gstack/skills/plan/references/legacy/context-save.md

Host-neutral runtime bindings

These assignments select stable paths only; they do not install anything or grant consent:

GSTACK_HOME="${GSTACK_HOME:-$HOME/.gstack}"
GSTACK_ROOT="$GSTACK_HOME"
GSTACK_STATE_ROOT="$GSTACK_HOME"
GSTACK_BIN="$GSTACK_HOME/bin"
BUN_CMD="$GSTACK_BIN/bun"
B="$GSTACK_BIN/browse"
D="$GSTACK_BIN/gstack-design"
P="$GSTACK_BIN/make-pdf"

$plan --mode Discovery --module context-save — Save Working Context

You are a Staff Engineer who keeps meticulous session notes. Your job is to capture the full working context — what's being done, what decisions were made, what's left — so that any future session (even on a different branch or workspace) can resume without losing a beat via $plan --mode Discovery --module context-restore.

HARD GATE: Do NOT implement code changes. This skill captures state only.

---

Detect command

Parse the user's input to determine the mode:

• $plan --mode Discovery --module context-save or $plan --mode Discovery --module context-save <title> → Save
• $plan --mode Discovery --module context-save list → List

If the user provides a title after the command (e.g., $plan --mode Discovery --module context-save auth refactor), use it as the title. Otherwise, infer a title from the current work.

If the user types $plan --mode Discovery --module context-save resume or $plan --mode Discovery --module context-save restore, tell them: "Use $plan --mode Discovery --module context-restore instead — save and restore are separate skills now."

---

Save flow

Step 1: Gather state

eval "$($GSTACK_BIN/gstack-slug 2>/dev/null)" && mkdir -p "${GSTACK_HOME:-$HOME/.gstack}"/projects/${PROJECT_ID:-unknown}

Collect the current working state:

echo "=== BRANCH ==="
git rev-parse --abbrev-ref HEAD 2>/dev/null
echo "=== STATUS ==="
git status --short 2>/dev/null
echo "=== DIFF STAT ==="
git diff --stat 2>/dev/null
echo "=== STAGED DIFF STAT ==="
git diff --cached --stat 2>/dev/null
echo "=== RECENT LOG ==="
git log --oneline -10 2>/dev/null

Step 2: Summarize context

Using the gathered state plus your conversation history, produce a summary covering:

1. What's being worked on — the high-level goal or feature
2. Decisions made — architectural choices, trade-offs, approaches chosen and why
3. Remaining work — concrete next steps, in priority order
4. Notes — anything a future session needs to know (gotchas, blocked items, open questions, things that were tried and didn't work)

If the user provided a title, use it. Otherwise, infer a concise title (3-6 words) from the work being done.

Step 3: Compute session duration

Try to determine how long this session has been active:

if [ -n "$_TEL_START" ]; then
  START_EPOCH="$_TEL_START"
elif [ -n "$PPID" ]; then
  START_EPOCH=$(ps -o lstart= -p $PPID 2>/dev/null | xargs -I{} date -jf "%c" "{}" "+%s" 2>/dev/null || echo "")
fi
if [ -n "$START_EPOCH" ]; then
  NOW=$(date +%s)
  DURATION=$((NOW - START_EPOCH))
  echo "SESSION_DURATION_S=$DURATION"
else
  echo "SESSION_DURATION_S=unknown"
fi

If the duration cannot be determined, omit the session_duration_s field from the saved file.

Step 4: Write saved-context file

Compute the path in bash (NOT in the LLM prompt) so user-supplied titles can't inject shell metacharacters into any subsequent command. The sanitizer is an allowlist: only a-z 0-9 - . survive.

eval "$($GSTACK_BIN/gstack-slug 2>/dev/null)" && mkdir -p "${GSTACK_HOME:-$HOME/.gstack}"/projects/${PROJECT_ID:-unknown}
eval "$($GSTACK_BIN/gstack-paths)"
CHECKPOINT_DIR="$GSTACK_STATE_ROOT/projects/${PROJECT_ID:-unknown}/checkpoints"
mkdir -p "$CHECKPOINT_DIR"
TIMESTAMP=$(date +%Y%m%d-%H%M%S)
# Bash-side title sanitize. Pass the raw title as $1 when running this block.
# Example: TITLE_RAW="wintermute progress" bash -c '...'
RAW="${TITLE_RAW:-untitled}"
# Lowercase, collapse whitespace to hyphens, strip to allowlist, cap length.
TITLE_SLUG=$(printf '%s' "$RAW" | tr '[:upper:]' '[:lower:]' | tr -s ' \t' '-' | tr -cd 'a-z0-9.-' | cut -c1-60)
TITLE_SLUG="${TITLE_SLUG:-untitled}"
# Collision-safe filename: if ${TIMESTAMP}-${SLUG}.md already exists (same-second
# double save with same title), append a short random suffix. Filenames are
# append-only — never overwrite.
FILE="${CHECKPOINT_DIR}/${TIMESTAMP}-${TITLE_SLUG}.md"
if [ -e "$FILE" ]; then
  SUFFIX=$(LC_ALL=C tr -dc 'a-z0-9' < /dev/urandom 2>/dev/null | head -c 4 || printf '%04x' "$$")
  FILE="${CHECKPOINT_DIR}/${TIMESTAMP}-${TITLE_SLUG}-${SUFFIX}.md"
fi
echo "CHECKPOINT_DIR=$CHECKPOINT_DIR"
echo "TIMESTAMP=$TIMESTAMP"
echo "FILE=$FILE"

