Review code changes for security

Use a security change review when you need evidence about regressions introduced by one Git-backed change set. The workflow reviews every changed source-like file and directly supporting code without turning the task into a general repository audit.

If you want to scan a full repository instead of a specific change, see Run a security scan.

Run a manual review

For uncommitted changes, send:

Use $codex-security:security-diff-scan to review my current uncommitted changes for security regressions.

For a commit or branch range, identify both ends when needed:

Use $codex-security:security-diff-scan to review the changes from origin/main to HEAD for security regressions. Focus on authentication, authorization, input handling, filesystem access, network requests, and secrets.

You can also name a pull request when its base and head revisions are available in the local checkout.

Confirm the change in setup

Confirm Scan type is Changes.
Confirm the checked-out Codebase, Current branch, and Last commit.
Under Changes to review, choose:
- Uncommitted changes for the current working tree.
- The latest commit for a single-commit review.
- A base and head revision for a branch or pull-request range.
Confirm that the summary describes the change you intended to review.
Select Start scan.

The workflow doesn't check out another branch or change the selected working tree. If a requested revision isn't available locally, fetch it before the review or provide a locally available base and head.

Act on findings

After reviewing the results, fix and verify an accepted finding or export and track findings.

Automate reviews in CI/CD

Run the same $codex-security:security-diff-scan skill from CI when the runner can invoke the Codex CLI without interaction. The runner must already have Codex Security installed in the CODEX_HOME used by codex exec. A fresh runner doesn't have marketplace plugins installed by default, and openai/codex-action doesn't install the plugin.

Before running the scan:

Provision Codex Security in the runner's CODEX_HOME.
Check out the exact base and head revisions with their Git history.
Set the runner's platform temporary directory, such as TMPDIR, to a writable artifact location. The diff-scan workflow reviews the checkout without changing it, but it writes its sealed scan bundle and final report outside the repository.
Start with advisory results. Review scan quality and runtime before making the job a required check.

Then invoke the plugin explicitly:

export CODEX_HOME=/path/to/provisioned-codex-home
export TMPDIR=/path/to/writable/temp

codex exec \
  --sandbox workspace-write \
  --output-last-message "$TMPDIR/codex-security-review.md" \
  'Use $codex-security:security-diff-scan to review changes from <base-revision> to <head-revision> for security regressions. Do not modify the checkout. Return the final report path, findings summary, reviewed surfaces, deferred coverage, and open questions.'

Archive the generated scan bundle and final report, then publish the Markdown summary through your CI/CD system. If you use openai/codex-action, point its codex-home input at the same provisioned directory and pass the skill prompt above. The action can install and run the Codex CLI, but plugin provisioning is a separate prerequisite.

For API-key handling, sandbox controls, fork protections, and a GitHub Actions workflow, see the Codex GitHub Action guide.

security/plugin/code-changes.md +34 −104

52 52

53## Automate reviews in CI/CD53## Automate reviews in CI/CD

54 54

~~55You can run a change review from any CI/CD system that can check out the target~~55Run the same `$codex-security:security-diff-scan` skill from CI when the runner

~~56revisions and invoke the Codex CLI without interaction. Resolve the exact base~~56can invoke the Codex CLI without interaction. The runner must already have

~~57and head revisions, use a read-only sandbox, save the Markdown result, and~~57Codex Security installed in the `CODEX_HOME` used by `codex exec`. A fresh

~~58publish it through your CI/CD system.~~58runner doesn't have marketplace plugins installed by default, and

59 59`openai/codex-action` doesn't install the plugin.

~~60### GitHub Actions example~~60

61 61Before running the scan:

~~62The following GitHub Actions workflow is one implementation of this pattern. It~~62

~~63uses `openai/codex-action` to install the Codex CLI and run `codex exec` with a~~631. Provision Codex Security in the runner's `CODEX_HOME`.

~~64read-only sandbox. It produces a Markdown review for every in-scope pull~~642. Check out the exact base and head revisions with their Git history.

~~65request.~~653. Set the runner's platform temporary directory, such as `TMPDIR`, to a

66 66 writable artifact location. The diff-scan workflow reviews the checkout

~~67Before you add the workflow:~~67 without changing it, but it writes its sealed scan bundle and final report

68 68 outside the repository.

~~691. Create an `OPENAI_API_KEY` repository or organization secret.~~694. Start with advisory results. Review scan quality and runtime before making

~~702. Save the workflow as `.github/workflows/codex-security-review.yml`.~~70 the job a required check.

