claude-mem-lite is a persistent memory (also called long-term memory or cross-session context) system for Claude Code — Anthropic's CLI coding agent. It runs as an MCP server plus a set of Claude Code hooks, automatically capturing coding observations, decisions, and bug fixes during sessions, then providing hybrid full-text + semantic search to recall them later.
Compared to general-purpose LLM memory frameworks like mem0 or the MCP reference memory server, claude-mem-lite is purpose-built for Claude Code's hook lifecycle: episode batching cuts LLM calls 7–10× vs the original claude-mem (an estimated ~600× lower total cost — see the cost model below; this is an architecture estimate, not a measured benchmark), while the hybrid FTS5 + TF-IDF retriever benchmarks at 0.88 Recall@10 / 0.96 Precision@10.
中文简介:claude-mem-lite 是 Claude Code 的轻量级持久化记忆 / 长期记忆 / 跨会话上下文插件,基于 MCP 协议 + 钩子机制,自动捕获编码会话中的决策、修复和上下文,并通过 FTS5 + TF-IDF 混合检索召回。详见 中文 README。
Zero external services. Single SQLite database. Minimal overhead.
A ground-up redesign of claude-mem, replacing its heavyweight architecture with a smarter, leaner approach.
| claude-mem (original) | claude-mem-lite | |
|---|---|---|
| LLM calls | Every tool use triggers a Sonnet call | Only on episode flush (5-10 ops batched) |
| LLM input | Raw tool_input + tool_output JSON |
Pre-processed action summaries |
| Conversation | Multi-turn, accumulates full history | Stateless single-turn extraction |
| Noise filtering | LLM decides via "WHEN TO SKIP" prompt | Deterministic code-level Tier 1 filter |
| Runtime | Long-running worker process (1.8MB .cjs) | On-demand spawn, exits immediately |
| Dependencies | Bun + Python/uv + Chroma vector DB | Node.js only (3 npm packages) |
| Source size | ~2.3MB compiled bundles | ~50KB readable source |
| Data directory | ~/.claude-mem/ |
~/.claude-mem-lite/ (hidden, auto-migrates) |
For a typical 50-tool-call session (illustrative cost model — the ratios below are architecture estimates derived from batch size, token counts, and model pricing, not a measured end-to-end benchmark):
| claude-mem | claude-mem-lite | Ratio (estimated) | |
|---|---|---|---|
| LLM calls | ~50 (every tool use) | ~5-8 (per episode) | ~7-10x fewer |
| Tokens per call | 1,000-5,000 (raw JSON + history) | 200-500 (summaries only) | ~5-10x smaller |
| Total tokens | ~100K-250K | ~1K-4K | ~50-100x less |
| Model cost | Sonnet ($3/$15 per M) | Haiku ($0.25/$1.25 per M) | ~12x cheaper |
| Combined savings | ~600x lower cost (estimated) |
| Dimension | Winner | Why |
|---|---|---|
| Classification accuracy | Tie | Both produce correct type/title/narrative |
| Noise filtering | lite | Code-level filtering is deterministic; LLM "WHEN TO SKIP" is unreliable |
| Observation coherence | lite | Episode batching groups related edits into one coherent observation |
| Code-level detail | original | Sees full diffs, but rarely useful for memory search |
| Search recall | Tie | Users search semantic concepts ("auth bug"), not code lines |
| Hook latency | lite | Async background workers; original blocks 2-5s per hook |
The original sends everything to the LLM and hopes it filters well. claude-mem-lite filters first with code, then sends only what matters to a smaller model. This is not a downgrade; it's a smarter architecture that produces equivalent search quality at a fraction of the cost.
How claude-mem-lite differs from the major neighbors in the LLM-memory space (verified May 2026):
| claude-mem-lite | mem0 |
MCP reference memory |
claude-mem (original) | |
|---|---|---|---|---|
| Target client | Claude Code only | Any LLM app via SDK | Any MCP client | Claude Code only |
| Capture model | Auto via hooks | Manual memory.add() |
Manual tool calls (create_entities, add_observations) |
Auto via hooks |
| Code-aware retrieval | FTS5 + 100+ synonym pairs (incl. CJK↔EN) | General-purpose | Generic graph nodes | Code-aware |
| Search | Hybrid: FTS5 BM25 + TF-IDF cosine via RRF | Hybrid: semantic + BM25 + entity linking | Knowledge-graph traversal | FTS5 + Chroma vector |
| Storage | Single local SQLite | Pluggable; Qdrant or configurable vector store | Single JSONL file (knowledge graph) | SQLite + Chroma |
| LLM dependency | Haiku per episode (5–10 ops batched) | LLM per add/search op | None (graph CRUD only) | Sonnet per tool call |
| Setup | One command (/plugin install or npx) |
SDK integration + vector store config | MCP install (per-client) | Bun + Python + Chroma |
When to pick which: pick mem0 if you need a memory layer for a non-Claude-Code app (your own agent, multiple LLM providers). Pick the MCP reference memory server if you specifically want a knowledge-graph data model and don't mind invoking memory tools by hand. Pick claude-mem-lite if you want zero-touch automatic capture purpose-built for Claude Code's hook lifecycle, with code-domain retrieval and no external services.
