📓 Diary: Logging Session...

Document what was accomplished in each CC session for future recall.

Activation

When this skill activates, output:

📓 Diary: Logging session...

Then execute the protocol below.

Context Guard

Context	Status	Priority
User says "save diary", "log session", "write diary"	ACTIVE: write diary	P1
User explicitly says they're done ("that's it", "wrapping up")	ACTIVE, suggest diary if work was done	P2
Multi-agent session (Builder/Reviewer role)	DORMANT: Manager handles diary	none
Mid-session, user is actively coding	DORMANT, don't interrupt flow	none
Casual conversation, no code changes made	DORMANT: nothing to log	none
User asks to recall past sessions ("what did we do")	DORMANT, Echo handles recall, not Diary	none
User says "save project" or "handoff"	DORMANT, Project skill handles this	none
Session just started, no work yet	DORMANT: nothing to log	none

When NOT to Fire

• Do NOT fire autonomously. Only activate when the user explicitly requests it ("save diary", "log session", "wrapping up").
• Multi-agent sessions: If you are operating as Builder, Reviewer, or any non-Manager agent in a multi-agent session, do NOT fire diary. Only the Manager or a standalone session should trigger diary.
• No work done: If no meaningful changes were made (no commits, no file edits), skip diary.

Reminders

When the user asks to save a diary, keep these in mind:

Temptation	Why it matters
"Nothing important happened"	Even small decisions have context worth capturing.
"Commits capture everything"	Commits don't capture decisions, blockers, or next steps.
"Skip the handoff section"	Handoffs are the most valuable part for session continuity.

Protocol

Never pass a JSON payload as a quoted command-line argument. Write it to a file and pipe it in with the dash sentinel, as every command below shows. On Windows, cmd.exe treats single quotes as ordinary characters, so a redirection operator anywhere in a quoted payload is executed rather than passed.

All JSON field values must be plain strings. Never pass arrays or objects. If multiple items (files, commits, decisions), join them as a comma-separated string.

1. Summarize the session:

   • Project name and working directory
   • Date and approximate duration
   • What was built or changed
   • Key files created or modified
   • Commits made (hashes and messages)
   • Decisions made and why
   • Problems encountered and solutions

2. Check git log for commits:

   git log --oneline -10
   

3. Format the diary entry:

   # Session Diary: {project}, {date}
   
   ## Accomplished
   - Item 1...
   
   ## Files Changed
   - path/to/file.ts: description
   
   ## Commits
   - abc1234 Message
   
   ## Decisions
   - Decision: reason
   
   ## Next Steps
   - What to do next
   
   ## Session Handoff
   **In Progress:** [what was actively being worked on when session ended]
   **Uncommitted Changes:** [list any unstaged/uncommitted work, or "None"]
   **Pick Up Here:** [exact instruction for next session, specific enough to start cold]
   **Session Context:** [anything important that isn't captured elsewhere: temp decisions, debugging state, gotchas discovered]
   

4. Save to SQLite database (primary storage):

   Write the payload to a file, then pipe it in with - as the argument. A payload on stdin is never seen by the shell's parser, so a redirection operator inside your prose cannot be read as one.

   cat session.json | python "${CLAUDE_PLUGIN_ROOT}/db/memstack-db.py" add-session -
   

   The store is ~/.memstack/memstack.db, one file per user, never a file beside the script. Every command prints the path it used on stderr as memstack-db: store <path>, so a session can confirm where it wrote instead of assuming.

   session.json contains:

   {"project":"<name>","date":"<YYYY-MM-DD>","accomplished":"<bullets>","files_changed":"<bullets>","commits":"<bullets>","decisions":"<bullets>","problems":"<bullets>","next_steps":"<bullets>","duration":"<estimate>","raw_markdown":"<full text>"}
   

5. Save insights for cross-project search:

   Same form: write the payload to a file, pipe it in, - as the argument. Insight text is prose, so it must never travel on the command line.

   cat insight.json | python "${CLAUDE_PLUGIN_ROOT}/db/memstack-db.py" add-insight -
   

   insight.json contains:

   {"project":"<name>","type":"<type>","content":"<insight>","context":"Session <date>","tags":"<project>"}
   

   Choose <type> deliberately from this vocabulary, do not default to one:

   • gotcha: something that bit us and the fix. Non-obvious behavior a future session would trip on again.
   • lesson: a general rule learned the hard way. Broader than one bug.
   • pattern: a reusable approach or convention that worked.
   • warning: a known hazard to avoid. Not yet a bug, but will be.
   • failed_approach: something tried that did not work, and why. Prevents retrying it.
   • architecture: a structural fact about how a system is built.
   • decision: a choice made and the reasoning. Historical record.

   The first five are procedural: an agent can act on them at retrieval time. architecture and decision are record. When a row could be either, prefer the procedural type.

   Unknown types pass through unchanged but come back as type_unknown in the JSON response, that is the signal to pick a type from the list above.

