Pr Preflight

pr-preflight skill

Single Responsibility: Parse PR URL + validate environment. Return structured JSON.

Input

Receive PR URL string. Example: https://bitbucket.org/workspace/repo/pull-requests/123

What you do

1. Parse URL

Supported patterns (regex):

github.com/<org>/<repo>/pull/<id>
gitlab.com/<group>[/<subgroup>...]/<repo>/-/merge_requests/<id>
bitbucket.org/<workspace>/<repo_slug>/pull-requests/<id>

Extract: domain, workspace (org/group), repo_slug, pr_number.

2. Identify provider

"github"    in domain → provider="github",    mcp_server="github-mcp-server"
"gitlab"    in domain → provider="gitlab",    mcp_server="gitlab-mcp-server"
"bitbucket" in domain → provider="bitbucket", mcp_server="mcp-server-atlassian-bitbucket"

3. Validate environment

Use Bash tool:

• which git — confirm git available
• git config --global user.name and user.email — get reviewer identity
• MCP availability: check tool list for provider-specific tool name:
  • bitbucket → look for mcp__bitbucket__bb_get
  • github → look for mcp__github__ prefix
  • gitlab → look for mcp__gitlab__ prefix
  • If tool not found: set mcp_available: false, add warning MCP_SERVER_NOT_CONFIGURED

Output (JSON only)

status enum: "SUCCESS" | "BLOCK" | "FAILURE" — see Status rules.

{
  "agent_name": "pr-preflight",
  "version": "1.0",
  "status": "SUCCESS",
  "parsed_data": {
    "domain": "bitbucket.org",
    "provider": "bitbucket",
    "workspace": "acme",
    "repo_slug": "web-app",
    "pr_number": 123,
    "mcp_server": "mcp-server-atlassian-bitbucket"
  },
  "environment": {
    "git_available": true,
    "git_version": "2.40.0",
    "mcp_available": true,
    "git_identity": {
      "name": "John Doe",
      "email": "john@example.com"
    }
  },
  "errors": []
}

Error cases

Status rules:

• BLOCK — hard failure, pipeline must stop (git missing, invalid URL, MCP not configured)
• FAILURE — partial/ambiguous failure (git identity missing but git present)
• SUCCESS — all checks pass

Git not available:

{
  "status": "BLOCK",
  "errors": [{"code": "GIT_NOT_FOUND", "message": "Git not installed", "fix": "Install git"}]
}

Invalid URL:

{
  "status": "BLOCK",
  "errors": [{"code": "INVALID_URL_PATTERN", "message": "URL matches no supported pattern", "provided": "..."}]
}

CRITICAL: Return ONLY valid JSON. No markdown fences. No explanations. On catastrophic failure (cannot construct output): emit {"status":"BLOCK","errors":[{"code":"INTERNAL_ERROR","message":"<reason>"}]}.