dependabot-config

name

dependabot-config

description

Generate or update Dependabot configuration files for projects. Use this skill whenever the user asks to add, create, update, configure, or fix Dependabot for a project — including phrases like "set up Dependabot", "add Dependabot config", "update my dependabot.yml", "enable Dependabot updates", or "configure automated dependency updates". Always apply this skill even if the user only mentions one ecosystem (e.g. "add Dependabot for npm") — the canonical config covers all required ecosystems.

Dependabot Configuration Skill

Produces the canonical .github/dependabot.yml configuration for any project. Always emit the complete canonical config, never a partial one, unless the user explicitly overrides a specific field after reviewing it.

---

Canonical Configuration

The authoritative configuration to emit is:

version: 2
updates:
  - package-ecosystem: "npm"
    directory: "/"
    schedule:
      interval: "daily"
    cooldown:
      default-days: 7
      semver-major-days: 7
      semver-minor-days: 3
      semver-patch-days: 2
      include:
        - "*"

  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "daily"
    cooldown:
      default-days: 7
      include:
        - "*"

---

Cooldown Rationale

Document this to the user when relevant:

Field	Value	Reasoning
default-days	7	Catch-all safety buffer for uncategorised updates
semver-major-days	7	Breaking changes warrant the longest review window
semver-minor-days	3	New features; moderate confidence, shorter delay
semver-patch-days	2	Bug/security fixes; high confidence, fast-track
include: ["*"]	—	Apply cooldown rules to all packages without exception

---

Workflow

1. Identify context

• Determine whether a .github/dependabot.yml already exists in the project.
  • Exists: read the file, explain any differences from the canonical config, then overwrite it with the canonical config using a file tool.
  • Does not exist: create .github/dependabot.yml with the canonical config using a file tool.

2. Check for non-npm ecosystems

If the project uses additional package ecosystems (e.g. pip, cargo, bundler, docker, composer), add an additional updates block per ecosystem using the same schedule and cooldown values. Keep npm and github-actions blocks unchanged. Use the references file for additional ecosystem identifiers if needed.

3. Handle directory variations

If the user's project has packages in subdirectories (e.g. a monorepo), ask which directories need coverage and emit one block per directory per ecosystem, keeping all other fields from the canonical config intact.

4. Write the file

Write the config directly to .github/dependabot.yml in the project root using a file tool — do not present it as a fenced code block for the user to copy manually. Ensure the .github/ directory exists before writing.

After writing, confirm the file path to the user and follow with a concise explanation of what was configured and why — particularly the cooldown strategy — without repeating every field verbatim.

---

Constraints

• Never omit the cooldown block from any ecosystem entry.
• semver-* cooldown fields are only valid for package managers that use semver (e.g. npm, pip, cargo). Do not include semver-major-days, semver-minor-days, or semver-patch-days for github-actions or any other non-semver ecosystem — Dependabot will reject the config.
• Never change the canonical values unless the user explicitly requests it and provides a reason (e.g. a monorepo with a stricter release cadence).
• Always include github-actions as an ecosystem, even if the user only asked about npm or another runtime ecosystem.
• YAML formatting: two-space indentation, string values quoted, list items with - prefix. Validate indentation before emitting — malformed YAML is a silent failure in Dependabot.

---

Reference

See references/ecosystems.md for the full list of Dependabot-supported package-ecosystem identifiers and their directory conventions.