- Automatic capture -- Hooks into Claude Code lifecycle (PostToolUse, SessionStart, Stop, UserPromptSubmit) to record observations without manual effort
- Hybrid search -- FTS5 BM25 + TF-IDF vector cosine similarity, merged via Reciprocal Rank Fusion (RRF). FTS5 handles keyword matching; 512-dim TF-IDF vectors capture semantic similarity for recall beyond exact terms
- Timeline browsing -- Navigate observations chronologically with anchor-based context windows
- Episode batching -- Groups related file operations into coherent episodes before LLM encoding
- Error-triggered recall -- Automatically searches memory when Bash errors occur, surfacing relevant past fixes
- Proactive file history -- When editing a file, automatically shows relevant past observations for that file
- Session summaries -- LLM-generated summaries at session end (via background workers using
claude -p) - Project-scoped context -- Injects recent memory into
CLAUDE.mdand session startup for immediate context - Observation types -- Categorized as
decision,bugfix,feature,refactor,discovery, orchange - Importance grading -- LLM assigns 1-3 importance levels (routine / notable / critical) to each observation
- Observation relations -- Bidirectional links between related observations based on file overlap
- User prompt capture -- Records user prompts via UserPromptSubmit hook for intent tracking
- Read file tracking -- Tracks files read during sessions for richer episode context
- Zero data loss -- If LLM fails, observations are saved with degraded (inferred) metadata instead of being discarded
- Two-tier dedup -- Jaccard similarity (5-minute window) + MinHash signatures (7-day cross-session window) prevent duplicates
- Synonym expansion -- Abbreviations like
K8s,DB,authautomatically expand to full forms in FTS5 search (100+ pairs including CJK↔EN cross-language mappings) - CJK synonym extraction -- Unsegmented Chinese text is scanned for known vocabulary words (数据库→database, 搜索→search, etc.) enabling cross-language memory recall
- Stop-word filtering -- English stop words filtered from both TF-IDF vocabulary (reclaiming ~18% of vector dimensions) and FTS queries (preventing false negatives from noise terms like "how", "the", "does")
- Persisted vocabulary -- TF-IDF vocabulary persisted to
vocab_statetable, preventing vector staleness when document frequencies shift. Vectors stay valid until explicit rebuild - Pseudo-relevance feedback (PRF) -- Top results seed expansion queries for broader recall
- Concept co-occurrence -- Shared concepts across observations expand search to related topics
- Context-aware re-ranking -- Active file overlap boosts relevance (exact match + directory-level half-weight)
- Superseded detection -- Marks older observations as outdated when newer ones cover the same files with higher importance
- Adaptive time windows -- Session startup recall uses velocity-based time windows (high/medium/low activity tiers)
- Token-budgeted context -- Greedy knapsack algorithm selects session-start context within a 2,000-token budget, prioritizing by recency and importance
- Observation compression -- Old low-value observations can be compressed into weekly summaries to reduce noise
- Secret scrubbing -- Automatic redaction of API keys, tokens, PEM blocks, connection strings, and 15+ credential patterns
- Atomic writes -- All file writes (episodes, CLAUDE.md) use write-to-tmp + rename to prevent corruption on crash
- Robust locking -- PID-aware lock files with automatic stale/orphan cleanup (>30s timeout or dead PID)
- Stale session cleanup -- Sessions active for >24h are automatically marked as abandoned on next start
- Resource registry -- Indexes installed skills and agents with FTS5 search, composite scoring, and invocation tracking; searchable via
mem_registryMCP tool - Unified resource discovery -- Shared filesystem traversal layer (
resource-discovery.mjs) used by both runtime scanner and offline indexer, supporting flat directories, plugin nesting, and loose.mdfiles - Domain synonym expansion -- Registry search queries expand to domain synonyms (e.g., "fix" → debug, bugfix, troubleshoot, diagnose, repair)
- Multi-provider LLM mode -- Provider priority
ANTHROPIC_API_KEY(direct Anthropic API) →OPENROUTER_API_KEY(OpenRouter, OpenAI-compatible — point it at any model viaOPENROUTER_MODEL) →claude -pCLI fallback when no key is set - Lesson-learned indexing --
lesson_learnedfield indexed in FTS5 with weight 8, making past debugging insights directly searchable - Cross-source normalization --
mem_searchnormalizes scores across observations, sessions, and prompts before merging, preventing any source from dominating results - Exponential recency decay -- Type-differentiated half-lives (decisions: 90d, discoveries: 60d, bugfixes: 14d, changes: 7d) consistently applied in all ranking paths
- Prompt-time memory injection -- UserPromptSubmit hook automatically searches and injects relevant past observations with recency and importance weighting
- Smart skill invocation -- Auto-loaded and searched managed skills/agents include portable
~paths withRead()guidance; native plugin skills recommendSkill("full:name"); preventsSkill()misuse for managed resources that aren't registered with Claude Code's native handler - Dual injection dedup --
user-prompt-search.jsandhandleUserPromptcoordinate via temp file to prevent duplicate memory injection - Plugin cache hook self-heal -- Claude Code runtime reads plugin hooks from
~/.claude/plugins/cache/<mp>/<plugin>/<ver>/hooks/hooks.json, not from the marketplace source. Wheninstall.mjs-managedsettings.jsonhooks coexist with a stale cachehooks.json(e.g. from a previous marketplace install or a plugin auto-update), the runtime registers hooks twice → every session start / user prompt fires twice.install.mjsandhook-update.mjsnow clear cachehooks.jsonin every version dir, andhook.mjs session-startself-heals on every session (gated byhasInstallManagedHooksso plugin-only users are not affected).install.mjs statusreports cache pollution state (since v2.31.1/2.31.2). - Result-dedup cooldown -- User-prompt memory injection uses result-overlap detection (>80% ID overlap → skip) instead of time-based cooldown, allowing topic switches within seconds while preventing redundant injections
