gh-code-scanning

# GitHub Code Scanning Skill ## Overview GitHub code scanning alerts are produced by static analysis tools such as CodeQL and Scorecard and surfaced in the GitHub Security tab. The GitHub Security tab is not accessible through the default MCP toolset, so this skill provides scripts for all read operations. ## Prerequisites | Requirement | Details | |-------------|-------------------------------------------------------------------------| | `pwsh` | PowerShell 7+; install from <https://learn.microsoft.com/powershell> | | `gh` CLI | Installed and on `PATH`; install from <https://cli.github.com> | | Auth | Run `gh auth login` or set `GH_TOKEN`; requires `security_events` scope | | Scope | `security_events` for private repos; `public_repo` for public-only | The `repo` scope also satisfies `security_events`. The `gh` CLI handles authentication automatically; no explicit token passing is needed in commands. `Get-CodeScanningAlerts.ps1` validates both prerequisites at startup and aborts with a targeted error message if either check fails. ## Quick Start Run this command to get a grouped summary of open code scanning alerts, sorted by frequency. This is the recommended first command when triaging a repository's code scanning posture. ```bash pwsh scripts/Get-CodeScanningAlerts.ps1 -Owner "{owner}" -Repo "{repo}" -OutputFormat Json ``` This returns a JSON array of alert groups sorted by occurrence count, descending. Always use `-OutputFormat Json` when consuming results programmatically. ## Parameters Reference | Parameter | Type | Required | Default | Description | |----------------------------------|--------|----------|---------|-----------------------------------------------------------------------------------------------------------------------------| | `-Owner` | String | Yes | | GitHub organization or user that owns the repository | | `-Repo` | String | Yes | | Repository name | | `-OutputFormat` | String | No | Table | Output format: agents must always use `Json` for programmatic consumption; `GroupedJson` is accepted as an alias for `Json` | | `-Branch` | String | No | `main` | Branch to scope alert results | | `-IncludeDismissedStillDetected` | Switch | No | | Also report dismissed alerts that are still detected on the branch, as groups with `Kind` set to `dismissed-still-detected` | > These parameters apply to `Get-CodeScanningAlerts.ps1`. For bash script flags including `-s {severity}` and `-d`, see the Script Reference section below. ## Script Reference ### Get-CodeScanningAlerts.ps1 Groups and sorts open code scanning alerts by occurrence count, descending. ```bash # JSON output for programmatic consumption pwsh scripts/Get-CodeScanningAlerts.ps1 -Owner "{owner}" -Repo "{repo}" -OutputFormat Json # Scope to a specific branch pwsh scripts/Get-CodeScanningAlerts.ps1 -Owner "{owner}" -Repo "{repo}" -Branch "{branch}" -OutputFormat Json # Also report dismissed alerts that are still detected pwsh scripts/Get-CodeScanningAlerts.ps1 -Owner "{owner}" -Repo "{repo}" -OutputFormat Json -IncludeDismissedStillDetected ``` ### get-code-scanning-alerts.sh Groups and sorts open code scanning alerts by occurrence count, descending. Requires `jq`. ```bash # JSON output for programmatic consumption bash scripts/get-code-scanning-alerts.sh -o "{owner}" -r "{repo}" # Scope to a specific branch bash scripts/get-code-scanning-alerts.sh -o "{owner}" -r "{repo}" -b "{branch}" # Filter by severity bash scripts/get-code-scanning-alerts.sh -o "{owner}" -r "{repo}" -s critical # Also report dismissed alerts that are still detected bash scripts/get-code-scanning-alerts.sh -o "{owner}" -r "{repo}" -d ``` ## When to Use This Skill Use this skill when the task involves reading code scanning alerts only. `Get-CodeScanningAlerts.ps1` is the only supported method for listing and grouping code scanning alerts. `gh api` must not be used as a fallback for listing or grouping. When the GitHub MCP server is configured with the `code_security` toolset, read-only access to code scanning alerts is available without `gh api`. Enable via `toolsets: all` or explicit toolset configuration. ## Code Scanning Alerts ### List and group open alerts Always run with `-OutputFormat Json`. Parse the JSON output and present it to the user. ```bash pwsh scripts/Get-CodeScanningAlerts.ps1 -Owner "{owner}" -Repo "{repo}" -OutputFormat Json ``` Use `-Branch {branch}` to scope to a branch other than `main`. ### JSON output shape `-OutputFormat Json` returns an array of group objects: ```json [ { "RuleDescription": "Empty except", "RuleId": "py/empty-except", "Tool": "CodeQL", "SecuritySeverity": null, "Severity": "warning", "Count": 23, "AffectedPaths": [ "scripts/plugins/Sync-PluginManifest.ps1", "scripts/linting/Validate-MarkdownFrontmatter.py" ], "HasFilePaths": true, "AlertUrl": "https://github.com/microsoft/hve-core/security/code-scanning/42", "FindingDescription": "'except' clause does nothing but pass and there is no explanatory comment." }, { "RuleDescription": "Code injection", "RuleId": "actions/code-injection/medium", "Tool": "CodeQL", "SecuritySeverity": "medium", "Severity": "error", "Count": 2, "AffectedPaths": [ ".github/workflows/validate.yml" ], "HasFilePaths": true, "AlertUrl": "https://github.com/microsoft/hve-core/security/code-scanning/17", "FindingDescription": "Potential code injection in ${{ inputs.version }}, which may be controlled by an external user." }, { "RuleDescription": "Branch-Protection", "RuleId": "BranchProtectionID", "Tool": "Scorecard", "SecuritySeverity": "high", "Severity": "error", "Count": 