docs: Add GitLab CLI agent integration doc (#2103)

packages/web/src/content/docs/docs/gitlab.mdx

@@ -0,0 +1,132 @@
+---
+title: GitLab
+description: Use opencode in GitLab issues and merge requests
+---
+
+opencode integrates with your GitLab workflow.
+Mention `@opencode` in a comment, and opencode will execute tasks within your GitLab CI pipeline.
+
+---
+
+## Features
+
+- **Triage issues**: Ask opencode to look into an issue and explain it to you.
+- **Fix and implement**: Ask opencode to fix an issue or implement a feature.
+  It will work create a new branch and raised a merge request with the changes.
+- **Secure**: opencode runs on your GitLab runners.
+
+---
+
+## Setup
+
+Refer to the [GitLab CLI agents docs](https://docs.gitlab.com/user/duo_agent_platform/agent_assistant/)
+for detailed setup instructions.
+
+Here is an example of the agent configuration:
+
+```yaml
+image: node:22-slim
+commands:
+  - echo "Installing opencode"
+  - npm install --global opencode-ai
+  - echo "Installing glab"
+  - export GITLAB_TOKEN=$GITLAB_TOKEN_OPENCODE
+  - apt-get update --quiet && apt-get install --yes curl wget gpg git && rm --recursive --force /var/lib/apt/lists/*
+  - curl --silent --show-error --location "https://raw.githubusercontent.com/upciti/wakemeops/main/assets/install_repository" | bash
+  - apt-get install --yes glab
+  - echo "Configuring glab"
+  - echo $GITLAB_HOST
+  - echo "Creating opencode auth configuration"
+  - mkdir --parents ~/.local/share/opencode
+  - |
+    cat > ~/.local/share/opencode/auth.json << EOF
+    {
+      "anthropic": {
+        "type": "api",
+        "key": "$ANTHROPIC_API_KEY"
+      }
+    }
+    EOF
+  - echo "Configuring git"
+  - git config --global user.email "[email protected]"
+  - git config --global user.name "Opencode"
+  - echo "Testing glab"
+  - glab issue list
+  - echo "Running Opencode"
+  - |
+    opencode run "
+    You are an AI assistant helping with GitLab operations.
+
+    Context: $AI_FLOW_CONTEXT
+    Task: $AI_FLOW_INPUT
+    Event: $AI_FLOW_EVENT
+
+    Please execute the requested task using the available GitLab tools.
+    Be thorough in your analysis and provide clear explanations.
+
+    <important>
+    Please use the glab CLI to access data from GitLab. The glab CLI has already been authenticated. You can run the corresponding commands.
+
+    If you are asked to summarise an MR or issue or asked to provide more information then please post back a note to the MR/Issue so that the user can see it.
+    You don't need to commit or push up changes, those will be done automatically based on the file changes you make.
+    </important>
+    "
+  - git checkout --branch $CI_WORKLOAD_REF origin/$CI_WORKLOAD_REF
+  - echo "Checking for git changes and pushing if any exist"
+  - |
+    if ! git diff --quiet || ! git diff --cached --quiet || [ --not --zero "$(git ls-files --others --exclude-standard)" ]; then
+      echo "Git changes detected, adding and pushing..."
+      git add .
+      if git diff --cached --quiet; then
+        echo "No staged changes to commit"
+      else
+        echo "Committing changes to branch: $CI_WORKLOAD_REF"
+        git commit --message "Codex changes"
+        echo "Pushing changes up to $CI_WORKLOAD_REF"
+        git push https://gitlab-ci-token:$GITLAB_TOKEN@$GITLAB_HOST/gl-demo-ultimate-dev-ai-epic-17570/test-java-project.git $CI_WORKLOAD_REF
+        echo "Changes successfully pushed"
+      fi
+    else
+      echo "No git changes detected, skipping push"
+    fi
+variables:
+  - ANTHROPIC_API_KEY
+  - GITLAB_TOKEN_OPENCODE
+  - GITLAB_HOST
+```
+
+---
+
+## Examples
+
+Here are some examples of how you can use opencode in GitLab.
+
+- **Explain an issue**
+
+  Add this comment in a GitLab issue.
+
+  ```
+  @opencode explain this issue
+  ```
+
+  opencode will read the issue and reply with a clear explanation.
+
+- **Fix an issue**
+
+  In a GitLab issue, say:
+
+  ```
+  @opencode fix this
+  ```
+
+  opencode will create a new branch, implement the changes, and open a merge request with the changes.
+
+- **Review merge requests**
+
+  Leave the following comment on a GitLab merge request.
+
+  ```
+  @opencode review this merge request
+  ```
+
+  opencode will review the merge request and provide feedback.