compact-context

name	compact-context
description	Scan .copilot-tracking/ for stale or oversized tracking artifacts, produce compacted summaries, and archive originals. Use when tracking files accumulate beyond thresholds that degrade agent context quality.
argument-hint	[threshold-days=14] [max-files=40] [max-size-kb=500]

Compact Context

Reduce context noise by compacting old .copilot-tracking/ artifacts into dense summaries. Originals are archived, never deleted, preserving full audit history.

Agent-Intercom Communication (NON-NEGOTIABLE)

Call ping at session start. If agent-intercom is reachable, broadcast at every step. If unreachable, warn the user that operator visibility is degraded.

Event	Level	Message prefix
Session start	info	[COMPACT] Starting context compaction
Assessment complete	info	[COMPACT] Assessment: {file_count} files, {total_size_kb} KB across {dir_count} subdirectories
Stale batch identified	info	[COMPACT] Stale batch: {count} files in {subdirectory} older than {threshold} days
Files preserved	info	[COMPACT] Preserved {count} files referenced by active backlog tasks
Summary written	success	[COMPACT] Summary written: {file_path}
Archive complete	success	[COMPACT] Archived {count} originals to .copilot-tracking/archive/{subdirectory}/
Session complete	success	[COMPACT] Complete: {archived_count} files archived, {summary_count} summaries written
Nothing to compact	info	[COMPACT] Tracking directory healthy — no compaction needed

Subagent Depth Constraint

This skill is a leaf executor. It MUST NOT spawn additional subagents. Perform all work using direct tool calls.

Inputs

• ${input:threshold-days:14}: (Optional, defaults to 14) Files older than this threshold are candidates for compaction.
• ${input:max-files:40}: (Optional, defaults to 40) File count threshold that triggers compaction when exceeded.
• ${input:max-size-kb:500}: (Optional, defaults to 500) Total size threshold in KB that triggers compaction when exceeded.

Execution Steps

Phase 1: Assess

Scan .copilot-tracking/ to determine whether compaction is needed and identify stale artifacts.

1. Enumerate subdirectories: List all subdirectories in .copilot-tracking/ excluding archive/. Record the subdirectory name, file count, and total size for each.

2. Check thresholds: If the total file count (excluding archive/) is below ${input:max-files} AND total size is below ${input:max-size-kb} KB, broadcast [COMPACT] Tracking directory healthy and exit. No compaction needed.

3. Identify stale files: For each subdirectory, identify files with a last-modified date older than ${input:threshold-days} days from today. Group stale files by subdirectory.

4. Cross-reference active backlog items: Query backlogit for active or queued work items and scan their descriptions and implementation notes for file path references matching .copilot-tracking/ paths. Any tracking file referenced by an active backlog item is excluded from compaction regardless of age.

5. Build compaction manifest: For each subdirectory with stale files, record:

   • Subdirectory name
   • Files to compact (stale and not referenced by active tasks)
   • Files to preserve (recent or referenced by active tasks)
   • Total size of files to compact

6. Broadcast the assessment summary.

Phase 2: Compact

For each subdirectory batch in the compaction manifest:

1. Read stale files: Read each file in the batch. Extract key content:

   • Section headings (H2, H3 level)
   • Key decisions and their rationale
   • Outcomes and results (success/failure, commit hashes, task completions)
   • Error resolutions and workarounds
   • Discard verbose logs, raw command output, and intermediate debugging steps

2. Write summary file: Create a compacted summary at .copilot-tracking/{subdirectory}/{YYYY-MM-DD}-compacted-summary.md with this structure:

   ---
   type: compacted-summary
   date: YYYY-MM-DD
   source_count: {number of files compacted}
   source_date_range: "{oldest_date} to {newest_date}"
   ---
   
   # Compacted Summary: {subdirectory}
   
   Compacted from {source_count} files spanning {source_date_range}.
   
   ## Key Decisions
   
   * {decision} — {rationale} (from {source_file})
   
   ## Outcomes
   
   * {outcome description} (from {source_file})
   
   ## Error Resolutions
   
   * {error} — {resolution} (from {source_file})
   
   ## Preserved Context
   
   * {any critical context that would be lost without the originals}
   

3. Archive originals: Move the compacted files to .copilot-tracking/archive/{subdirectory}/. Create the archive subdirectory if it does not exist. Use file move operations, not copy-then-delete.

4. Broadcast: Report the summary file path and the count of archived originals.

5. Repeat for each subdirectory batch in the manifest.

Constraints

• Never delete files. All originals are moved to .copilot-tracking/archive/. The archive directory is the permanent home for compacted originals.
• Preserve active task references. Files referenced by active backlog tasks are never compacted, regardless of age or size.
• One summary per batch. Each subdirectory compaction produces exactly one summary file. Multiple compaction runs on the same subdirectory produce separate dated summaries.
• Idempotent. Running compaction twice on an already-compact directory produces no changes (threshold check exits early).