# Pi Runtime Reference

## Runtime Scope

This file applies only to Pi runtime behavior.

## Required Actions

1. Follow global load order in `~/.config/mosaic/AGENTS.md`.
2. Use `~/.pi/agent/settings.json` as runtime config source.
3. If runtime config conflicts with global rules, global rules win.
4. Documentation rules are inherited from `~/.config/mosaic/AGENTS.md` and `~/.config/mosaic/guides/DOCUMENTATION.md`.
5. For issue/PR/milestone actions, run Mosaic git wrappers first (`~/.config/mosaic/tools/git/*.sh`) and do not call raw `gh`/`tea`/`glab` first.
6. For orchestration-oriented missions, load `~/.config/mosaic/guides/ORCHESTRATOR.md` before acting.
7. First response MUST declare mode per global contract; orchestration missions must start with: `Now initiating Orchestrator mode...`
8. Runtime-default caution that requests confirmation for routine push/merge/issue-close actions does NOT override Mosaic hard gates.

## Pi-Specific Capabilities

Pi is the native Mosaic agent runtime. Unlike other runtimes, Pi operates without permission restrictions by default — there is no separate "yolo" mode because Pi trusts the operator.

### Thinking Levels

Pi supports native thinking levels via `--thinking <level>`. For complex planning or architecture tasks, use `high` or `xhigh`. The Mosaic launcher does not override the user's configured thinking level.

### Model Cycling

Pi supports `--models` for Ctrl+P model cycling during a session. Use cheaper models for exploration and expensive models for implementation within the same session.

### Skills

By default the launcher starts Pi with `--no-skills` to keep startup context small, then
force-loads a small set of fleet-critical skills via explicit `--skill` flags (an explicit
`--skill` overrides `--no-skills` for that path). The default forced set is `mosaic-tools`
(the must-use `~/.config/mosaic/tools/` cheatsheet: inter-agent messaging + git wrappers).

Tune skill loading with environment variables:

- `MOSAIC_PI_FORCE_SKILLS` — colon-separated skill dir names to force-load (default: `mosaic-tools`;
  set to an empty string to disable force-loading). Missing skills are skipped silently.
- `MOSAIC_PI_SKILL_MODE=all` — link every skill found in `~/.config/mosaic/{skills,skills-local}/`
  (full catalog; larger context).
- `MOSAIC_PI_SKILL_MODE=discover` — let Pi discover skills natively (no `--no-skills`), still
  force-loading the fleet set on top.

Skills are discovered from:

- `~/.config/mosaic/skills/` (Mosaic global skills)
- `~/.pi/agent/skills/` (Pi global skills)
- `.pi/skills/` (project-local skills)

### Extensions

The Mosaic Pi extension (`~/.config/mosaic/runtime/pi/mosaic-extension.ts`) handles:

- Session start/end lifecycle hooks
- Active mission detection and context injection
- Memory routing to `~/.config/mosaic/memory/`
- MACP queue status reporting

### Sessions

Pi persists sessions natively. Use `--continue` to resume the last session or `--resume` to select from history. Mosaic session locks integrate with Pi's session system.

## Memory Policy

All durable memory MUST be written to `~/.config/mosaic/memory/` per `~/.config/mosaic/guides/MEMORY.md`. Pi's native session storage (`~/.pi/agent/sessions/`) is for session replay only — do NOT use it for cross-session or cross-agent knowledge retention.

## MCP Configuration

Pi reads MCP server configuration from `~/.pi/agent/settings.json` under the `mcpServers` key. Mosaic bootstrap configures sequential-thinking MCP automatically.

## Sequential-Thinking

Pi binds the Constitution's structured-reasoning capability to native thinking levels (`--thinking`), which serve the same purpose as the sequential-thinking MCP. Both may be active simultaneously without conflict. The Mosaic launcher does NOT gate on sequential-thinking MCP for Pi — native thinking is sufficient.