~~713. Start with advisory comments. Tune the prompt and review the results before~~71

~~72 making the workflow a required check.~~72Then invoke the plugin explicitly:

73 73

~~74```yaml~~74```bash

~~75name: Codex Security pull request review~~75export CODEX_HOME=/path/to/provisioned-codex-home

76 76export TMPDIR=/path/to/writable/temp

~~77on:~~77

~~78 pull_request:~~78codex exec \

~~79 types: [opened, synchronize, reopened]~~79 --sandbox workspace-write \

80 80 --output-last-message "$TMPDIR/codex-security-review.md" \

~~81jobs:~~81 'Use $codex-security:security-diff-scan to review changes from <base-revision> to <head-revision> for security regressions. Do not modify the checkout. Return the final report path, findings summary, reviewed surfaces, deferred coverage, and open questions.'

~~82 security_review:~~

~~83 if: github.event.pull_request.head.repo.full_name == github.repository~~

~~84 runs-on: ubuntu-latest~~

~~85 permissions:~~

~~86 contents: read~~

~~87 outputs:~~

~~88 final_message: ${{ steps.run_codex.outputs.final-message }}~~

~~90 steps:~~

~~91 - uses: actions/checkout@v5~~

~~92 with:~~

~~93 ref: refs/pull/${{ github.event.pull_request.number }}/merge~~

~~94 fetch-depth: 0~~

~~95 persist-credentials: false~~

~~97 - name: Fetch pull request refs~~

~~98 env:~~

~~99 PR_BASE_REF: ${{ github.event.pull_request.base.ref }}~~

100 PR_NUMBER: ${{ github.event.pull_request.number }}

101 run: |

102 git fetch --no-tags origin \

103 "$PR_BASE_REF" \

104 "+refs/pull/$PR_NUMBER/head"

~~105~~

106 - name: Run Codex Security review

107 id: run_codex

108 uses: openai/codex-action@v1

109 with:

110 openai-api-key: ${{ secrets.OPENAI_API_KEY }}

111 sandbox: read-only

112 output-file: codex-security-review.md

113 prompt: |

114 Review the pull request changes from

115 ${{ github.event.pull_request.base.sha }} to

116 ${{ github.event.pull_request.head.sha }} for security regressions.

~~117~~

118 Focus on authentication, authorization, input handling, filesystem

119 access, network requests, secrets, and changes to shared security

120 controls. Return a concise Markdown review with affected paths and

121 lines, evidence, impact, and remediation guidance. If there are no

122 findings, summarize the security-sensitive surfaces reviewed and

123 any coverage gaps.

~~124~~

125 - name: Upload the review

126 uses: actions/upload-artifact@v4

127 with:

128 name: codex-security-review

129 path: codex-security-review.md

~~130~~

131 post_review:

132 needs: security_review

133 if: needs.security_review.outputs.final_message != ''

134 runs-on: ubuntu-latest

135 permissions:

136 issues: write

137 pull-requests: write

~~138~~

139 steps:

140 - name: Post the review

141 uses: actions/github-script@v7

142 env:

143 CODEX_FINAL_MESSAGE: ${{ needs.security_review.outputs.final_message }}

144 with:

145 github-token: ${{ github.token }}

146 script: |

147 await github.rest.issues.createComment({

148 owner: context.repo.owner,

149 repo: context.repo.repo,

150 issue_number: context.payload.pull_request.number,

151 body: process.env.CODEX_FINAL_MESSAGE,

152 });

153```82```

154 83

155This workflow checks out the pull request merge commit and fetches the base and84Archive the generated scan bundle and final report, then publish the Markdown

156head refs so Codex can resolve the exact change. The security review job has85summary through your CI/CD system. If you use `openai/codex-action`, point its

157read-only repository permissions. A separate job receives permission to post86`codex-home` input at the same provisioned directory and pass the skill prompt

158the final Markdown review, but it never receives the OpenAI API key.87above. The action can install and run the Codex CLI, but plugin provisioning is

88a separate prerequisite.

159 89

160For action inputs, privilege controls, and troubleshooting, see the [Codex90For API-key handling, sandbox controls, fork protections, and a GitHub Actions

161GitHub Action guide](https://developers.openai.com/codex/github-action).91workflow, see the [Codex GitHub Action guide](https://developers.openai.com/codex/github-action).