# Sessions

Pi saves conversations as sessions so you can continue work, branch from earlier turns, and revisit previous paths.

## Session Storage

Sessions auto-save to `~/.pi/agent/sessions/`, organized by working directory. Each session is a JSONL file with a tree structure.

```bash
pi -c                  # Continue most recent session
pi -r                  # Browse and select from past sessions
pi --no-session        # Ephemeral mode; do not save
pi --name "my task"    # Set session display name at startup
pi --session <path|id> # Use a specific session file or partial session ID
pi --fork <path|id>    # Fork a session file or partial session ID into a new session
```

Use `/session` in interactive mode to see the current session file, session ID, message count, tokens, and cost.

For the JSONL file format and SessionManager API, see [Session Format](session-format.md).

## Session Commands

| Command | Description |
|---------|-------------|
| `/resume` | Browse and select previous sessions |
| `/new` | Start a new session |
| `/name <name>` | Set the current session display name |
| `/session` | Show session info |
| `/tree` | Navigate the current session tree |
| `/fork` | Create a new session from a previous user message |
| `/clone` | Duplicate the current active branch into a new session |
| `/compact [prompt]` | Summarize older context; see [Compaction](compaction.md) |
| `/export [file]` | Export session to HTML |
| `/share` | Upload as private GitHub gist with shareable HTML link |

## Resuming and Deleting Sessions

`/resume` opens an interactive session picker for the current project. `pi -r` opens the same picker at startup.

If the selected session contains a blocked durable goal, Pi applies the same transition as
`/goal resume` before restarting that session's worker and process supervisors. `pi -c`, `pi -r`, and
`--session` use the same startup rule. Active goals remain active; completed or cancelled goals are
never reopened automatically.

Session replacement has an explicit recovery boundary. Preparation failure leaves the current runtime
untouched. If retiring the current runtime, rebinding, or starting supervision fails, Pi completes every
cleanup step, cleans the candidate, and reconstructs the previous session from its durable manager. A
failure in an extension's post-replacement `withSession` callback is reported separately because the
replacement is already valid and remains active. Process shutdown uses the same draining teardown and
waits for an already-admitted replacement before disposing the runtime it leaves active.

In the picker you can:

- search by typing
- toggle path display with Ctrl+P
- toggle sort mode with Ctrl+S
- filter to named sessions with Ctrl+N
- rename with Ctrl+R
- delete with Ctrl+D, then confirm

When available, pi uses the `trash` CLI for deletion instead of permanently removing files.

Use `/goal resume` when you want to resume the blocked goal in the current session without switching
sessions.

An explicit goal stated in normal chat does not require `/goal`. Phrases such as `Set a persistent
goal: ...`, `The goal is to ...`, `Keep working until this is complete: ...`, `this is a goal.
<task>`, a follow-up `this is a goal` / `the task is a goal` after a task, `instead of …, I want
to …`, or `I want to refactor/rewrite/rebuild/redesign …` create the same durable goal record.
Handover wording (`by the way`, `i'm handing over`, sub-agent or role assignment) is classification
only; the previous user task is the objective. Pi deliberately does not infer persistence from an
ordinary multi-step request, and it will not replace an unfinished goal implicitly. Active
chat-created goals use the normal automatic hidden continuation trigger and survive compaction
through one compact active-goal projection.

Reading a session `.jsonl` with `read` returns a labeled transcript (user/assistant/compaction or
branch summaries/tool names). Thinking, signatures, summary details, and successful tool payloads are
omitted.

## Naming Sessions

Use `/name <name>` to set a human-readable session name:

```text
/name Refactor auth module
```

Set the name at startup with `--name` or `-n`:

```bash
pi --name "Refactor auth module"
pi --name "CI audit" -p "Review this build failure"
```

Named sessions are easier to find in `/resume` and `pi -r`.

## Branching with `/tree`

Sessions are stored as trees. Every entry has an `id` and `parentId`, and the current position is the active leaf. `/tree` lets you jump to any previous point and continue from there without creating a new file.

<p align="center"><img src="images/tree-view.png" alt="Tree View" width="600"></p>

Example shape:

```text
├─ user: "Hello, can you help..."
│  └─ assistant: "Of course! I can..."
│     ├─ user: "Let's try approach A..."
│     │  └─ assistant: "For approach A..."
│     │     └─ user: "That worked..."  ← active
│     └─ user: "Actually, approach B..."
│        └─ assistant: "For approach B..."
```

### Tree Controls

| Key | Action |
|-----|--------|
| ↑/↓ | Navigate visible entries |
| ←/→ | Page up/down |
| Ctrl+←/Ctrl+→ or Alt+←/Alt+→ | Fold/unfold or jump between branch segments |
| Shift+L | Set or clear a label on the selected entry |
| Shift+T | Toggle label timestamps |
| Enter | Select entry |
| Escape/Ctrl+C | Cancel |
| Ctrl+O | Cycle filter mode |

Filter modes are: default, no-tools, user-only, labeled-only, and all. Configure the default with `treeFilterMode` in [Settings](settings.md).

### Selection Behavior

Selecting a user or custom message:

1. Moves the leaf to the selected message's parent.
2. Places the selected message text in the editor.
3. Lets you edit and resubmit, creating a new branch.

Selecting an assistant, tool, compaction, or other non-user entry:

1. Moves the leaf to that entry.
2. Leaves the editor empty.
3. Lets you continue from that point.

Selecting the root user message resets the leaf to an empty conversation and places the original prompt in the editor.

## `/tree`, `/fork`, and `/clone`

| Feature | `/tree` | `/fork` | `/clone` |
|---------|---------|---------|----------|
| Output | Same session file | New session file | New session file |
| View | Full tree | User-message selector | Current active branch |
| Typical use | Explore alternatives in place | Start a new session from an earlier prompt | Duplicate current work before continuing |
| Summary | Optional branch summary | None | None |

Use `/tree` when you want to keep alternatives together. Use `/fork` or `/clone` when you want a separate session file.

## Branch Summaries

When `/tree` switches away from one branch to another, pi can summarize the abandoned branch and attach that summary at the new position. This preserves important context from the path you left without replaying the whole branch.

When prompted, choose one of:

1. no summary
2. summarize with the default prompt
3. summarize with custom focus instructions

See [Compaction](compaction.md) for branch summarization internals and extension hooks.

## Session Format

Session files are JSONL and contain message entries, model changes, thinking-level changes, labels, compactions, branch summaries, and extension entries.

For parsers, extensions, SDK usage, and the full SessionManager API, see [Session Format](session-format.md).