- OR query fallback -- When AND-joined FTS5 queries return zero results, automatically relaxes to OR-joined queries for broader recall (applied in both user-prompt-search and hook-memory paths)
- Configurable LLM model -- Switch between Haiku (fast/cheap) and Sonnet (deeper analysis) via
CLAUDE_MEM_MODELenv var - DB auto-recovery -- Detects and cleans corrupted WAL/SHM files on startup; periodic WAL checkpoints prevent unbounded growth
- Schema auto-migration -- Idempotent
ALTER TABLEmigrations run on every startup, safely adding new columns and indexes without data loss - Exploration bonus -- New resources in the registry get a fair chance in composite ranking; zombie resources (high recommend, zero adopt) are penalized in scoring
- LLM concurrency control -- File-based semaphore limits background workers to 2 concurrent LLM calls, preventing resource contention
- stdin overflow protection -- Hook input truncated at 256KB with regex-based action salvage for oversized tool outputs
- Cross-session handoff -- Captures session state (request, completed work, next steps, key files) on
/clearor/exit, then injects context when the next session detects continuation intent via explicit keywords or FTS5 term overlap - Git-SHA continuation anchor (v2.31.0) -- Handoff rows include
git_sha_at_handoff; any handoff matching the currentHEADcounts as continuation regardless of TTL. Code state is a stronger continuation signal than wall-clock time - Startup dashboard (v2.31.0) -- SessionStart hook aggregates
git status+~/.claude/tasks/*.json+~/.claude/plans/*.md+ most-recent exit handoff + recent event count into a single structured block injected viahookSpecificOutput.additionalContext - Activity namespace (v2.31.0) -- Dedicated
eventstable + FTS5 for non-memdir types (bugfix,lesson,bug,discovery,refactor,feature,observation,decision) that don't compete withWHAT_NOT_TO_SAVEsemantics on the observations table. CLI:claude-mem-lite activity save|search|recent|show.hook-llmroutes non-memdir summary types throughpersistHaikuSummaryso upgrades from observations→events are atomic. (v3.39: the/lessonand/bugslash commands were redirected from this events table to searchable observations —mem_searchnever read the events table, so explicit saves were unfindable; the events table remains the auto-capture activity log.) - In-place observation updates --
mem_updatetool modifies existing observations atomically (field update + FTS text rebuild + vector re-computation in one transaction), preserving original IDs and references - Bulk export --
mem_exporttool exports observations as JSON or JSONL, with project/type/date filtering and 1000-row pagination cap with batch guidance - FTS integrity management --
mem_fts_checktool verifies FTS5 index health or rebuilds indexes on demand, useful after database recovery or when search results seem wrong - Atomic multi-table writes --
saveObservationwraps observations + observation_files + observation_vectors INSERTs in a singledb.transaction(), preventing orphaned rows on crash - Modular NLP pipeline -- Synonym maps, stop words, scoring constants, and query building extracted into focused modules (
synonyms.mjs,stop-words.mjs,scoring-sql.mjs,nlp.mjs) for independent testing and maintenance - Porter-aligned PRF -- Pseudo-relevance feedback terms are now stemmed with the same Porter algorithm used by FTS5, ensuring PRF expansion terms match the search index
| Platform | Status | Notes |
|---|---|---|
| Linux | Supported | Primary development and testing platform |
| macOS | Supported | Fully compatible (Intel and Apple Silicon) |
| Windows | Not supported | Uses POSIX shell scripts (post-tool-use.sh, setup.sh) and Unix file locking; WSL2 may work but is untested |
- Node.js >= 20
- Claude Code CLI installed and configured (
claudecommand available) - SQLite3 support (provided by
better-sqlite3, compiled on install) - Platform: Linux or macOS (see Platform Support)
/plugin marketplace add sdsrss/claude-mem-lite
/plugin install claude-mem-litePlugin mode manages its own hooks/runtime. On session start it only checks and reports new claude-mem-lite versions; it does not self-overwrite plugin files in place. Update plugin-mode installs through Claude's plugin workflow.
The plugin install is complete on its own — hooks, MCP tools, and the bundled slash commands (
/mem,/lesson,/bug,/adopt) all run from the plugin with no second step. The slash commands invoke the bundled CLI by an absolute path resolved from the plugin directory (${CLAUDE_PLUGIN_ROOT}/cli.mjs <cmd>), so they work without anything on yourPATH. A globalclaude-mem-liteshell command (for running queries yourself in a terminal) is optional —npm i -g claude-mem-lite— and is a separate npm install: the plugin's auto-update does not refresh it, so re-runnpm i -g claude-mem-lite@latestif you want that shell command kept in sync. You do not need it for the plugin to be fully functional.
Auto-adopt fires on the first SessionStart per project (v2.82.1+). The plugin automatically writes the invited-memory sentinel (a system-authority pointer that boosts Claude's proactive use of
mem_recall/mem_save) into the project's memdir — no manual/adoptneeded, regardless of install path (npm, npx,/plugin, manual). Per-project opt-out:claude-mem-lite adopt --disable(--enableto re-arm). Global opt-out:export MEM_NO_AUTO_ADOPT=1. Manual/adoptremains available for re-applying after edits and for the--allbatch path.
npx github:sdsrss/claude-mem-liteSource files are automatically copied to ~/.claude-mem-lite/ for persistence.
Note:
npx github:…installs from the repo's default branch (HEAD), which can be ahead of the latest published release. For the stable released version use the npm package (npx claude-mem-lite), or pin a release tag:npx github:sdsrss/claude-mem-lite#vX.Y.Z.
git clone https://github.com/sdsrss/claude-mem-lite.git
cd claude-mem-lite
node install.mjs installSource files stay in the cloned repo. Update via git pull && node install.mjs install.
