pr-context-packer

name: pr-context-packer description: Build PR-focused context packs (PR description + git diff + full changed files + related files via Scribe), then budget-fit and token-check with o200k-base.

PR Context Packer

Use this skill when the user wants high-signal PR context for an LLM:

• include GitHub PR title/body by default,
• include the actual diff,
• include full current code for changed files,
• optionally expand with related files discovered via Scribe,
• fit related files into the remaining token budget,
• verify final fit against a context window budget.

What it does

prepare-pr-context.sh:

1. Resolves PR base (--base or auto-detect)
2. Pulls GitHub PR title/body by default (via gh, with graceful fallback)
3. Captures changed files + full git diff (base...HEAD)
4. Includes full current content of changed files (safe filters applied)
5. Optionally expands related files using Scribe covering-set (dependents included by default)
6. Ranks related candidates and greedily fits them into remaining token budget
7. Writes a single final text file plus manifests (changed/related/omitted + related-omitted + selection + scribe-target audit)
8. Counts tokens with tokencount --encoding o200k-base and trims low-priority related files if needed

Command

$HOME/dev/pi-skills/pr-context-packer/prepare-pr-context.sh <project_dir> [options]

Common invocations

# Typical PR pack (tmp output by default)
$HOME/dev/pi-skills/pr-context-packer/prepare-pr-context.sh ~/dev/mobile-1 --base origin/main

# Disable Scribe expansion (diff + changed files only)
$HOME/dev/pi-skills/pr-context-packer/prepare-pr-context.sh ~/dev/mobile-1 --base origin/main --no-scribe

# Keep output in repo prompt/ instead of /tmp
$HOME/dev/pi-skills/pr-context-packer/prepare-pr-context.sh ~/dev/mobile-1 --base origin/main --in-project-output

# Tight budget + fail if over
$HOME/dev/pi-skills/pr-context-packer/prepare-pr-context.sh ~/dev/mobile-1 --base origin/main --budget 180000 --fail-over-budget

Key options

• --base <ref> base ref to diff against (default: auto-detect)
• --pr <ref> explicit PR number/url/branch for gh pr view lookup
• --no-pr-description skip GitHub PR title/body section
• --tmp-output write output to /tmp/context-packer/... (default)
• --in-project-output write output to <repo>/prompt/
• --no-scribe disable Scribe related-file expansion
• --no-dependents disable dependent-file expansion (dependents are included by default)
• --scribe-max-depth <n> and --scribe-max-files <n> control each covering-set query
• --scribe-target-limit <n> cap number of changed files used as Scribe targets (default: 0 = all)
• --max-related <n> cap ranked related candidate pool before budget fitting (0 disables related section)
• --budget <tokens> token budget (default: 272000)
• --fail-over-budget return non-zero when over budget
• --include-lockfiles, --include-env, --include-secrets for explicit opt-ins

Output manifests

For <output>.txt, the script writes:

• <output>.changed.files.txt
• <output>.related.files.txt
• <output>.omitted.files.txt (changed files omitted by safety filters)
• <output>.related.omitted.files.txt (related candidates omitted with reasons)
• <output>.related.selection.tsv (per-related candidate decision + token estimate)
• <output>.scribe.targets.tsv (per-target Scribe status + possible max-files cap signals)

Requirements

• tokencount (cargo install tokencount)
• Optional GitHub CLI (gh) for auto PR title/body inclusion
• Optional Scribe for related-file expansion:
  • npm i -g @sibyllinesoft/scribe, or
  • cargo install scribe-cli, or
  • npx @sibyllinesoft/scribe available
• Optional clipboard tools:
  • macOS: pbcopy
  • Linux Wayland: wl-copy