Opening PRs Skill | Agent Skills

Opening PRs

A flowing graph that turns the imperative "create branch, push files, open a PR, poll mergeable_state" workflow into a structural DAG. The "NEVER push directly to main" rule is encoded as a validate= gate that physically can't be skipped.

from opening_prs import open_pr

result = open_pr(
    repo="owner/repo",
    branch_name="feat/cool-thing",
    title="Add cool thing",
    body="## Summary\n\n...",
    files=[
        ("src/cool.py", "<file content>"),
        ("docs/cool.md", "<file content>"),
    ],
    base="main",  # default; protected names are also rejected
)

print(result["pr_url"])             # https://github.com/.../pull/N
print(result["mergeable_state"])    # clean | dirty | unstable | behind | blocked

What this fixes

The gh pr create workflow (or hand-rolled API calls) has five steps in prose form:

Determine the branch name
Get the base branch's HEAD SHA
Create the branch
Push files to the branch
Create the PR
Poll mergeable_state until GitHub finishes computing it

Each step has known failure modes:

Step 1: Accidentally pushing to main — the diagnosed pattern that motivated github-procedures §6 in the first place.
Step 6: GitHub returns mergeable_state: null immediately after creation. Need to poll. "Wait a few seconds and check" is prose, not a procedure — so it gets skipped under context pressure.

This skill encodes both as flowing primitives:

determine_branch ──▶ guard ──▶ get_base_head ──▶ create_branch
                      │                              │
                      │                              ▼
                      │                        push_files
                      │                              │
                      │                              ▼
                      │                         create_pr
                      │                          /        \
                      │                         ▼          ▼
                      │                  wait_mergeable  present_pr [terminal]
                      │
                      └─ validate=must_not_be_base_branch

validate=must_not_be_base_branch rejects branch_name in {"main", "master", "trunk", "production", "prod"} — case-insensitive — and the configured base itself. The body of create_branch never fires for a protected name. No GitHub API call happens for an invalid branch name.
retry_until=lambda r: r["mergeable_state"] in SETTLED_STATES consumes the retry budget while GitHub computes the merge result. unknown and null keep polling; settled states (clean, dirty, unstable, behind, blocked) stop. Exhaustion is soft: the PR is still presented with the last observed state.

Auth

Requires GH_TOKEN (or GITHUB_TOKEN) in the environment. Classic PAT or fine-grained PAT with repo scope.

import os
os.environ["GH_TOKEN"] = "ghp_..."   # or load from a .env file

The skill sends User-Agent: opening-prs on every API call. (GitHub returns 401 "Bad credentials" without a UA, regardless of token validity. Common trap.)

Result shape

{
    "pr_url": "https://github.com/owner/repo/pull/N",
    "pr_number": 42,
    "pr_state": "open",
    "branch": "feat/cool-thing",
    "base": "main",
    "head_sha": "abc123...",
    "mergeable_state": "clean",
    "files_pushed": ["src/cool.py", "docs/cool.md"],
    "detached_failures": [],
}

Raises RuntimeError only if the main DAG fails (validate, branch creation, file push, or PR creation). Mergeable polling exhaustion is a soft failure — the PR exists, the field just isn't computed yet.

Tuning the mergeable poll

open_pr(
    ...,
    mergeable_poll_retries=8,         # default 8
    mergeable_poll_base_ms=2000,      # default 2s
    mergeable_poll_max_ms=8000,       # default 8s (cap on exponential backoff)
)

When NOT to use

Pushing many large files (the GitHub Contents API is one-file-per-PUT with base64 encoding — slow above ~10 files). Use git push if you have the CLI.
Needing to amend commits or rewrite history. This skill creates one commit per file via the contents API.
Anything involving force-push, branch deletion, or PR review-state manipulation. Out of scope; use a different tool.

Agent Skills: Opening PRs

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