MemoryPilot

The most advanced MCP memory server. Period.

_{Hybrid search (BM25 + multilingual-e5-small RRF) · 100+ languages · Temporal Knowledge Graph · AAAK compression (5-10x token savings) · GraphRAG · Chunked RAG · Auto-Compaction · Auto-Classification · Memory Capsules · Project brain · HTTP API · Single binary · Zero API calls}

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Why

AI coding assistants forget everything between sessions. MemoryPilot gives them persistent, searchable memory with project awareness, semantic understanding, and automatic knowledge organization. Built-in AAAK compression and memory capsules reduce token consumption by 5-10x when loading context. Every memory is auto-classified with the right importance, kind, and TTL on insert. The database compacts itself automatically — zero maintenance.

Benchmarks

LongMemEval-S (ICLR 2025) — Academic Standard

Evaluated on 470 questions from the LongMemEval benchmark (ICLR 2025), the standard academic dataset for long-term memory retrieval. Turn-level granularity, ~50 sessions per haystack, all features active.

Metric	MemoryPilot v4.0	MemPalace v3.1	Delta
R@5	97.0%	96.6%	+0.4%
R@10	98.5%	~97%¹	+1.5%
NDCG@10	94.0%	88.9%	+5.1%
MRR	92.5%	~87%¹	+5.5%

¹ MemPalace does not publish R@10 or MRR. Estimates based on their reported per-category scores. MemPalace benchmarks raw ChromaDB retrieval — none of the Palace architecture (wings, rooms, closets) is exercised (source).

By Category (470 questions)

Category	R@5	R@10	NDCG@10	MRR
single-session-user (64)	100%	100%	99.0%	98.8%
single-session-assistant (56)	100%	100%	98.4%	97.9%
multi-session (121)	100%	100%	95.8%	94.4%
knowledge-update (72)	100%	100%	98.3%	97.7%
temporal-reasoning (127)	91.3%	96.1%	89.8%	87.8%
single-session-preference (30)	90.0%	93.3%	75.3%	69.3%

Search Quality — Real-World (500 memories, 30 scenarios)

Metric	MemoryPilot v4.0	MemPalace v3.1 (raw)	Quantum Memory Graph
R@5	100%	96.6%	93.4%
R@10	100%	N/A	93.4%
NDCG@10	95.6%	88.9%	90.8%
Cluster Coherence	96.7%	N/A	N/A
Multilingual	100+ languages	English only	English only
AAAK Compression	5-10x (no recall loss)	30x (recall drops to 84.2%)	N/A
Avg Search Latency	~14 ms	N/A	~80 ms
Binary Size	22 MB	~500 MB (Python+ChromaDB)	1.5 GB
Dependencies	0 (single binary)	Python + ChromaDB + SQLite	Python + ONNX

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vs the best MCP memory servers:

Feature	MemoryPilot v4.0	MemPalace v3.1	Mem0
Search	Hybrid BM25 + multilingual-e5-small RRF (384-dim)	ChromaDB cosine (all-MiniLM-L6-v2)	Vector search (cloud API)
Embeddings	multilingual-e5-small (100+ languages, local ONNX)	all-MiniLM-L6-v2 (English only)	OpenAI API calls (external)
Multilingual	100+ languages native (FR, EN, ES, DE, JA, ZH...)	English only	Depends on API
Knowledge Graph	Temporal triples with validity + confidence	Temporal triples (SQLite)	Basic graph (no temporal)
GraphRAG	Auto entity extraction + graph traversal + combinatorial reranker	No	No
Chunked RAG	Transcript auto-chunking + auto-distillation (8 types)	Conversation chunking by exchange	No
Compression	AAAK + Memory Capsules (5-10x token savings)	AAAK dialect (experimental, regresses recall to 84.2%)	No
Auto-Classification	Zero-shot kind/importance/TTL on insert	No	No
Auto-Compaction	GC triggers automatically at 500+ memories	No	No
Memory Capsules	Compress old memories into dense summaries	No	No
Memory Pinning	Pin critical memories — always in recall, GC-proof	No	No
Graph Traversal	Find related memories via KG (depth 1-3)	No	No
Bulk Operations	Delete by kind/project/tag/age with safety guards	No	No
Health Dashboard	Memory distribution, stale count, orphans, DB size	No	No
Dedup Detection	Jaccard similarity scan for near-duplicates	No	No
Person detection	Auto-detects team members from text	No	No
Self-Healing	Background auto-linting loop	No	No
Garbage collection	Heuristic merge + scoring + orphan cleanup	No	Basic TTL
Project brain	Yes, with team members (<1500 tokens)	No	No
File watcher	Context boost from recent edits	No	No
Deduplication	Content hash (exact) + Jaccard 85% (fuzzy)	Basic hash	Embedding similarity
HTTP API	Multi-threaded REST server (optional)	No	Cloud hosted
Memory types	13 types, importance 1-5	Wings/Rooms hierarchy	1 type
MCP tools	36 tools	19 tools	N/A
Privacy	100% local, zero API calls	100% local	Cloud dependent
Language	Rust (single binary, zero deps)	Python (pip install)	SaaS
Startup	1-2 ms	~5 ms	N/A (cloud)
Binary	22 MB single binary	Python + ChromaDB (~500 MB installed)	SaaS
Storage	SQLite WAL + FTS5 + connection pool	ChromaDB	Cloud DB
Concurrency	Lazy embedding thread + read pool + debounced cleanup	Single-threaded	Single-threaded

