GitHub Agentic Workflows 实现跨仓库文档自动化

“Where are the docs?” It’s a question nobody on a product team enjoys answering. The honest reply is usually some variant of “behind.” A writer is staring at a closed pull request, trying to reverse-engineer what changed. The pull request’s author has already moved on. By the time the doc actually publishes, the feature has shipped, sometimes more than once.

That used to be us on the Aspire team (we’re a small team of 10 building dev tools for distributed apps). A few months back, we were trying to figure out how to safely bring AI into automations we already trusted. That’s when we discovered GitHub Agentic Workflows. I started bolting prototypes into microsoft/aspire.

Here’s what that bought us, in numbers pulled straight out of GitHub: for Aspire 13.3 and 13.4, 82 feature-docs pull requests merged at a median of 44.8 hours after the product pull request, every one of them reviewed by the engineer who shipped the feature. No new headcount. No process retraining. Just a different way of asking “who writes this?”

🔒 The constraint: cross-repo automation is the hard part

Our product lives in microsoft/aspire and our docs site lives in microsoft/aspire.dev—different repo, deploy target, and review chain. Most teams figure out same-repo automation pretty quickly; cross-repo automation is where things get sharp. Broad repo-scoped tokens belong in a museum, and any responsible security posture (ours included) restricts them accordingly. That’s a good thing. It’s also a real bottleneck if the place where you write the docs isn’t the place where you write the code.

The default workflow for years was:

• Engineer ships a feature in microsoft/aspire.
• Docs writer notices weeks later.
• Docs writer opens the pull request, reads the diff, and pings the engineer to clarify what changed.
• Engineer is on the next feature, vaguely remembers, replies with half the picture.
• Docs draft ships, sometimes against a release that’s already out.

This is the reverse-engineering tax. We needed automation that crossed repos without handing an agent a write-everywhere token. GitHub Agentic Workflows turned out to be the answer.

🤖 Why GitHub Agentic Workflows

GitHub Agentic Workflows is a project from the GitHub Next team that I keep describing to people as “GitHub Actions, but with a model as the work-item processor and guard rails that satisfy security review.” That’s reductive, but it’s close.

The shape of it:

• You author a workflow as a single markdown file (.github/workflows/my-thing.md). YAML-style frontmatter on top, an English-language prompt underneath.
• You run GitHub Agentic Workflows compile, and it generates a sibling .lock.yml (a normal GitHub Actions workflow) that you commit alongside.
• At runtime, the workflow runs an agent against your prompt with a constrained toolset.
• Critically, the agent doesn’t write to GitHub directly. It emits intent (a JSON blob describing the pull requests, issues, and comments it wants to create), and a separate, narrowly scoped job (the safe-outputs handler) materializes that intent against a per-workflow GitHub app.

That last bullet is the unlock. The agent gets read access and a prompt. Writes go through a tiny verifiable pipeline with explicit allow-lists. Security review nods. We ship.

💚 A small aside: kindred stacks

I love when the tools you’re using to build are built with the same tools you’re using to build with. The GitHub Agentic Workflows docs are built with Astro and Starlight. So is aspire.dev—Astro with Starlight, dressed up with the wider Starlight plugin ecosystem (astro-mermaid, starlight-llms-txt, starlight-sidebar-topics, starlight-image-zoom, the gorgeous @catppuccin/starlight theme, and more. Shout-out to Chris Swithinbank and the Starlight maintainers, the entire ecosystem feels designed by people who genuinely care).

There’s a real kinship there. The tool we use to automate docs and the docs site we automate into share the same foundation. Convenient, because the Mermaid sequence diagram in the next section renders the exact same way in both worlds.

The end-to-end pipeline

Here’s the flow we landed on. The protagonist is a workflow called pr-docs-check.md living in microsoft/aspire.

A run starts on pull_request: closed against main or release/*, gated by merged == true. From there, the workflow first runs a deterministic target branch resolver in plain bash before the agent ever wakes up:

• Pull request milestone title (e.g. 13.4 → release/13.4 on aspire.dev).
• Linked-issue milestone title (parse Fixes/Closes/Resolves #N from the body, fetch each issue, take the first non-empty milestone).
• Pull request base ref, if it matches release/X.Y[.Z].
• Fall back to main.

This is the linchpin. Milestones in the product repo map cleanly to release branches in the docs repo. When the agent finally runs, it knows exactly where the docs should land without any creative writing about target branches or guessing.

The agent reads the diff, scans linked issues, and decides: does this need docs? If yes, it drafts the actual content in a checked-out microsoft/aspire.dev workspace, following our existing doc-writer skill (voice, MDX conventions, Starlight components). It then emits a create_pull_request safe-output and hands off.

The safe-outputs handler takes over:

• Title prefix: [docs]
• Label: docs-from-code
• draft: true (we never auto-merge)
• Base branch: agent-supplied, restricted to main or release/*
• Target repo: microsoft/aspire.dev
• Reviewer: the SME identified from the source pull request’s reviews—i.e., whoever the product team trusted to approve the feature, now gets asked to approve the doc for that feature.

A companion job posts a marker comment back on the source pull request with the docs pull request link and minimizes any older pr-docs-check comments on re-run. The engineer who just hit Merge gets a notification within a few minutes: “Here’s the docs draft. Look it over?”

🔐 The safe-outputs contract

The whole security story comes down to a small, boring stretch of frontmatter:

tools: github: toolsets: [repos, issues, pull_requests] min-integrity: approved # only run pinned, integrity-checked actions allowed-repos: - microsoft/* github-app: app-id: ${{ secrets.ASPIRE_BOT_APP_ID }} private-key: ${{ secrets.ASPIRE_BOT_PRIVATE_KEY }} owner: "microsoft" repositories: ["aspire.dev", "aspire"] safe-outputs: create-pull-request: title-prefix: "[docs] " labels: [docs-from-code] draft: true # human-in-the-loop, always base-branch: main allowed-base-branches: [main, release/*] target-repo: "microsoft/aspire.dev" protected-files: blocked # AGENTS.md, manifests, security config: hands off fallback-as-issue: true

That’s the deal in plain text. The agent gets a GitHub App token whose installation is scoped to exactly two repositories—the product repo and the docs repo—and nothing else in the org is reachable. It can only land pull requests against main or release/*. AGENTS.md and dependency manifests are off-limits by policy. If the pull request creation fails (network blip, conflict, anything), the framework falls back to filing an issue, so nothing is silently dropped.

This is the part security review actually liked. The agent’s reasoning is fuzzy. The action surface is not.

📊 By the numbers

Here are the stats from a rolling 30-day window (May 3 – June 2, 2026) spanning the back end of the Aspire 13.3 release and the run-up to 13.4: