engram-echo 0.1.2

Persistent memory for Claude Code — knowledge graph in Obsidian vault

🧠 Engram

Persistent memory for Claude Code — your coding sessions become a knowledge graph

Like sleep consolidates human memory, /engram consolidates your coding sessions into reusable knowledge.

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✨ What It Does

You work in Claude Code as usual. When you're done, run /engram. That's it.

You: /engram

CC: Analyzing session... Found 5 entities, 3 relations.
    ✅ Saved to vault: STDERR_PIPE_BLOCKING, CLAUDE_SLACK_BRIDGE, ...
    📝 Daily note: 2026-04-06.md

Behind the scenes:

CC Session → /engram → Entity Extraction → Knowledge Graph → Obsidian Vault
                        (CC as LLM)        (NetworkX)       (Markdown + [[wikilinks]])

Your knowledge accumulates across sessions. Query it anytime:

You: /engram-query how did I fix the stderr bug?

CC: Found STDERR_PIPE_BLOCKING → Bug where claude process stderr fills 64KB
    pipe buffer, blocking stdout. Fixed by adding _drain_stderr async task.
    Related: [[CLAUDE_SLACK_BRIDGE]]

🏗️ Architecture

Built on the OODA loop — the same decision framework used by fighter pilots:

Phase	What	How
🔍 Observe	Capture session conversations	CC session JSONL parser
🧭 Orient	Extract entities & relations	CC does entity extraction — no external API
🎯 Decide	Consolidate memory	7-stage: replay → feedback → integrate → prune → community → abstract → lint
⚡ Act	Persist to vault	Obsidian markdown + NetworkX GraphML

Zero External Dependencies

• No API keys — CC itself is the LLM
• No vector database — graph-only retrieval with CC entity routing
• No Docker — just Python + networkx
• No cloud services — everything runs locally

📦 Installation

Prerequisites

• Claude Code installed
• Python 3.10+

From PyPI

pip install engram-echo
claude plugin marketplace add https://github.com/qianheng-aws/engram.git
claude plugin install engram@engram-echo

From source

git clone https://github.com/qianheng-aws/engram.git
cd engram
pip install -e .
claude plugin marketplace add ./
claude plugin install engram@engram-echo

Vault, config, and CLAUDE.md prompt all auto-initialize on first use.

Optional:

• engram init ~/custom-vault — use a custom vault path (default: ~/.engram/vault)
• engram auto on — auto-capture sessions on exit

🎮 Commands

Command	Description
/engram	Extract entities and relations from current session
/engram-full	Full consolidation: replay → feedback → integrate → prune → community → abstract → lint
/engram-feedback	Process human corrections from Obsidian callouts
/engram-community	Detect and summarize knowledge clusters (Louvain)
/engram-status	Show vault statistics, graph analysis, and pending sessions
/engram-query <question>	Search knowledge graph (keyword + graph traversal)
/engram-on	Enable auto-capture on session end
/engram-off	Disable auto-capture

/engram vs /engram-full

	/engram	/engram-full
Stages	Replay only	All 6 stages + lint
Speed	Fast (one extraction)	Slower (multi-step)
When	Every session	Auto-triggered when needed

Auto-consolidation: After each /engram, the CLI tracks how many replays have occurred since the last full run. When thresholds are reached, /engram will remind you (tier 1) or automatically escalate to a full consolidation (tier 2). Thresholds are configurable in ~/.engram/config.json:

{
  "consolidation": {
    "remind_after_replays": 10,
    "remind_after_days": 7,
    "force_after_replays": 15,
    "force_after_days": 14
  }
}

🌙 Consolidation Stages

┌──────────┐    ┌──────────┐    ┌───────────┐    ┌─────────┐    ┌───────────┐    ┌──────────┐    ┌────────┐
│  Replay  │ →  │ Feedback │ →  │ Integrate │ →  │  Prune  │ →  │ Community │ →  │ Abstract │ →  │  Lint  │
│          │    │          │    │           │    │         │    │           │    │          │    │        │
│ Extract  │    │  Human   │    │  Merge    │    │ Decay   │    │  Cluster  │    │ Discover │    │ Verify │
│ entities │    │  review  │    │  dupes    │    │ old     │    │  & label  │    │ patterns │    │ vault  │
└──────────┘    └──────────┘    └───────────┘    └─────────┘    └───────────┘    └──────────┘    └────────┘

• Replay — CC extracts entities/relations from session → writes to graph + daily note
• Feedback — Scans entity files for [!correction]/[!merge]/[!delete] callouts left by the user in Obsidian → CC applies fixes
• Integrate — Detects duplicate entities (token similarity) → CC decides merge
• Prune — Scores entities by decay (30-day half-life) → archives stale ones
• Community — Louvain clustering on the graph → CC titles and summarizes each cluster
• Abstract — Analyzes daily notes → discovers behavioral patterns (e.g., "user always debugs by observe → hypothesize → verify")
• Lint — Validates vault consistency: GraphML ↔ markdown sync, dead wikilinks, orphan nodes, frontmatter completeness