The 9 Pillars

1. Hybrid Search (BM25 + fastembed RRF)

Every memory gets a 384-dimension transformer embedding on insert via fastembed (multilingual-e5-small, local ONNX inference — supports 100+ languages including French, English, Spanish, German, Japanese, Chinese — no API calls, no external services). Search runs both BM25 full-text and cosine similarity in parallel, then merges results with Reciprocal Rank Fusion.

Results are boosted by importance weighting, knowledge graph link density, file watcher context, and penalized for expired knowledge triples.

Performance optimizations:

• Lazy embedding: add_memory returns instantly, embeddings computed in background thread
• LRU cache (64 entries): repeated search queries skip embedding computation
• Read connection pool (4 connections): concurrent vector searches don't block writes
• Content hashing (FNV-1a): backfill skips unchanged memories

2. Temporal Knowledge Graph

A full knowledge graph with temporal validity. Facts have valid_from / valid_to dates and confidence scores. When facts become outdated, they are invalidated rather than deleted — giving the AI a timeline of how knowledge evolved.

Entities (technologies, files, components, people) are automatically extracted from memory content and linked bidirectionally. Search results from memories with all-expired triples are penalized.

5 dedicated KG tools: kg_add, kg_invalidate, kg_query, kg_timeline, kg_stats

3. GraphRAG

Every memory is automatically analyzed for entities: technologies, file paths, components, projects, and people. Entities are stored in a dedicated table. Memories sharing entities are auto-linked with inferred relationship types (resolves, implements, depends_on, deprecates...).

When searching, MemoryPilot traverses the knowledge graph from the top matches to pull in related context — e.g., finding the architecture decision that led to a specific bug fix. A combinatorial reranker then selects the best cluster of connected memories rather than independent top-K results, producing cohesive context (94% cluster coherence). Tuned RRF fusion (k=40), exact term coverage boost, smart FTS tokenization, query-time KG expansion, temporal recency, and importance tiebreakers push NDCG@10 to 94% with perfect R@5/R@10.

4. Chunked RAG (Transcripts)

Save full conversation transcripts without polluting the LLM context window. The add_transcript tool automatically chunks large texts into ~2000 character blocks and links them together. Chunks are excluded from recall but fully searchable.

Auto-distillation extracts structured memories from transcripts: decision, preference, todo, bug, milestone, problem, and note. Smart disambiguation: a segment mentioning both a bug and its resolution is classified as milestone, not bug.

Supports session_id, thread_id, window_id for multi-window memory scoping.

5. AAAK Compression

Inspired by MemPalace's symbolic memory language. When compact: true is passed to recall or get_project_brain, output is compressed ~3x using a terse, pipe-separated format:

[DEC:5] Use Clerk over Auth0 | tags:auth,stack | proj:MyApp
[PREF:4] Always use TypeScript strict mode | tags:typescript

6. Self-Healing (Auto-Linter)

MemoryPilot watches your files. When you save a Rust, Svelte, or TypeScript file, it lints in the background. Compilation errors are automatically stored as bug memories with the exact stack trace. When the error is fixed, the memory is auto-deleted.

The linter thread reuses a single DB connection for its entire lifetime.

7. Garbage Collection & Auto-Compaction

Old, low-importance memories are scored for cleanup candidacy. Groups of related stale memories are merged into condensed summaries using heuristic keyword extraction. Orphaned links and entities are cleaned. DB is vacuumed after significant deletions.

Auto-compaction triggers automatically when the memory count exceeds 500: the GC runs in the background after add_memory, debounced to once per 5 minutes. Zero manual intervention.

Memory Capsules (compact_memories tool): compress old low-importance memories into dense ~100-200 token capsules. Credentials and architecture decisions are never compressed. Capsules preserve Knowledge Graph links, giving you 5-10x token savings on aged memories without recall loss.

8. Zero-Shot Auto-Classification

Every memory is automatically classified on insert when the caller doesn't specify kind or importance. Pattern-based heuristics detect:

• Credentials (API keys, secrets) → importance 5, no TTL
• Architecture decisions → importance 5
• Preferences/patterns → importance 4
• Bugs → importance 3, TTL 90 days
• TODOs → importance 2, TTL 30 days
• Code snippets → importance 2
• Milestones → importance 4

No LLM needed — pure regex + keyword heuristics. The AI can still override by passing explicit kind and importance.

9. Project Brain

One tool call returns a dense JSON snapshot of a project under 1500 tokens: tech stack, architecture decisions, active bugs, recent changes, key components, and team members (auto-detected person entities). Supports compact: true for AAAK compression.

Install

One-liner (recommended)

git clone https://github.com/Soflution1/MemoryPilot.git && cd MemoryPilot && ./install.sh

The installer builds MemoryPilot, installs the binary to ~/.local/bin/, detects your IDEs, and configures each one automatically.

Supported IDEs:

IDE	Config file	Auto-configured
Cursor	~/.cursor/mcp.json	✓ (stdio)
VS Code	~/.vscode/mcp.json	✓ (stdio)
Claude Desktop	~/Library/Application Support/Claude/claude_desktop_config.json	✓ (stdio)
Windsurf	~/.codeium/windsurf/mcp_config.json	✓ (stdio)
Claude Code	claude mcp add	✓ (CLI)
Codex	codex mcp add	✓ (CLI)
ChatGPT Desktop	Settings → Apps → Create	via HTTP (see below)

The script is idempotent — run it again to update without breaking existing MCP configs.

ChatGPT Desktop

ChatGPT requires a remote MCP endpoint. Start the HTTP server, then add it as a custom connector:

MemoryPilot --http 7437

In ChatGPT: Settings → Apps → Create → URL: http://localhost:7437/mcp

Manual install

git clone https://github.com/Soflution1/MemoryPilot.git
cd MemoryPilot
cargo build --release --features http
cp target/release/MemoryPilot ~/.local/bin/
chmod +x ~/.local/bin/MemoryPilot
xattr -cr ~/.local/bin/MemoryPilot  # macOS only

Then add MemoryPilot to your IDE's MCP config manually (see table above for file paths).

How it works

That's it. MemoryPilot automatically injects a dynamic System Prompt into your IDE on startup. The AI will proactively call add_memory in the background to store your architecture decisions, API keys, and bug fixes without manual intervention. All configured IDEs share the same memory database.

For ChatGPT or any MCP client that needs HTTP: run MemoryPilot --http to expose the Streamable HTTP endpoint at /mcp.

Or use via McpHub for SSE transport with all your other MCP servers.

First run

# If upgrading from v1 (JSON files):
MemoryPilot --migrate

# Compute embeddings for existing memories:
MemoryPilot --backfill

# Force re-embed all (skips unchanged via content hash):
MemoryPilot --backfill-force

MCP Tools (30)

Core

Tool	Description
recall	Start here. Loads all context in one shot: project memories, scoped thread/window memories, preferences, critical facts, patterns, decisions, global prompt. Supports mode = safe/default/full, compact = true for AAAK compression.
get_project_brain	Instant project summary (<1500 tokens): tech stack, architecture, bugs, recent changes, components, team members. Supports compact = true.
search_memory	Hybrid BM25 + fastembed RRF search, boosted by importance, graph links, and file watcher context. Batched triple scoring.
get_file_context	Memories related to recently modified files in working directory.

Memory CRUD

Tool	Description
add_memory	Store with lazy embedding, auto-dedup (hash exact + Jaccard 85%), auto entity extraction, auto graph linking, auto-classification (kind, importance, TTL inferred from content).
add_memories	Bulk add multiple memories in one call with per-item dedup.
add_transcript	Store a long transcript as chunked archive, auto-distill structured memories (decision, preference, todo, bug, milestone, problem, note).
get_memory	Retrieve by ID.
update_memory	Update content, kind, tags, importance, TTL. Skips re-embedding if content unchanged (hash check).
delete_memory	Delete by ID (cascades to entities and links).
list_memories	List with project/kind filters and pagination.

Knowledge Graph

Tool	Description
kg_add	Add a fact triple (subject → predicate → object) with optional validity period and confidence score.
kg_invalidate	Mark a triple as expired (sets valid_to), preserving history.
kg_query	Query all triples related to an entity, with temporal filtering and direction control.
kg_timeline	Chronological history of all triples involving an entity.
kg_stats	Summary statistics: total triples, active, expired, unique subjects/objects.

Project & Config

Tool	Description
get_project_context	Full project context with preferences and patterns.
register_project	Register project with filesystem path for auto-detection.
list_projects	List projects with memory counts.
get_stats	DB statistics: totals, by kind, by project, DB size, hygiene signals.
get_global_prompt	Auto-discover GLOBAL_PROMPT.md from ~/.MemoryPilot/ or project root.
export_memories	Export as JSON or Markdown with importance stars.
set_config	Set config values (e.g. global_prompt_path).

Maintenance

Tool	Description
run_gc	Garbage collection: merge old memories, clean orphans, vacuum. Supports dry_run.
compact_memories	Compress old low-importance memories into dense capsules (~100-200 tokens). Credentials/architecture never compressed.
cleanup_expired	Remove expired TTL memories (debounced — runs max once per 60s).
pin_memory	Pin a critical memory — always included in recall, never garbage collected.
unpin_memory	Unpin a previously pinned memory, making it eligible for GC again.
find_related	Find all memories related to a given ID via Knowledge Graph traversal (depth 1-3).
bulk_delete	Delete memories by kind, project, tag, age, or importance. Never touches pinned memories.
get_memory_health	Health report: distribution by kind/project/importance, stale count, orphans, compression potential, DB size.
dedupe_report	Find potential duplicates via Jaccard similarity for manual review.
benchmark_recall	Recall quality benchmark with golden scenarios.
benchmark_search	Search quality benchmark: R@5, R@10, NDCG@10, cluster coherence, latency.
migrate_v1	Import from v1 JSON files.

Memory Types

fact · preference · decision · pattern · snippet · bug · credential · todo · note · milestone · architecture · problem · transcript_chunk

Each memory has importance (1-5), optional TTL, tags, project scope, content hash, and auto-generated embedding + entity links.

CLI

MemoryPilot                          # Start MCP stdio server
MemoryPilot --backfill               # Compute missing embeddings
MemoryPilot --backfill-force         # Re-embed all (skips unchanged via hash)
MemoryPilot --benchmark-recall       # Run recall quality benchmark
MemoryPilot --benchmark-search       # Search quality: R@5, R@10, NDCG@10, cluster coherence
MemoryPilot --benchmark-longmemeval  # LongMemEval-S (ICLR 2025) academic retrieval benchmark
MemoryPilot --http 7437              # Start HTTP REST server (requires --features http)
MemoryPilot --migrate                # Import v1 JSON data
MemoryPilot --version                # Show version
MemoryPilot --help                   # Show help

HTTP API

When built with --features http, MemoryPilot exposes a multi-threaded REST API (4 worker threads, each with its own DB connection):

# Health check
curl http://localhost:7437/health

# Call any MCP tool
curl -X POST http://localhost:7437/tools/call \
  -H 'Content-Type: application/json' \
  -d '{"name": "search_memory", "arguments": {"query": "auth setup", "limit": 5}}'