   CRITICAL: The field name is "content", NOT "insight". Using "insight" will fail with a missing required field error.

6. Update project context with last session date:

   Same form, even though this payload is only metadata. One rule with no exceptions is easier to follow than a rule you have to judge.

   cat context.json | python "${CLAUDE_PLUGIN_ROOT}/db/memstack-db.py" set-context -
   

   context.json contains:

   {"project":"<name>","last_session_date":"<YYYY-MM-DD>"}
   

7. Also save markdown copy to memory/sessions/{date}-{project}.md (export format, human-readable backup). Append a ## FACTS block (see below) as the last section of this markdown.

8. Ingest the FACTS block into the Memory Engine, right after the markdown is written:

python -m memstack_skill_loader.diary_ingest "memory/sessions/{date}-{project}.md"

This parses the ## FACTS block and stores each fact with source_type='diary'.

Read the summary it prints. This step is not fire-and-forget. It reports memory-ingest: N ingested, M duplicate, K skipped into project 'NAME': PATH on stdout, followed by one indented reason per skipped line naming the line number and what was wrong with it. NAME is the namespace the facts were actually written to, derived from the diary's filename, and it is the part to check: a diary filed under an unintended project ingests cleanly and exits 0 while staying invisible to every recall for the real one. When no fact has ever been stored under that namespace the line reads into NEW project 'NAME', which is the cheapest signal that derivation landed somewhere unintended. Pass --project NAME to skip filename derivation entirely when the derived name would be wrong. The exit code classifies the outcome:

Exit	Meaning
0	Nothing was lost: facts ingested, an all-duplicates re-run, or no FACTS block at all (which prints nothing at all).
1	Total loss. The block held lines and not one of them ingested.
2	Store failure. The run aborted at the first bad row; the Memory Engine is broken, not the diary.

If K is not 0, fix those lines in the markdown and run the command again. A skipped line is a fact this session was supposed to hand to the next one and did not, and the most common cause is a | inside a claim. Re-running is safe: facts dedupe on source + subject + claim, so anything already stored comes back as a duplicate rather than being written twice.

A non-zero exit never means the diary failed to save. The markdown and the SQLite row are already written by this point, and ingestion cannot undo them.

FACTS Block: Cross-Session Memory

The ## FACTS block is how a session hands durable, atomic knowledge to future sessions. It is machine-parsed, so the format is fixed. One fact per line:

subject | claim | method [| entities]

• subject: a dotted-path namespace, lowercase (e.g. memstack.dashboard.start, adminstack.portal.auth). Group related facts under a shared prefix.
• claim: exactly one assertion. Keep it self-contained. Must not contain a |.
• method: how you know it, one of: verified (you saw it work / read the code / ran it), reported (stated but unconfirmed), inferred (deduced), assumed (a guess: scored lowest).
• entities: optional 4th field: comma-separated tags this fact touches.

Examples (note the granularity)

## FACTS
memstack.dashboard.start | start_dashboard() in dashboard.py, port 3333, proxy opt-in | verified
memstack.memory.recall-scoring | recall score = confidence * exp(-age/half_life), computed at query time, never stored | verified
adminstack.portal.auth | portal uses Supabase magic-link auth, not passwords | reported | supabase, auth
memstack.memory.corrections | a superseded fact cannot be corrected; corrections extend from the live tip | verified | correction

What to include

• Only facts worth remembering across sessions. Not "ran the tests", that's in the diary body. A fact is something a future session would waste time rediscovering: a port, an entry point, an auth model, a non-obvious constraint.
• Prefer verified over reported. If you actually confirmed it, say so, verified facts are trusted and decay slowest. Don't inflate: an unconfirmed claim is reported.
• Corrections of prior beliefs are the most valuable entries. If this session overturned something an earlier session believed ("the port is 3333, not 8080"; "auth is magic-link, not passwords"), record the corrected claim as a fact, that is exactly the knowledge that stops the team repeating a mistake.

Session File Size Management

The 500-line limit on markdown files is no longer a concern since SQLite is the source of truth. Markdown files in memory/sessions/ are now just human-readable exports. Old markdown files are preserved but not the primary storage.

Inputs

• Current session context
• Project name from working directory or config.json
• Git log for commit history

Outputs

• Session entry in SQLite database
• Insights extracted from decisions
• Markdown backup in memory/sessions/
• Brief confirmation summary

Example Usage

User: "save diary"

📓 Diary: Logging session...

Saved: memory/sessions/2026-02-18-adminstack.md

Project: AdminStack | Duration: ~2 hours
Accomplished: Built CC Monitor page, API routes, setup guide
Commits: 4 (45b4c42, d1c7e11, f6c8e18, f0e793f)
Files changed: 8

This session is now searchable via Echo.

PreCompact Hook: Automatic Compaction Diary

The diary system includes an automatic PreCompact hook that fires before Claude Code compresses the context window. This closes the gap where session context could be lost during long conversations.