- Install dependencies --
npm install --omit=dev(compiles nativebetter-sqlite3) - Register MCP server --
mem-liteserver with 20 tools (9 core exposed viatools/list+ 11 hidden-but-callable; see the Usage section for the full table). The pre-v2.78 generic server namememis renamed tomem-litefor namespace hygiene; the tool names themselves (mem_search,mem_recall, ...) are unchanged. - Configure hooks --
PostToolUse,SessionStart,Stop,UserPromptSubmitlifecycle hooks - Create data directory --
~/.claude-mem-lite/(hidden) for database, runtime, and managed resource files - Auto-migrate -- If
~/.claude-mem/(original claude-mem) or~/claude-mem-lite/(pre-v0.5 unhidden) exists, migrates database and runtime files to~/.claude-mem-lite/, preserving the original untouched - Initialize database -- SQLite with WAL mode, FTS5 indexes created on first server start
Restart Claude Code after installation to activate.
All installation methods auto-detect and migrate from previous versions:
From claude-mem (original ~/.claude-mem/):
- Copy
claude-mem.db→~/.claude-mem-lite/claude-mem-lite.db(renamed) - Copy the
runtime/directory - Original
~/.claude-mem/is preserved (no deletion, no overwrite)
From pre-v0.5 unhidden directory (~/claude-mem-lite/):
- Entire directory is moved to
~/.claude-mem-lite/(hidden)
In-place rename:
- Existing
claude-mem.dbin~/.claude-mem-lite/is automatically renamed toclaude-mem-lite.db
Remove old directories manually after confirming:
rm -rf ~/.claude-mem/ # original claude-mem
rm -rf ~/claude-mem-lite/ # pre-v0.5 unhidden (if not auto-moved)~/.claude-mem-lite/
claude-mem-lite.db # SQLite database — memory (WAL mode)
resource-registry.db # SQLite database — skill/agent registry
runtime/
session-<project> # Active session state
ep-<project>.json # Episode buffer
ep-flush-*.json # Flushed episodes awaiting processing
reads-<project>.txt # Read file paths (collected on flush)
managed/
skills/ # Standalone skills: {name}/SKILL.md
agents/ # Agent plugins: {group}/agents/{name}.md + skills/*/SKILL.md
repos/ # Shallow-cloned source repos
As of v2.70.0, the server registers 20 tools in total but only the 9 core
tools appear in tools/list. The 11 hidden tools remain callable at the
protocol layer (tools/call by exact name still routes normally); they're
omitted from the list response so Claude Code sessions don't load 11 extra
tool schemas at startup. Hidden tools are the maintenance / admin / browser
surface — reach them through the CLI column in the second table.
Core (9, exposed to Claude Code)
| Tool | Description |
|---|---|
mem_search |
FTS5 full-text search with BM25 ranking. Filters by type, project, date range, importance level. |
mem_recent |
Show most recent observations, ordered by time. Quick snapshot of latest activity. |
mem_recall |
Recall observations related to a file. Use before editing to surface past bugfixes and context. |
mem_timeline |
Browse observations chronologically around an anchor point. |
mem_get |
Retrieve full details for specific observation IDs (includes importance and related_ids). |
mem_save |
Manually save a memory/observation. Accepts closes_deferred array for transactional closure of deferred work. |
mem_defer |
Mark work for a future session (v2.70+). First-class carry-forward signal, surfaced in SessionStart ### Deferred Work block. |
mem_defer_list |
List open deferred items for the current project. |
mem_defer_drop |
Drop a deferred item without fixing it; requires a reason for the audit trail. |
Hidden-but-callable (11, CLI-routed)
| Tool | CLI equivalent | Notes |
|---|---|---|
mem_update |
claude-mem-lite update <id> |
Edit an observation in place. |
mem_stats |
claude-mem-lite stats |
Counts, type distribution, daily activity. |
mem_delete |
claude-mem-lite delete <id> |
Preview / confirm workflow, FTS5 cleanup. |
mem_compress |
claude-mem-lite compress |
Roll up old low-value observations (preview default; --execute to apply). |
mem_maintain |
claude-mem-lite maintain scan --ops dedup,decay |
dedup / decay / cleanup / rebuild_vectors (scan previews, execute applies). |
mem_optimize |
claude-mem-lite optimize |
LLM-powered re-enrich / normalize / cluster-merge (preview default; --run to apply). |
mem_export |
claude-mem-lite export |
JSON / JSONL dump, filters by project, type, date. |
mem_fts_check |
claude-mem-lite fts-check <check|rebuild> |
FTS5 integrity + rebuild. |
mem_browse |
claude-mem-lite browse |
Tier-grouped dashboard (working / active / archive). |
mem_registry |
claude-mem-lite registry <action> |
List / search / import / remove skills + agents. |
mem_use |
MCP only | Load a skill / agent from the registry by name. |
/mem search <query> # Full-text search across all memories
/mem recent [n] # Show recent N observations (default 10)
/mem recall <file> # Show past observations for a file
/mem save <text> # Save a manual memory/note
/mem stats # Show memory statistics
/mem timeline <query> # Browse timeline around a match
/mem browse # Tier-grouped memory dashboard
/mem <query> # Shorthand for search
/lesson <text> # Save a non-obvious lesson to the events table (v2.31.0)
/bug <text> # Log a known bug + repro steps to the events table (v2.31.0)
1. mem_search(query="auth bug") -> compact ID index
2. mem_timeline(anchor=12345) -> surrounding context
3. mem_get(ids=[12345, 12346]) -> full details
Opt-in mechanism that installs a slug-scoped managed block into the project's
own CLAUDE.md (plus an on-demand detail doc under .claude/) so Claude Code
loads the plugin's MCP-tool triggers as project instructions — a higher
instruction-following authority than MCP server instructions (which are framed
as tool metadata). Claude Code loads CLAUDE.md and the memdir MEMORY.md at
equal weight, so steering lives in CLAUDE.md (the canonical home for project
instructions) rather than polluting MEMORY.md, which is reserved for the user's
own memories. The pre-v3.13 scheme wrote into MEMORY.md; it is migrated away
automatically on the next SessionStart.
claude-mem-lite adopt # install for current project
claude-mem-lite adopt --all # install for every project under ~/.claude/projects/
claude-mem-lite adopt --status # list adopted/disabled projects + current gating snapshot
claude-mem-lite adopt --dry-run # preview without writing
claude-mem-lite adopt --disable # opt out of auto-adopt for current project (writes .mem-no-auto-adopt sentinel)
claude-mem-lite adopt --enable # re-arm auto-adopt for current project (deletes the sentinel)
claude-mem-lite unadopt # remove sentinel + doc (runtime marker stays to honor the explicit removal)Slash commands /adopt and /unadopt wrap the same CLI.
