developer

Build a pr triager in YAML

An agent that labels new pull requests, assigns reviewers, and flags risky changes.

triggers.webhookwebbehavior

The pattern

A focused webhook agent that does not review code, only triages. It reads the diff at a high level, assigns labels (needs-review, breaking, docs-only), pings the right team, and posts a one-paragraph summary. Cheap, fast, and the cap on tool calls keeps it that way.

What good looks like

Labels and a summary within 60 seconds
Right team pinged based on which files changed
Risk tags are consistent across PRs
Costs under $0.01 per typical PR

Common pitfalls

Doing full review work in a triager, defeats the cost model
Inconsistent labels because the prompt is vague
No turn cap, freak PRs blow the budget
Pinging the wrong team during a refactor

The minimum YAML to ship this

app.yaml

1modules:2  web: {}34triggers:5  - id: pr-opened6    kind: webhook7    path: /hooks/pr-triage8    target: { agent: triager, message: "{{event.body.pull_request.title}}" }910behavior:11  rules:12    - condition: tool_calls > 813      action: gate1415agents:16  - id: triager17    modules: [{web: [fetch]}]18    brain: { model: claude-haiku-4-5 }19    system_prompt: "Read the diff at a high level. Tag risk. Be terse."

Ship in 5 minutes

Install Digitorn and deploy this agent

# 1. install runtime
curl -sSL https://digitorn.ai/install | sh

# 2. save the YAML above to ~/.digitorn/apps/my-pr-triager/app.yaml
mkdir -p ~/.digitorn/apps/my-pr-triager
# paste the YAML into app.yaml

# 3. deploy
digitorn deploy my-pr-triager

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Engineering notes from the Digitorn team. No marketing, no launch announcements, no "10 prompts that will change your life". Just the things we write that we'd want to read.

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The minimum YAML to ship this

app.yaml

1modules:2  web: {}34triggers:5  - id: pr-opened6    kind: webhook7    path: /hooks/pr-triage8    target: { agent: triager, message: "{{event.body.pull_request.title}}" }910behavior:11  rules:12    - condition: tool_calls > 813      action: gate1415agents:16  - id: triager17    modules: [{web: [fetch]}]18    brain: { model: claude-haiku-4-5 }19    system_prompt: "Read the diff at a high level. Tag risk. Be terse."

# 1. install runtime curl -sSL https://digitorn.ai/install | sh # 2. save the YAML above to ~/.digitorn/apps/my-pr-triager/app.yaml mkdir -p ~/.digitorn/apps/my-pr-triager # paste the YAML into app.yaml # 3. deploy digitorn deploy my-pr-triager