Contributing to pi

This skill exists to stop us sending half-baked upstream reports to Mario.

The maintainer standard is reasonable: understand the bug, isolate the boundary that actually breaks, and show a concrete repro. If we can't do that yet, we are still in local debugging mode — not upstream contribution mode.

When to Use

Use this skill when:

• working in ~/Code/badlogic/pi-mono
• filing or updating an issue on badlogic/pi-mono
• preparing a PR meant for upstream
• deciding whether a failure belongs in pi core, a provider adapter, an extension, or our local patches
• responding to maintainer questions like "which provider/model triggered this?" or "how is this possible?"

Read These First

Always read both files in the local clone before touching upstream threads:

• ~/Code/badlogic/pi-mono/CONTRIBUTING.md
• ~/Code/badlogic/pi-mono/AGENTS.md

The important bits:

• first-time contributors open an issue first and wait for maintainer approval (lgtm)
• issue and PR text must be concise and written in a human voice
• new issues should carry the right pkg:* labels
• after code changes run npm run check
• do not run the repo's blanket npm test
• if you need tests, run targeted tests from the relevant package root

For the repo/maintainer deep dive, read:

• references/pi-mono-research.md

Non-Negotiables

1. Reproduce on clean upstream before claiming a core bug

If the failure only happened in one of these environments, say that plainly and do more work before filing upstream:

• local repo build wired into ~/.local/bin/pi
• globally patched installs under ~/.bun/install/global/...
• sessions with custom extensions enabled
• branches with local instrumentation or emergency guards applied

Use a clean worktree when in doubt:

cd ~/Code/badlogic/pi-mono
git fetch origin
git worktree add /tmp/pi-mono-main origin/main
cd /tmp/pi-mono-main
npm install

If the bug disappears on clean origin/main, it is not yet an upstream core bug.

2. Identify the broken boundary, not just the crash site

"It crashed in packages/agent/src/agent-loop.ts" is not enough.

If a type-level invariant says the state is impossible, prove where reality violated the invariant:

• provider adapter emitted an invalid AssistantMessage
• extension mutated message state incorrectly
• local patch/build mismatch changed runtime behaviour
• external API returned something the adapter normalized badly

Upstream wants the cause chain, not just a defensive ?? [] around the symptom.

3. Capture provider/model and runtime conditions every time

For any LLM/runtime bug, record:

• provider
• model
• command path (pi, local repo build, published install)
• whether extensions were enabled
• relevant local patches
• commit SHA / branch

If you cannot answer "which provider/model triggered this?", you are not ready to open the issue.

4. Do not open a PR before the issue gets approval

CONTRIBUTING.md is explicit. New contributors start with an issue. A PR opened before approval is churn and will be closed.

5. Repeated AI slop after maintainer feedback can get you banned

Mario made this explicit on X on 2026-03-09 while linking issue #1993:

you will be banned from the pi-mono repo if:

1. you are a dick
2. you keep submitting clanker slop repeatedly for the same "issue" to which you got a reply and workaround from yours truely there is no way to appeal my decision.

Source: https://x.com/badlogicgames/status/2031085220221563021

Treat that as policy, not vibes.

If a maintainer already gave a workaround, explanation, or boundary call, do not re-litigate the same thing with a slightly reworded agent-generated issue. Either bring a new repro with stronger evidence, or shut up and go debug more.

Workflow

Step 1: confirm this belongs upstream

Ask, in order:

1. Does the failure reproduce on clean origin/main?
2. Does it reproduce with extensions disabled?
3. Does it reproduce with the published build, not just our repo-wired binary?
4. Can I point to the exact layer that produced the bad state?

If any answer is "no" or "not sure", keep digging locally.

Step 2: gather the evidence pack

Before filing an issue, collect this in a scratch note:

• one-sentence problem statement
• exact repro steps from repo root
• provider/model
• extension state (--no-extensions repro or not)
• clean vs patched build
• expected result
• actual result
• minimal log or message payload showing the bad state
• hypothesis for where the invariant broke
• package ownership (pkg:agent, pkg:ai, pkg:coding-agent, etc.)

For GitHub reading, use the maintainer-friendly command from AGENTS.md:

gh issue view <number> --json title,body,comments,labels,state

Read all comments before replying.

Step 3: reduce the repro

Strip it down until another person can run it without our whole machine state.

Good repros usually look like one of these:

• a small failing test in the affected package
• a fixture that produces the invalid normalized message
• a short command sequence from repo root
• an extension-disabled repro plus a separate note saying extensions make it worse

Bad repros look like:

• "during a longer session"
• "while chasing compaction"
• "somehow got a malformed message"
• "here's the guard I already wrote"

Step 4: write the issue like an adult

Keep it short. Human voice. No agent mush.

Use this shape:

Problem
- One sentence describing the failure.

Repro
1. Step one
2. Step two
3. Step three

Environment
- provider/model:
- build: clean origin/main | local repo build | published install
- extensions: on/off

Expected
- ...

Actual
- ...

Hypothesis
- The invariant appears to break in <provider|adapter|extension|core> because ...

Add the right pkg:* labels.

If you comment on an issue or PR, write the comment to a temp file first and preview it before posting.

Step 5: prepare the scoped fix

Prepare local repro, patch, and regression checks when requested. Maintainer approval gates opening an upstream PR under CONTRIBUTING.md; it does not block local preparation:

1. keep the patch minimal
2. add a failing regression test or fixture that proves the bug
3. run npm run check
4. run only the targeted tests needed by the touched package
5. avoid drive-by fixes or policy changes in the same patch

Lesson from pi-mono issue #1899

What we got wrong:

• we reported the crash site in packages/agent/src/agent-loop.ts
• we proposed a narrow guard immediately
• we did not include provider/model
• we did not provide concrete repro steps
• we did not explain whether the failure came from clean upstream, our repo-wired local pi build, our extensions, or our patched install
• we already had local evidence that this class of content.filter() crash also showed up in patched runtime paths around grind_stop, which pointed to a broader boundary problem than the issue body admitted

Mario's pushback was correct:

• on the type level, toolUse with missing content should be impossible
• without a repro, a guard patch looks like papering over an unknown lower-layer bug
• the likely fault domain is provider normalization or extension/runtime mutation until proven otherwise

Future rule:

If the maintainer can reasonably ask "how can this state even exist?", answer that before opening the issue.

Package Triage Heuristic

Use this to decide where a bug probably belongs:

• packages/ai — provider adapters, streaming normalization, tool-call event translation, malformed usage/stop reasons
• packages/agent — agent loop state machine, tool execution, context handling after normalized messages already exist
• packages/coding-agent — interactive mode, compaction UX, session persistence, slash commands, extension interaction surfaces
• local extensions / joelclaw runtime — if behaviour changes only with our extensions or patched local install

Don't dump provider or extension bugs into packages/agent because that is where the null dereference landed.

Pre-Submit Checklist

• Read CONTRIBUTING.md
• Read AGENTS.md
• Reproduced on clean origin/main
• Captured provider/model
• Captured extension state
• Captured build path (published vs local repo build)
• Identified likely broken boundary
• Wrote concise human issue body
• Added pkg:* labels
• Waited for maintainer approval before opening a PR

Don't Do This

• don't lead with the patch before the repro
• don't call something a core bug because a null dereference happened in core
• don't hide the fact that we run local patches or repo-wired binaries
• don't dump session-length narrative into the issue body
• don't use GitHub issues as a debugging notebook
• don't make Mario reverse-engineer our machine state