What adoption changes:
- A
<!-- claude-mem-lite:begin v1 -->…<!-- claude-mem-lite:end -->managed block is added to<cwd>/CLAUDE.mdunder its own## claude-mem-lite — persistent memoryheader, containing a compact trigger table pointing atmem_recall/mem_save/mem_deferwith their key arguments. The block is slug-scoped: only this region is managed; the rest of yourCLAUDE.mdis preserved verbatim, and it coexists with other plugins' blocks (e.g.code-graph-mcp) in the same file. - A
<cwd>/.claude/plugin_claude_mem_lite.mddetail file is written (not auto-loaded; read on demand when theCLAUDE.mdblock points to it). The block auto-refreshes when the shipped content drifts (version bump or template change), unlessCLAUDE_MEM_NO_TEMPLATE_REFRESH=1. - Post-adopt the conservative hook layer auto-trims: MCP server instructions
drop the
WHEN TO USEsection, SessionStart injection drops theFile Lessons/Key Contextsections.#IDreferences and theRecenttable still fire somem_getremains reachable.
When does it take effect?
- The
CLAUDE.mdmanaged block and the hook-layer trim (File Lessons/Key Context/ lesson suffix) apply on the next SessionStart (any new Claude Code session in the adopted project). - The MCP server instructions are built once at server boot and MCP has no
"push" protocol — the
WHEN TO USE/Decision rulestrim only applies after Claude Code restarts and re-spawns the mem-lite MCP server. A single/exit+ fresh session is enough. Same caveat applies tounadopt.
Safety:
- Hash-guarded: editing the managed-block body yourself blocks automatic
rewrites unless you pass
--force. - Slug-scoped & dedup-guarded: only the
claude-mem-lite:begin…endregion is ever rewritten, and duplicate / CRLF-orphaned copies are collapsed to one. Unlike the legacyMEMORY.mdscheme there is no line-budget gate —CLAUDE.mdhas no truncation cap. - Auto-adopt fires on the first SessionStart per project for any install
path (v2.82.1+). Per-project opt-out:
claude-mem-lite adopt --disable(writes a durable<memdir>/.mem-no-auto-adoptsentinel that survives marker deletion / plugin reinstalls). Global opt-out:MEM_NO_AUTO_ADOPT=1. Pre-v2.82.1 theCLAUDE_PLUGIN_ROOTgate left auto-adopt unreachable for everyinstall.mjs-written hook (the common path) — see CHANGELOG v2.82.1. - The fallback hook layer is never removed from source — conditional trim is runtime-gated on sentinel presence, so projects without adoption get the full verbose output.
See docs/plans/2026-04-16-invited-memory-pattern.md for the full design
(including the reusable template other plugins can follow).
Five core tables with FTS5 virtual tables for search:
observations -- Individual coding observations (decisions, bugfixes, features, etc.)
id, memory_session_id, project, type, title, subtitle,
text, narrative, concepts, facts, files_read, files_modified,
importance, related_ids, created_at, created_at_epoch,
lesson_learned, minhash_sig, access_count, compressed_into, search_aliases,
branch, superseded_at, superseded_by, last_accessed_at
session_summaries -- LLM-generated session summaries
id, memory_session_id, project, request, investigated,
learned, completed, next_steps, files_read, files_edited, notes,
remaining_items, lessons, key_decisions
sdk_sessions -- Session tracking
id, content_session_id, memory_session_id, project,
started_at, completed_at, status, prompt_counter
user_prompts -- User prompts captured via UserPromptSubmit hook
id, content_session_id, prompt_text, prompt_number
session_handoffs -- Cross-session handoff snapshots (UPSERT, max 2 per project)
project, type, session_id, working_on, completed, unfinished,
key_files, key_decisions, match_keywords, created_at_epoch
observation_files -- Normalized file membership for efficient file-based recall
obs_id, filename
observation_vectors -- TF-IDF vector embeddings for hybrid search
observation_id, vector (BLOB Float32Array), vocab_version, created_at_epoch
vocab_state -- Persisted TF-IDF vocabulary for stable vector indexing
term, term_index, idf, version, created_at_epoch
FTS5 indexes: observations_fts (title, subtitle, narrative, text, facts, concepts, lesson_learned), session_summaries_fts, user_prompts_fts
SessionStart
-> Generate session ID (or save handoff snapshot on /clear)
-> Mark stale sessions (>24h active) as abandoned
-> Clean orphaned/stale lock files
-> Query recent observations (24h)
-> Inject context into CLAUDE.md + stdout
PostToolUse (every tool execution)
-> Bash pre-filter skips noise in ~5ms (Read paths tracked to reads file)
-> Detect Bash significance (errors, tests, builds, git, deploys)
-> Accumulate into episode buffer
-> Proactive file history: show past observations for edited files
-> Flush when: buffer full (10 entries) | 5min gap | context change
-> Collect Read file paths into episode on flush
-> Spawn LLM episode worker for significant episodes
-> Error-triggered recall: search memory for related past fixes
UserPromptSubmit (two parallel paths)
-> [user-prompt-search.js] Auto-search memory via FTS5 + active file context
-> [user-prompt-search.js] Inject relevant past observations with recency/importance weighting
-> [user-prompt-search.js] Write injected IDs to temp file for dedup
-> [user-prompt-search.js] L1 skill auto-load: match managed skill names in prompt
-> Load content with portable ~ path + Read() guidance
-> source="managed-skill|managed-agent", path="~/.claude-mem-lite/managed/..."
