compact-session

name	compact-session
description	Use when asked to manually compact a session's memory, trigger session summarization, or reduce a long session's context footprint.
disable-model-invocation	true
allowed-tools	["Bash(ll-compact-session:*)","Read"]
metadata	{"short-description":"Use when asked to manually compact a session's memory or trigger session summ"}

Compact Session Skill

Manually triggers session-memory compaction for one session — the same LCM compaction path (session_store.compact_session) that fires automatically in the background once a session crosses the soft token threshold (FEAT-2598). Produces leaf/condensed summary_nodes rows and prints the resulting CompactResult (summary text, covered message count, token estimate).

This is the LCM/semantic-summarization axis — distinct from ll-session compact, which sweeps the separate retention axis (kind='retention' raw_events summarization, ENH-1906/ENH-2581). Do not confuse the two.

When to Activate

Proactively offer or invoke this skill when the user:

• Asks to compact, summarize, or condense a session manually
• Wants to reduce a long-running session's context footprint before continuing
• Asks whether a session has been compacted yet, or wants to see its summary
• Mentions the session is approaching a context limit and wants to trigger summarization early rather than waiting for the automatic soft-threshold trigger

Arguments

$ARGUMENTS

• session_id (required) — the session to compact. If the user doesn't name one, use the current session's ID (available from the host CLI's session context) or ask which session they mean.
• --db PATH (optional) — session database path (default: .ll/history.db)
• --json (optional) — machine-readable output

How to Use

Run the ll-compact-session CLI command:

ll-compact-session SESSION_ID

For programmatic access (e.g. from another skill or loop evaluator):

ll-compact-session SESSION_ID --json

The JSON payload includes new_leaves (leaf nodes created this run), summary_text (the condensed summary, null if the session has fewer than two leaf blocks), compacted_messages (covered message_events ids), and context_token_estimate.

Compaction is idempotent — repeated calls do not create duplicate nodes. Note that history.compaction.enabled (default false in .ll/ll-config.json) gates whether an LLM summary is produced at all; when disabled, ll-compact-session still runs but the leaf/condensed summaries fall back to deterministic truncation (no LLM cost) per the existing LCM three-level escalation in session_store._summarize_block.

Examples

User says	Action
"Compact this session before we keep going"	ll-compact-session <current-session-id>
"Has session abc123 been summarized?"	ll-compact-session abc123 --json, report summary_text
"This loop's session is getting huge, trigger compaction now"	ll-compact-session <session-id>