is older than when Responses
support was added to Ollama, we print out a warning.

Because there's no way of configuring the wire api for a built-in
provider, we temporarily add a new `oss_provider`/`model_provider`
called `"ollama-chat"` that will force the chat format.

Once the `"chat"` format is fully removed (see
<https://github.com/openai/codex/discussions/7782>), `ollama-chat` can
be removed as well

---------

Co-authored-by: Eric Traut <etraut@openai.com>
Co-authored-by: Michael Bolin <mbolin@openai.com>

Devon Rifkin · 2026-01-13 09:51:41 -08:00

fe03320791

make model optional in config (#7769 )

- Make Config.model optional and centralize default-selection logic in
ModelsManager, including a default_model helper (with
codex-auto-balanced when available) so sessions now carry an explicit
chosen model separate from the base config.
- Resolve `model` once in `core` and `tui` from config. Then store the
state of it on other structs.
- Move refreshing models to be before resolving the default model

Ahmed Ibrahim · 2025-12-10 11:19:00 -08:00

cb9a189857

LM Studio OSS Support (#2312 )

## Overview

Adds LM Studio OSS support. Closes #1883


### Changes
This PR enhances the behavior of `--oss` flag to support LM Studio as a
provider. Additionally, it introduces a new flag`--local-provider` which
can take in `lmstudio` or `ollama` as values if the user wants to
explicitly choose which one to use.

If no provider is specified `codex --oss` will auto-select the provider
based on whichever is running.

#### Additional enhancements 
The default can be set using `oss-provider` in config like:

```
oss_provider = "lmstudio"
```

For non-interactive users, they will need to either provide the provider
as an arg or have it in their `config.toml`

### Notes
For best performance, [set the default context
length](https://lmstudio.ai/docs/app/advanced/per-model) for gpt-oss to
the maximum your machine can support

---------

Co-authored-by: Matt Clayton <matt@lmstudio.ai>
Co-authored-by: Eric Traut <etraut@openai.com>

rugvedS07 · 2025-11-17 11:49:09 -08:00

837bc98a1d

Use assert_matches (#4756 )

assert_matches is soon to be in std but is experimental for now.

pakrym-oai · 2025-10-05 21:12:31 +00:00

5c42419b02

chore: clippy on redundant closure (#4058 )

Add redundant closure clippy rules and let Codex fix it by minimising
FQP

jif-oai · 2025-09-22 19:30:16 +00:00

be366a31ab

chore: upgrade to Rust 1.89 (#2465 )

Codex created this PR from the following prompt:

> upgrade this entire repo to Rust 1.89. Note that this requires
updating codex-rs/rust-toolchain.toml as well as the workflows in
.github/. Make sure that things are "clippy clean" as this change will
likely uncover new Clippy errors. `just fmt` and `cargo clippy --tests`
are sufficient to check for correctness

Note this modifies a lot of lines because it folds nested `if`
statements using `&&`.

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/2465).
* #2467
* __->__ #2465

Michael Bolin · 2025-08-19 13:22:02 -07:00

50c48e88f5

Added allow-expect-in-tests / allow-unwrap-in-tests (#2328 )

This PR:
* Added the clippy.toml to configure allowable expect / unwrap usage in
tests
* Removed as many expect/allow lines as possible from tests
* moved a bunch of allows to expects where possible

Note: in integration tests, non `#[test]` helper functions are not
covered by this so we had to leave a few lingering `expect(expect_used`
checks around

Parker Thompson · 2025-08-14 17:59:01 -07:00

a075424437

fix: when using --oss, ensure correct configuration is threaded through correctly (#1859 )

This PR started as an investigation with the goal of eliminating the use
of `unsafe { std::env::set_var() }` in `ollama/src/client.rs`, as
setting environment variables in a multithreaded context is indeed
unsafe and these tests were observed to be flaky, as a result.

Though as I dug deeper into the issue, I discovered that the logic for
instantiating `OllamaClient` under test scenarios was not quite right.
In this PR, I aimed to:

- share more code between the two creation codepaths,
`try_from_oss_provider()` and `try_from_provider_with_base_url()`
- use the values from `Config` when setting up Ollama, as we have
various mechanisms for overriding config values, so we should be sure
that we are always using the ultimate `Config` for things such as the
`ModelProviderInfo` associated with the `oss` id

Once this was in place,
`OllamaClient::try_from_provider_with_base_url()` could be used in unit
tests for `OllamaClient` so it was possible to create a properly
configured client without having to set environment variables.

Michael Bolin · 2025-08-05 13:55:32 -07:00

d365cae077

fix: correct spelling error that sneaked through (#1855 )

I ended up force-pushing https://github.com/openai/codex/pull/1848
because CI jobs were not being triggered after updating the PR on
GitHub, so this spelling error sneaked through.

Michael Bolin · 2025-08-05 11:39:30 -07:00

9f91b3da24

Introduce --oss flag to use gpt-oss models (#1848 )

This adds support for easily running Codex backed by a local Ollama
instance running our new open source models. See
https://github.com/openai/gpt-oss for details.

If you pass in `--oss` you'll be prompted to install/launch ollama, and
it will automatically download the 20b model and attempt to use it.

We'll likely want to expand this with some options later to make the
experience smoother for users who can't run the 20b or want to run the
120b.

Co-authored-by: Michael Bolin <mbolin@openai.com>

easong-openai · 2025-08-05 11:31:11 -07:00

9285350842

13 Commits