-> [hook.mjs handleUserPrompt] Capture user prompt text to user_prompts table
-> [hook.mjs handleUserPrompt] Increment session prompt counter
-> [hook.mjs handleUserPrompt] Handoff: detect continuation intent → inject previous session context
-> [hook.mjs handleUserPrompt] Semantic memory injection (hook-memory.mjs), deduped via temp file
Stop
-> Flush final episode buffer
-> Save handoff snapshot (on /exit)
-> Mark session completed
-> Spawn LLM summary worker (poll-based wait)
The resource registry (registry.mjs, registry-retriever.mjs) indexes installed skills and agents into a searchable FTS5 database. Unlike the previous proactive dispatch system, the registry is now on-demand — it's reachable via the claude-mem-lite registry CLI (primary path for Claude Code since v2.34.0 hides the mem_registry MCP tool from tools/list) or by direct tools/call mem_registry for MCP clients that know the name.
Registry pipeline:
-> registry-scanner.mjs discovers skills/agents on filesystem
-> resource-discovery.mjs handles flat dirs, plugin nesting, loose .md files
-> registry-indexer.mjs indexes content into FTS5 with metadata
-> registry-retriever.mjs provides BM25-ranked search with synonym expansion
-> mem_registry MCP tool exposes search/list/stats/import/remove/reindex actions
Smart invocation (three layers):
L1 auto-load: UserPromptSubmit matches managed skill name in prompt
-> Loads content with path="~/.claude-mem-lite/managed/.../SKILL.md"
-> Guides: Read("path") or mem_use(name="..."), never Skill()
L2 bridge: PreToolUse hook intercepts Skill("name") for managed resources
-> Outputs content, prevents native handler failure
L3 explicit: mem_use(name="...") loads full content with reload path
Search: managed resources → Read(path), native plugins → Skill("full:name")
Composite scoring for search results: BM25 relevance (40%) + repo stars (15%) + success rate (15%) + adoption rate (10%) + freshness (10%) + exploration bonus (10%). Domain filtering ensures platform-specific resources (iOS, Go, Rust) only surface for matching projects.
Episodes are batched related operations (edits to the same file group) that get processed by a background LLM worker:
Episode buffer -> Flush to JSON -> claude -p --model haiku -> Structured observation -> SQLite
Each observation includes type, title, narrative, concepts, facts, importance (1-3), and is automatically deduplicated via two tiers: Jaccard similarity (>70% within 5 minutes) and MinHash signatures (>80% within 7 days across sessions). If the LLM call fails, a degraded observation is saved with inferred metadata (zero data loss). Related observations are linked via related_ids based on FTS5 title similarity and file overlap.
# Plugin install:
/plugin install claude-mem-lite # Install / update
/plugin uninstall claude-mem-lite # Uninstall
# git clone install:
node install.mjs install # Install and configure
node install.mjs uninstall # Remove (keep data)
node install.mjs uninstall --purge # Remove and delete all data
node install.mjs status # Show current status
node install.mjs doctor # Diagnose issues
node install.mjs cleanup-hooks # Remove only stale claude-mem-lite hooks from settings.json
node install.mjs update # Force-check for updates and install them (direct install / npx mode)
# npx install:
npx claude-mem-lite # Install / reinstall
npx claude-mem-lite uninstall # Remove (keep data)
npx claude-mem-lite doctor # Diagnose issuesNotes:
- Plugin mode only reports available updates; it does not self-update plugin files.
To upgrade an installed plugin to the latest published version, run inside Claude Code:
(The first command refreshes the local marketplace clone; the second reinstalls from it. Without the first command,
/plugin marketplace update sdsrss /plugin install claude-mem-lite@sdsrss/plugin installreuses the stale local clone and you stay on whichever version you originally pulled.) - Direct install / npx mode keeps auto-update enabled and uses staged replacement with rollback on install failure.
- If you disabled the plugin but still have old mem hooks in
~/.claude/settings.json, runnode install.mjs cleanup-hooks.
Checks Node.js version, dependencies, server/hook files, database integrity, FTS5 indexes, and stale processes.
Shows MCP registration, hook configuration, plugin disabled state, and database stats (observation/session counts).
If you see ERR_MODULE_NOT_FOUND on PreToolUse:Read/Edit/Skill hooks, or claude-mem-lite commands crash with import errors, you're likely hit by a partial auto-update — the updater copied new scripts but missed a sibling lib/* file, breaking the hook chain (and the next auto-update that would have healed it).
v2.84.0+ ships a repair subcommand that re-syncs from the latest GitHub release:
claude-mem-lite repairIf repair itself fails (the bin is older than v2.84.0, or the bin is also broken), run this one-liner — it pulls a fresh tarball into a temp dir and runs that tarball's install.mjs, bypassing every file on your disk:
T=$(mktemp -d) && curl -sL https://api.github.com/repos/sdsrss/claude-mem-lite/tarball | tar xz -C "$T" --strip-components=1 && node "$T/install.mjs" installAfter it finishes, ~/.claude-mem-lite/ is back in sync with the latest release and claude-mem-lite repair is available for next time.
