Ski Memory Manager

Description

Reusable skill that provides operations to manage the memory/ directory of a project. Memory files are condensed summaries (~1-2KB) that allow a workflow orchestrator to quickly orient itself when resuming work on an existing project, without consuming the tokens required by a full context ledger.

The memory file is a quick-start summary; the context ledger is the full record.

Input / Output

Input (common): memory_dir, project_name — varies by operation (see below).

Output: Created or updated memory file (for save) or a memory content block ready for injection (for load-last).

Operations

save — Write or update a session memory file

Creates or updates a condensed memory file for the current session. If a file with the same session timestamp already exists, it overwrites it. Otherwise, creates a new file.

Input:

Output: File {memory_dir}/{session_timestamp}-{project_name}.md created with structure:

---
schema_version: 1.1
project-name: {project_name}
session: {session_timestamp}
mode: {mode}
status: {status}
last-checkpoint: {last_checkpoint}
checkpoints-approved: [{checkpoints_approved}]
checkpoint_decisions:
  CP-S0: { option: A, note: "Approved as-is" }
  CP-S1: { option: B, note: "Adjusted: added 2 triggers" }
  CP-S2: { option: C, regenerated_count: 1 }
target-dir: {target_dir}
last_session_at: 2026-04-25T10:00:00Z
---

## Session summary
{session_summary}

## Steps completed
- S0: {steps_completed.S0}
- S1: {steps_completed.S1}
...

## Active state
{active_state}

## Key decisions
- {key_decisions[0]}
- {key_decisions[1]}
...

Schema version note (v3 — 4.2.1): The schema_version field distinguishes v3 Memory snapshots (1.1) from v2 baseline (absent or 1.0). When load-last reads a file without schema_version, treat it as v1.0 and silently migrate fields on the next save (back-compat).

Status semantics:

When: After each checkpoint approval and at session close.

load-last — Load the most recent memory for a project

Scans the memory directory for files matching the project name and returns the most recent one.

Input:

Logic:

1. List all files in {memory_dir}/.
2. Filter files whose name ends with -{project_name}.md.
3. Sort by timestamp prefix (descending) — the filename format YYYY-MM-DD-HH-MM- guarantees lexicographic = chronological order.
4. Read the content of the first (most recent) match.
5. Compute time-since-last-session: read last_session_at from the loaded Memory; compute time_since_last_session_hours = now - last_session_at. Surface as part of the load output:
   • "Resuming foo-system (last touched 3 days ago, status: in-progress at CP-S2)".
6. Return the content of the most recent memory file.

Output: Full content of the most recent memory file, or empty with message "No previous memory found for project '{project_name}'". When v3 verification triggers, also include a one-line summary of the resolution.

When: At workflow startup, before initializing a new session, to check for existing project context.

Procedure

Use operations in this order per workflow run:

1. load-last — at workflow start, check for existing context
2. save — after each checkpoint approval (update in-progress state)
3. save — at workflow close (final state with status=completed)

Usage notes

• The workflow is responsible for composing the memory content. This skill only handles the file mechanics.
• Memory files are designed to be small (~1-2KB). Do NOT dump the full context ledger into memory — use concise summaries.
• If memory_dir does not exist, emit an error and notify the workflow.
• Memory files are never deleted — they accumulate as a historical record of sessions.
• Multiple sessions for the same project are expected (different timestamps).

Error Handling

• save called with missing memory_dir: Emit error "memory directory not found at {memory_dir}" and halt.
• load-last finds no matching files: Return empty with informational message (not an error — new projects won't have memory).
• Corrupted or unreadable file: Skip it and try the next most recent. If all fail, return empty with warning.