Architecture

src/main.rs        — CLI + MCP stdio server + file watcher init + HTTP server init
src/db.rs          — SQLite engine: hybrid search, CRUD, KG, GC, brain, recall, lazy embed, connection pool
src/tools.rs       — 36 MCP tool definitions + handlers
src/protocol.rs    — JSON-RPC types
src/embedding.rs   — fastembed (multilingual-e5-small) transformer embeddings, LRU cache
src/graph.rs       — Entity extraction (tech, files, components, people) + relation inference + graph traversal
src/gc.rs          — GC scoring, heuristic memory merging, stopwords
src/watcher.rs     — File system watcher + auto-linter with persistent DB connection
src/http.rs        — Optional multi-threaded HTTP REST server (feature-gated)

Database Schema

memories           — id, content, kind, project, tags, importance, embedding (BLOB),
                     content_hash, expires_at, last_accessed_at, access_count, metadata
memories_fts       — FTS5 virtual table (content, tags, kind, project)
memory_entities    — memory_id, entity_kind, entity_value, valid_from, valid_to
memory_links       — source_id, target_id, relation_type, valid_from, valid_to, confidence
knowledge_triples  — id, subject, predicate, object, valid_from, valid_to, confidence, source_memory_id
projects           — name, path, description
config             — key/value store

Performance

Metric	Value
Binary size	22 MB
Startup	1-2 ms
Search (hybrid RRF + reranker)	~10 ms (500 memories)
add_memory latency	<1 ms (lazy embed)
Embedding quality	Transformer 384-dim (multilingual-e5-small, 100+ languages)
Backfill (1000 memories)	~30s (skips unchanged via hash)
RAM	~15 MB
Read concurrency	4 pooled connections
Runtime dependencies	None (ONNX bundled)

Optimizations

• Lazy embedding: add_memory inserts with NULL embedding, background thread computes and updates asynchronously
• Content hashing (FNV-1a): --backfill-force skips memories whose content hasn't changed
• LRU embedding cache (64 entries): repeated search queries reuse cached embeddings
• Read connection pool (4 connections): concurrent vector searches don't block writes
• WAL mode: SQLite Write-Ahead Logging for concurrent read/write
• Batched scoring: knowledge triple counts and link boosts fetched in single queries, not N+1
• Debounced cleanup: expired memory cleanup runs max once per 60 seconds
• Prepared statements: graph traversal prepares SQL once, not per node
• Tuned RRF fusion: k=40 for sharper top-K discrimination vs standard k=60
• Exact term coverage boost: +10% when 80%+ of query terms appear in memory content
• Combinatorial reranker: greedy subgraph selection, conservative +5% per connection (cap 15%)
• KG query expansion: post-retrieval scoring boost from knowledge graph related terms (+4% per entity, cap 15%)
• Temporal recency: gentle +5% for memories from last 3 days, decaying over 30 days
• Importance tiebreaker: ±3% per level — never overrides relevance signal
• Auto-compaction: GC triggers automatically when memory count > 500, debounced to once per 5 minutes
• Memory capsules: old low-importance memories compressed into ~100-200 token summaries (5-10x savings)
• Zero-shot auto-classification: pattern-based heuristics assign kind, importance, and TTL on insert without LLM

Run Benchmarks Yourself

MemoryPilot --benchmark-search --scenario-limit 30    # R@5, R@10, NDCG@10, cluster coherence, latency
MemoryPilot --benchmark-recall --scenario-limit 12    # top1/top5 hit rate, cross-project leak, credential safety
MemoryPilot --benchmark-longmemeval [PATH] [--limit N] # LongMemEval-S (ICLR 2025) academic benchmark

The LongMemEval benchmark downloads the LongMemEval-S dataset and evaluates retrieval quality across 470 questions with turn-level granularity. Results are output as JSON with per-category breakdowns.

Storage

• Database: ~/.MemoryPilot/memory.db
• Global prompt: ~/.MemoryPilot/GLOBAL_PROMPT.md
• Fastembed model cache: ~/.fastembed_cache/ (downloaded on first run)

License

Soflution Source Available License — free to use, not to fork or modify. See LICENSE for details.

Built by SOFLUTION LTD