# Plugin:
/plugin uninstall claude-mem-lite
# git clone:
cd claude-mem-lite
node install.mjs uninstall # Keeps ~/.claude-mem-lite/ data
node install.mjs uninstall --purge # Deletes ~/.claude-mem-lite/ and all data
# npx:
npx claude-mem-lite uninstall
npx claude-mem-lite uninstall --purgeData in ~/.claude-mem-lite/ is preserved by default. Delete manually if needed:
rm -rf ~/.claude-mem-lite//plugin uninstall only removes the plugin manifest — it does not touch ~/.claude/settings.json. If you've ever run claude-mem-lite install (npx or git-clone path), hook entries pointing at ~/.claude-mem-lite/hook.mjs were written into your user-global settings, and they keep firing after /plugin uninstall. If ~/.claude-mem-lite/hook.mjs still exists they double-fire alongside the plugin; if you also ran rm -rf ~/.claude-mem-lite/ they error every session.
The safe sequence is: run claude-mem-lite uninstall first (which cleans the settings.json hooks plus the global MCP registration), then /plugin uninstall claude-mem-lite, then optionally rm -rf ~/.claude-mem-lite/.
If you already uninstalled in the wrong order, claude-mem-lite doctor flags orphan hooks under Orphan hooks: with the exact cleanup command.
claude-mem-lite/
.claude-plugin/
plugin.json # Plugin manifest
marketplace.json # Marketplace catalog
.mcp.json # MCP server definition (plugin root)
hooks/
hooks.json # Hook definitions (plugin mode)
commands/
mem.md # /mem command definition
server.mjs # MCP server: tool definitions, FTS5 search, database init
search-scoring.mjs # Extracted search helpers: re-ranking, PRF, concept expansion
hook.mjs # Claude Code hooks: episode capture, error recall, session management
hook-llm.mjs # Background LLM workers: episode extraction, session summaries
hook-shared.mjs # Shared hook infrastructure: session management, DB access, LLM calls
hook-handoff.mjs # Cross-session handoff: state extraction, intent detection, injection
hook-context.mjs # CLAUDE.md context injection and token budgeting
hook-episode.mjs # Episode buffer management: atomic writes, pending entry merging
hook-memory.mjs # Semantic memory injection on user prompt
hook-semaphore.mjs # LLM concurrency control: file-based semaphore for background workers
schema.mjs # Database schema: single source of truth for tables, migrations, FTS5
tool-schemas.mjs # Shared Zod schemas for MCP tool validation
tfidf.mjs # TF-IDF vector engine: tokenization, vocabulary building, vector computation, cosine similarity, RRF merge
tier.mjs # Temporal tier system: activity-based time window classification
utils.mjs # Re-export hub: backward-compatible surface for all utility modules
nlp.mjs # FTS5 query building: synonym expansion, CJK bigrams, sanitization
scoring-sql.mjs # BM25 weight constants and type-differentiated decay half-lives
stop-words.mjs # Shared base stop-word set for all NLP/search modules
synonyms.mjs # Unified synonym source: SYNONYM_MAP (bidirectional) + DISPATCH_SYNONYMS
project-utils.mjs # Shared project name resolution with in-process cache
secret-scrub.mjs # API key, token, PEM, and credential pattern redaction
format-utils.mjs # String formatting: truncate, typeIcon, date/time/week formatting
hash-utils.mjs # MinHash signatures, Jaccard similarity for dedup
bash-utils.mjs # Bash output significance detection: errors, tests, builds, deploys
# Resource registry
registry.mjs # Resource registry DB: schema, CRUD, FTS5, invocation tracking
registry-retriever.mjs # FTS5 retrieval with synonym expansion and composite scoring
registry-indexer.mjs # Resource indexing pipeline
registry-scanner.mjs # Filesystem scanner: reads content + hashes, delegates discovery
resource-discovery.mjs # Shared discovery layer: flat dirs, plugin nesting, loose .md files
haiku-client.mjs # Unified Haiku LLM wrapper: direct API or CLI fallback
# Install & config
install.mjs # CLI installer: setup, uninstall, status, doctor (npx/git clone mode)
skill.md # MCP skill definition (npx/git clone mode)
package.json # Dependencies and metadata
scripts/
setup.sh # Setup hook: npm install + migration (hidden dir + old dir)
post-tool-use.sh # Bash pre-filter: skips noise in ~5ms, tracks Read paths
user-prompt-search.js # UserPromptSubmit hook: auto-search memory + L1 skill auto-load
pre-skill-bridge.js # PreToolUse hook: L2 skill bridge for managed resources
pre-tool-recall.js # PreToolUse hook: file lesson recall before Edit/Write
prompt-search-utils.mjs # Shared logic: skip patterns, intent detection, name matching
convert-commands.mjs # Converts command .md → SKILL.md in managed plugins
index-managed.mjs # Offline indexer for managed resources
# Test & benchmark (dev only)
tests/ # Unit, property, integration, contract, E2E, pipeline tests
benchmark/ # BM25 search quality benchmarks + CI gate
Benchmarked on 200 observations across 30 queries (standard + hard-negative categories),
measuring the production-hybrid retriever (FTS5 BM25 + TF-IDF vector + RRF) — the path
mem_search / recall actually use. The CI gate (npm run benchmark:gate) runs this same
path and fails on regression.
| Metric | Score (production-hybrid) |
|---|---|
| Recall@10 | 0.90 |
| Precision@10 | 0.79 |
| nDCG@10 | 0.97 |
| MRR@10 | 0.97 |
| P95 search latency | ~3ms |
Note on the path measured. Earlier versions of this table reported the lexical FTS-only path (Precision@10 0.96, P95 0.15ms). The hybrid vector arm trades raw precision@10 for higher recall / nDCG / MRR by surfacing semantically-related candidates beyond exact lexical matches; the gate now measures the hybrid path so these numbers reflect real
mem_searchbehavior. For field-comparable recall, see the LongMemEval section below.
