Context and snapshots¶
Colossus saves the full conversation in a durable session. For each model turn, it prepares a bounded view of that history. A context snapshot summarizes older messages when the working view gets large; it does not remove the original messages.
Check the current context¶
In the Terminal UI, enter:
A status display looks like this. Your model, session ID, and numbers will differ:
◆ Context
Session 0195b640-8a41-7b35-948d-3d58b39e783a
Model profile codex
Messages 8
Tokens 614 / 344000
Context window 400000
Output reserve 16000
Safety reserve 40000
Compacted no
Snapshot —
| Field | What it means |
|---|---|
| Session | The conversation whose context is being measured. |
| Model profile | The profile selected for the primary model role. |
| Messages | Saved session messages; compaction does not delete them. |
| Tokens | Estimated current prepared context, followed by the effective input budget. This is not a usage or billing counter; the next prompt and tools can change the request size. |
| Context window | The configured total token window for the model profile. |
| Output reserve | Tokens held back for the model's response. |
| Safety reserve | Extra room kept for estimation differences and request overhead. |
| Compacted / Snapshot | Whether an active snapshot is shaping future context, and its ID when one is active. |
In this example, 400000 − 16000 − 40000 = 344000 tokens remain for input.
The estimated 614 tokens are well below that budget, so there is no reason to
compact this session now. The status is an estimate of the current context, not
a promise that every future prompt will fit.
From a shell, use the session ID in the same workspace and configuration:
When Colossus compacts a session¶
With automatic compaction enabled, Colossus creates a snapshot when the working context crosses the configured threshold. The default threshold is 85% of the effective input budget. A snapshot keeps a bounded summary of older messages and preserves recent messages for the next model turn. The full transcript remains in the session; Sessions shows how to read it.
After compaction, /context status reports Compacted: yes and a Snapshot
ID. The token estimate may fall because the model receives the summary in place
of the older message range. If a single new turn or required context is too large,
compaction can still fail rather than silently discard it.
Operators can adjust the threshold and preservation settings in context configuration.
Inspect or restore snapshots¶
Use these commands in the Terminal UI:
| What you want to do | Command |
|---|---|
| List saved snapshots for this session | /context list |
| Create a snapshot now | /context compact |
| Use an older snapshot for future turns | /context restore SNAPSHOT_ID |
Manual compaction changes the model's working view even when the automatic threshold has not been reached. Restore changes which immutable snapshot is active; it does not delete later messages or rewrite the snapshot. Both actions follow the configured authorization rules.
From a shell, use the matching commands with the session ID:
colossus -w /absolute/path/to/repository context list SESSION_ID
colossus -w /absolute/path/to/repository context compact SESSION_ID
colossus -w /absolute/path/to/repository context restore SESSION_ID SNAPSHOT_ID
Colossus Desktop also lists the same snapshots in a thread's Snapshots view. For context that should be reusable across conversations, use Memories instead of relying on a session snapshot.
What's next?¶
-
Sessions
Read the complete transcript or return to the conversation later.
-
Memories
Save useful context that can be found beyond this one session.