Human Feedback (Obsidian)

The Feedback stage processes corrections you leave directly in entity files. In Obsidian:

1. Open any entity file (e.g., entities/concepts/STDERR_PIPE_BLOCKING.md)
2. Add a callout — either Cmd+P → search "callout", or type the syntax directly:

> [!correction] More accurate description
> Actually the buffer limit is 64KB, not 32KB

> [!merge] Should be same as ASYNC_DRAIN_STDERR

> [!delete] False extraction, not a real entity

3. Run /engram-feedback (or /engram-full) — CC reads the callouts, applies fixes, and removes them

🗂️ Vault Structure

Open the vault in Obsidian to get an interactive knowledge graph:

1. Install Obsidian from obsidian.md
2. Open Obsidian → Open folder as vault → In the file picker, press Cmd+Shift+G and type ~/.engram/vault
   • Alternatively, use a visible path: engram init ~/engram/vault
3. Toggle Graph View (Ctrl/Cmd + G) to see your knowledge graph

Entity nodes colored by type, with tags, wikilinks, and Graph View visualization

~/.engram/vault/
├── 📁 entities/              # Knowledge graph nodes
│   ├── people/               #   PERSON entities
│   ├── concepts/             #   Bugs, patterns, designs
│   ├── projects/             #   Repos, packages
│   ├── tools/                #   Libraries, frameworks
│   └── orgs/                 #   Teams, companies
├── 📁 relations/             # Edge table with weights
├── 📁 communities/           # Louvain cluster summaries
├── 📁 groups/                # Hyperedge MOC (Map of Content) files
├── 📁 daily/                 # Session summaries by date
├── 📁 patterns/              # Discovered behavioral patterns
└── 📁 _meta/                 # System data (GraphML, queue, lock)

Entity Example

---
entity_type: CONCEPT
tags:
  - entity/concept
aliases:
  - "Stderr Pipe Blocking"
created: 2026-04-03
last_updated: 2026-04-03
degree: 1
cssclasses:
  - entity
  - concept
---

# STDERR_PIPE_BLOCKING

Bug in claude-slack-bridge where claude process writes verbose logs
to stderr but daemon never reads it, causing 64KB buffer to fill
and block the entire process. Fixed by adding _drain_stderr task.

## Relations

- [[CLAUDE_SLACK_BRIDGE]] `PROJECT` — Bridge had this bug causing sessions to hang (weight: 0.8)

Every entity links to related entities via [[wikilinks]] — Obsidian renders these as an interactive graph. Tags, aliases, and cssclasses enable Dataview queries and Graph View styling.

🔧 Design Decisions

Decision	Why
CC as LLM	No API keys needed. CC extracts entities directly.
Graph-only retrieval	No embeddings. CC picks relevant entities from the full list. Scales to ~2000 entities.
nano-graphrag reference	Reused prompt templates and storage format, not runtime.
Obsidian-native	All output is valid Obsidian markdown. Open vault → instant graph view.
Description cap	Keep first + latest description only. Prevents infinite growth.
File lock	fcntl.LOCK_EX + read-merge-write prevents concurrent corruption.

🛠️ CLI Reference

engram init [PATH]                              # Initialize vault + register in ~/.claude/CLAUDE.md
engram auto [on|off|status]                     # Toggle auto-capture on session end
engram status                                   # Vault statistics + hub entities + density
engram query --question "..."                   # Search graph
engram replay --stdin                           # Process extracted entity/relation JSON
engram integrate                                # Detect duplicate entities
echo '<json>' | engram integrate --stdin        # Execute merges
engram prune                                    # Report decay scores
echo '<json>' | engram prune --stdin            # Archive entities
engram community                                # Detect knowledge clusters
echo '<json>' | engram community --stdin        # Save community summaries
engram abstract                                 # Gather data for pattern discovery
echo '<json>' | engram save-pattern --stdin     # Save discovered patterns
engram feedback                                 # Scan entity files for correction callouts
echo '<json>' | engram feedback --stdin         # Apply corrections/merges/deletes
engram context                                  # Compact summary for system prompt injection
engram lint                                     # Validate vault consistency
engram consolidation                            # Show consolidation tracking state
engram consolidation --reset                    # Reset counter (after full consolidation)
engram install                                  # Re-register in ~/.claude/CLAUDE.md (auto on init)
engram uninstall                                # Remove from ~/.claude/CLAUDE.md
# All commands use the vault from last `engram init`. Override with --vault PATH.

📄 License

MIT — do whatever you want with it.

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Built in one afternoon with Claude Code. The tool that remembers itself. 🐾