> ## Documentation Index
> Fetch the complete documentation index at: https://docs.51ultron.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Session Management

> Persisted transcripts, resumable sessions, automatic compression, and cost tracking.

Every Ultron session is persisted. Transcripts are saved turn-by-turn as JSONL. Sessions can be resumed exactly where they left off.

## Context injection at session start

Before you type your first message, Ultron loads context in a specific order:

```text theme={null}
Session start — context assembly
├── 1. Static system instructions    — Ultron behavior rules, tool use guidelines, quality gates
├── 2. User profile                  — business name, ICP, voice tone, competitors, platforms
├── 3. Connected integrations         — list of active services (Gmail, Stripe, HubSpot, etc.)
├── 4. Relevant memories              — max 5 entries selected by Sonnet-powered recall
└── 5. Current date                  — injected as system reminder
```

This order is intentional. Static content at the top enables cache sharing across sessions (lower latency, lower cost). Dynamic content at the bottom gets fresh context every time.

## Session persistence

* Transcripts saved as **JSONL** — one JSON object per message turn
* Includes: message content, tool calls, tool results, token counts, timestamps
* Resume at any time — context is fully reconstructed from the transcript
* Cost tracking accumulated per session and per-turn

## Automatic compression

As conversations grow, the compression engine manages context automatically. You never need to manually summarize or restart a session:

1. **MicroCompact** fires first — removes stale tool outputs from old turns (no API call)
2. **Session Memory Compact** — uses stored memories as compression baseline (no API call)
3. **API Digest** — full LLM summary via fast model (last resort)

After each compression, a boundary marker is inserted. All subsequent processing only touches messages after that boundary, preventing repeated compression of already-compressed content.

## Cost tracking

| What's tracked         | Where to see it  |
| ---------------------- | ---------------- |
| Input tokens per turn  | Settings → Usage |
| Output tokens per turn | Settings → Usage |
| Model used per call    | Settings → Usage |
| Total session cost     | Settings → Usage |

<Tip>
  Long research sessions with many tool calls accumulate tokens quickly. Check usage after complex sessions to calibrate which tasks to run in API mode vs sandbox mode.
</Tip>