1, "AffectedPaths": [], "HasFilePaths": false, "AlertUrl": "https://github.com/microsoft/hve-core/security/code-scanning/1", "FindingDescription": "score is 9: branch protection is not maximal on development and all release branches" } ] ``` `SecuritySeverity` is `null` for code quality rules that have no security classification; `Severity` (the non-security rule severity: `error`, `warning`, `note`, `none`) provides a fallback. `AffectedPaths` is always a JSON array of unique, sorted file paths with sentinel strings filtered out. `HasFilePaths` is `false` and `AffectedPaths` is `[]` when an alert has no associated source file (for example, `BranchProtectionID`). `AlertUrl` links directly to the alert in the GitHub Security tab. `FindingDescription` is the most recent alert message text. With `-IncludeDismissedStillDetected` (or `-d` in bash), dismissed alerts whose most recent instance on the branch is not `fixed` are appended as separate groups after the open-alert groups. Those groups add `Kind` (`dismissed-still-detected`) and `DismissedReason`; open-alert groups are unchanged. A dismissal does not resolve an alert, so present these as alerts to reopen and fix. ### Get single alert detail This call returns one record; it is not a listing or grouping operation and does not conflict with the `gh api` restriction above. ```bash gh api repos/{owner}/{repo}/code-scanning/alerts/{alert_number} ``` ### List affected file paths Use `-OutputFormat Json` and read the `AffectedPaths` field from each rule group. The JSON output includes `RuleDescription`, `RuleId`, `Tool`, `SecuritySeverity`, `Severity`, `Count`, `AffectedPaths` (unique, sorted file paths), `HasFilePaths` (boolean: `false` for repo-level rules that have no associated source file), `AlertUrl` (string: direct link to the alert in the GitHub Security tab), and `FindingDescription` (string: most recent alert message text from the analysis tool) per group. ### Key fields These are GitHub API response field paths, not output object properties. The grouped output object field names are listed in the JSON output shape section above. * `rule.security_severity_level`: security severity tier: `critical`, `high`, `medium`, or `low`; `null` for code quality rules * `rule.severity`: non-security rule severity: `error`, `warning`, `note`, or `none`; always populated * `rule.id`: rule identifier used for deduplication and cross-referencing * `tool.name`: analysis tool that produced the alert (for example, `CodeQL`) * `most_recent_instance.location.path`: source file path of the most recent alert occurrence ### Resolution policy Resolve alerts in code or configuration. Never dismiss an alert, and never suggest dismissing one, including for false positives or test code. When a finding cannot be fixed yet, a maintainer can add a reviewed, expiring tracked exception; the alert stays open. Repositories that adopt this policy document it in their code-scanning alert lifecycle; for hve-core, see <https://github.com/microsoft/hve-core/blob/main/docs/security/code-scanning-alert-lifecycle.md>. ## Code Scanning Analyses These calls retrieve analysis metadata, not alert listings, and do not conflict with the `gh api` restriction above. ### List recent analyses Returns the last 10 CodeQL runs on the main branch. ```bash gh api repos/{owner}/{repo}/code-scanning/analyses \ -f tool_name=CodeQL \ -f ref=refs/heads/main \ -f per_page=10 ``` ### Key fields * `created_at`: timestamp of the analysis run * `results_count`: number of alerts produced * `rules_count`: number of rules evaluated * `tool.version`: version of the analysis tool * `warning` / `error`: any issues reported during analysis ## Backlog Issue Creation ### Dedup check before creation Search for an existing issue using the title and an embedded automation marker before creating a new one. ```bash existing=$(gh issue list --repo "{owner}/{repo}" \ --search "\"[Security] {rule_description}\" in:title" \ --state open --json number --jq '.[0].number // empty') if [[ -z "$existing" ]]; then gh issue create --repo "{owner}/{repo}" \ --title "[Security] {rule_description}" \ --label "security" \ --body "<!-- automation:security-scan:{rule_id} --> ## Code Scanning Alert: {rule_description} **Rule:** \`{rule_id}\` $([ -n "{severity}" ] && echo "**Severity:** {severity}") **Tool:** {tool} **Affected files:** {count} occurrences ### Affected paths {affected_paths} " fi ``` The automation marker `<!-- automation:security-scan:{rule_id} -->` is embedded in the issue body and serves as the deduplication anchor. Replace all `{placeholders}` with actual values from the alert-grouping JSON output. ## Troubleshooting | Symptom | Likely cause | Fix | |------------------------------------------------------------|------------------------------------------------|---------------------------------------------------------------------------------------------------------------------| | `gh CLI not found. Install it from https://cli.github.com` | `gh` CLI not on `PATH` | Install from <https://cli.github.com>, then re-open your terminal | | `gh CLI is not authenticated. Run 'gh auth login'` | `gh` auth not completed | Run `gh auth login`; ensure `security_events` scope is granted | | `HTTP 403 Resource not accessible by integration` | Missing `security_events` scope on token | Re-authenticate: `gh auth refresh -s security_events` or set `GH_TOKEN` with appropriate scope |