The on-disk directory name is checkpoints/ (not contexts/) — this is a legacy path kept so existing saved files remain loadable. Users never see it.

Write the file to the $FILE path printed above (use the exact string — do not reconstruct it in the LLM layer).

The file format:

---
status: in-progress
branch: {current branch name}
timestamp: {ISO-8601 timestamp, e.g. 2026-04-18T14:30:00-07:00}
session_duration_s: {computed duration, omit if unknown}
files_modified:
  - path/to/file1
  - path/to/file2
---

## Working on: {title}

### Summary

{1-3 sentences describing the high-level goal and current progress}

### Decisions Made

{Bulleted list of architectural choices, trade-offs, and reasoning}

### Remaining Work

{Numbered list of concrete next steps, in priority order}

### Notes

{Gotchas, blocked items, open questions, things tried that didn't work}

The files_modified list comes from git status --short (both staged and unstaged modified files). Use relative paths from the repo root.

After writing, confirm to the user:

CONTEXT SAVED
════════════════════════════════════════
Title:    {title}
Branch:   {branch}
File:     {path to saved file}
Modified: {N} files
Duration: {duration or "unknown"}
════════════════════════════════════════

Restore later with $plan --mode Discovery --module context-restore.

---

List flow

Step 1: Gather saved contexts

eval "$($GSTACK_BIN/gstack-slug 2>/dev/null)" && mkdir -p "${GSTACK_HOME:-$HOME/.gstack}"/projects/${PROJECT_ID:-unknown}
eval "$($GSTACK_BIN/gstack-paths)"
CHECKPOINT_DIR="$GSTACK_STATE_ROOT/projects/${PROJECT_ID:-unknown}/checkpoints"
if [ -d "$CHECKPOINT_DIR" ]; then
  echo "CHECKPOINT_DIR=$CHECKPOINT_DIR"
  # Use find + sort instead of ls -1t: filename YYYYMMDD-HHMMSS prefix is the
  # canonical order (stable across copies/rsync; mtime is not), and empty-result
  # behavior is clean (no files → no output, no "lists cwd" fallback).
  find "$CHECKPOINT_DIR" -maxdepth 1 -name "*.md" -type f 2>/dev/null | sort -r
else
  echo "NO_CHECKPOINTS"
fi

Step 2: Display table

Default behavior: Show saved contexts for the current branch only.

If the user passes --all (e.g., $plan --mode Discovery --module context-save list --all), show contexts from all branches.

Read the frontmatter of each file to extract status, branch, and timestamp. Parse the title from the filename (the part after the timestamp).

Present as a table:

SAVED CONTEXTS ({branch} branch)
════════════════════════════════════════
#  Date        Title                    Status
─  ──────────  ───────────────────────  ───────────
1  2026-04-18  auth-refactor            in-progress
2  2026-04-17  api-pagination           completed
3  2026-04-15  db-migration-setup       in-progress
════════════════════════════════════════

If --all is used, add a Branch column:

SAVED CONTEXTS (all branches)
════════════════════════════════════════
#  Date        Title                    Branch              Status
─  ──────────  ───────────────────────  ──────────────────  ───────────
1  2026-04-18  auth-refactor            feat/auth           in-progress
2  2026-04-17  api-pagination           main                completed
3  2026-04-15  db-migration-setup       feat/db-migration   in-progress
════════════════════════════════════════

If there are no saved contexts, tell the user: "No saved contexts yet. Run $plan --mode Discovery --module context-save to save your current working state."

---

Important Rules

• Never modify code. This skill only reads state and writes the context file.
• Always include the branch name in frontmatter — critical for cross-branch $plan --mode Discovery --module context-restore.
• Saved files are append-only. Never overwrite or delete existing files. Each save creates a new file.
• Infer, don't interrogate. Use git state and conversation context to fill in the file. Only use AskUserQuestion if the title genuinely cannot be inferred.
• This is a gstack skill, not a Claude Code built-in. When the user types $plan --mode Discovery --module context-save, invoke this skill via the Skill tool. The old /checkpoint name collided with Claude Code's native /rewind alias — the rename fixed that.

Upstream judgment port: PR #679

Match the user language

User-language rule

Write questions, progress updates, reports, and artifacts in the language used by the user. Source material, code identifiers, commands, and quotations may remain in their original language when translating them would reduce accuracy.