Behavior

• Trigger: Fires automatically before every CC context compaction: no user action required
• Output: .claude/diary/{date}-compaction.md, one file per day, appends on multiple compactions
• Flag: Every entry includes COMPACTION_INTERRUPTED so the next session knows context was cut
• Timeout: 15 seconds, fast enough to never block compaction

What It Captures

Data	Source
Uncommitted changes	git status --short
Recent commits	git log --oneline -5
Recent shell commands	Shell history (last 5)
Recently modified files	Files modified since last git operation
Branch and project	Git branch + directory name

How It Differs from Manual Diary

	Manual Diary	PreCompact Diary
Trigger	User says "save diary"	Automatic before compaction
Content	Full narrative with decisions, handoff	Snapshot of working state
Storage	SQLite + memory/sessions/	.claude/diary/ only
Purpose	Session documentation	Context recovery after compaction

Session Resume

When resuming after compaction, check .claude/diary/ for entries with today's date. The COMPACTION_INTERRUPTED flag signals that the previous context was truncated and these files contain the lost state.

Configuration

Hook is registered in .claude/settings.json under PreCompact. Script lives at .claude/hooks/pre-compact.sh. Always exits 0: must never block compaction.

Full Hook System (v3.3.2)

The Diary skill is part of a broader hook system that automates session lifecycle, security, and observability. All hooks follow the same defensive pattern: set -uo pipefail, SCRIPT_DIR resolution, all external commands wrapped with fallbacks, guaranteed exit 0.

Hook Registry: 7 hooks across 5 events

Event	Script	Matcher	Timeout	Purpose
PreToolUse	pre-tool-notify.sh	Write|Edit|MultiEdit|Bash	10s	TTS voice alert before approval prompts
PreToolUse	pre-push.sh	Bash (git push)	60s	Build verification + secrets scan before push
PostToolUse	post-commit.sh	Bash (git commit)	10s	Debug artifact + secrets scan after commit
PostToolUse	post-tool-monitor.sh	Write|Edit|MultiEdit|Bash	10s	Observation capture, logs tool calls to .claude/observations/
SessionStart	session-start.sh	(all)	10s	CLAUDE.md indexing, monitoring ping
SessionStart	session-context-load.sh	(all)	15s	Context injection, last 3 diary + observation summaries → .claude/session-context.md
Stop	session-end.sh	(all)	10s	Monitoring API session-complete ping
PreCompact	pre-compact.sh	(all)	15s	Auto-save diary snapshot before context compaction

Architecture Notes

• Each hook is registered as an independent entry (Option B) in settings.json, giving it its own timeout budget
• PreToolUse hooks can block tool execution (exit 2 = block). All other hooks are non-blocking
• PostToolUse observation monitor writes to .claude/observations/YYYY-MM-DD.md: daily files, append-only
• SessionStart context loader is idempotent: overwrites .claude/session-context.md on each new session
• Both .claude/observations/ and .claude/session-context.md are in .gitignore (ephemeral runtime output)
• All scripts live in .claude/hooks/ and use ${CLAUDE_PROJECT_DIR} for portable path resolution

Level History

• Lv.1: Base: Session logging with git integration. (Origin: MemStack v1.0, Feb 2026)
• Lv.2: Enhanced: Added YAML frontmatter, context guard, 500-line limit with archive, activation message. (Origin: MemStack v2.0 MemoryCore merge, Feb 2026)
• Lv.3: Advanced: SQLite as primary storage, auto-extract insights from decisions, markdown as backup export. (Origin: MemStack v2.1 Accomplish-inspired upgrade, Feb 2026)
• Lv.4: Native: CC rules integration (.claude/rules/diary.md), always-on session logging awareness without skill file read. (Origin: MemStack v3.0-beta, Feb 2026)
• Lv.5: Handoff: Added structured Session Handoff section: in-progress work, uncommitted changes, exact pickup instructions, session context preservation. (Origin: MemStack v3.1, Feb 2026)
• Lv.6: PreCompact: Added automatic PreCompact hook: saves working state snapshot before CC context compaction, captures uncommitted changes, recent commands, and modified files with COMPACTION_INTERRUPTED flag. (Origin: MemStack v3.3.1, Mar 2026)
• Lv.7: Hook System: Documented full 7-hook system across 5 CC lifecycle events: PreToolUse (TTS + pre-push), PostToolUse (post-commit + observation monitor), SessionStart (Headroom + context injection), Stop, PreCompact. (Origin: MemStack v3.3.2, Mar 2026)
• Lv.8: FACTS Ingestion: Added the ## FACTS block, atomic, machine-parsed cross-session knowledge (subject | claim | method | entities) ingested into the Memory Engine via diary_ingest after each save. Fail-open, dedupe-safe, corrections-first. (Origin: MemStack Memory Engine step 4, Jul 2026)