Beyond the in-repo micro-benchmark above, claude-mem-lite is measured on
LongMemEval (Wu et al.) — a
500-question long-term-memory benchmark — so its recall is comparable to the
field, not just to itself. Metric is recall_any@k: does any gold evidence session appear in the
top k retrieved? This is the same session-level definition the systems we
compare against report on this split — agentmemory
(BM25 + vector + graph) and dense-embedding systems like MemPalace — so the rows
below sit on one axis, not metric-shopped. (Note: 65% of the 500 questions have
multiple gold sessions, so recall_any@k is looser than fractional recall there;
all systems in this comparison report the any-hit form.) Corpus is user-turns-only
(the standard raw-baseline rule). Runners: benchmark/longmemeval.mjs (lexical)
and benchmark/longmemeval-rerank.mjs (rerank).
| Retriever (zero embeddings) | @1 | @5 | @10 |
|---|---|---|---|
| Lexical hybrid — FTS5 + TF-IDF + RRF | 83.4% | 95.2% | 96.0% |
| + one top-20 LLM rerank pass † | 92.8% | 96.8% | 97.4% |
n = 500 questions. The lexical row was re-measured 2026-07-18: the v3.39–v3.45 alias/synonym-pipeline work lifted it from the previously published 76.8/90.6/95.2 on the same harness and dataset (both unchanged since that run — the gain is engine-side, not metric drift). † The rerank row is the 2026-06 measurement taken against the older lexical baseline; with lexical now at 95.2 @5 its remaining headroom is ~1.6pt and a re-measurement is pending. The rerank pass hands the top 20 lexical candidates to a single Haiku call (~1.4 s/query) that reorders them; it is never worse than the lexical baseline by construction — any LLM or parse failure falls back to the original candidate order.
Stricter metric, for the record. The rows above are recall_any@k — does any
gold session reach the top k — the metric agentmemory and MemPalace publish, so the
comparison is like-for-like. Under the stricter standard recall@k (|gold ∩ top-k| / |gold|, the fraction of all gold sessions retrieved), the lexical stack scores
@1 = 52.9% / @5 = 87.8% / @10 = 91.0%. The whole gap is the 65% of questions with
multiple gold sessions — any-hit needs one, fractional needs them all, and @1 is capped
at 1/|gold| there; single-gold question types score identically under both.
benchmark/longmemeval.mjs reports both columns (the rerank row's fractional is not yet
measured).
On embeddings, honestly. With no LLM in the loop, our zero-embedding lexical stack now ties the BM25 + vector + graph hybrid (agentmemory, 95.2% @5) at the same retrieval stage; a dense-embedding baseline (MemPalace, ~96.6% @5) still leads by ~1.4pt. The remaining gap concentrates in paraphrase (single-session-preference is our lowest category at 80.0% @5). The rerank row's point stands: a single cheap LLM call reorders the top-20 lexical candidates because the candidate set is already rich enough that ranking, not recall, is the bottleneck. An embedding-plus-rerank stack still leads when both sides spend an LLM call; the takeaway is that claude-mem-lite reaches embedding-competitive recall with no vector model, no knowledge graph, no Python, and no external service.
Per-category any@5, lexical (2026-07-18 run): knowledge-update 100.0 · single-session-user 100.0 · multi-session 94.7 · single-session-assistant 94.6 · temporal-reasoning 94.0 · single-session-preference 80.0.
npm run lint # ESLint static analysis
npm test # Run full test suite (vitest)
npm run test:smoke # Run 5 core smoke tests
npm run test:coverage # Run tests with V8 coverage (≥75% lines/functions, ≥65% branches)
npm run benchmark # Run full search quality benchmark
npm run benchmark:gate # CI gate: fails if metrics regress beyond 5% tolerance| Variable | Description | Default |
|---|---|---|
CLAUDE_MEM_DIR |
Custom data directory. All databases, runtime files, and managed resources are stored here. | ~/.claude-mem-lite/ |
CLAUDE_MEM_MODEL |
LLM model for background calls (episode extraction, session summaries). Accepts haiku or sonnet. |
haiku |
ANTHROPIC_API_KEY |
Anthropic API key. When set, all background LLM calls go directly to the Anthropic Messages API (with prompt caching). Highest priority. | (unset → CLI) |
OPENROUTER_API_KEY |
OpenRouter API key (OpenAI-compatible). Used for background LLM calls when ANTHROPIC_API_KEY is not set. If neither key is set, calls fall back to the claude -p CLI. |
(unset) |
OPENROUTER_MODEL |
Overrides the OpenRouter model slug for all background calls (e.g. openai/gpt-4o-mini, qwen/qwen-2.5-72b-instruct). When unset, the CLAUDE_MEM_MODEL tier maps to anthropic/claude-haiku-4.5 (haiku) or anthropic/claude-sonnet-4.5 (sonnet). |
(tier default) |
CLAUDE_MEM_DEBUG |
Enable debug logging (1 to enable). |
(disabled) |
MEM_QUIET_HOOKS |
Low-noise hooks. 1 drops the File Lessons / Key Context sections from SessionStart injection, the lesson suffix from [mem] Related memories, and the WHEN TO USE / Decision rules blocks from MCP server instructions. IDs and the Recent table still surface so mem_get(ids=[…]) remains reachable. Intended for users running the invited-memory adopt path or who otherwise want minimal auto-injection. Since v2.82.0 this env no longer gates auto-adopt — use MEM_NO_AUTO_ADOPT=1 for that. |
(disabled) |
MEM_NO_AUTO_ADOPT |
Global opt-out for auto-adopt (v2.82.0+). 1 prevents the first-SessionStart auto-write of the invited-memory sentinel across all projects. For per-project opt-out use claude-mem-lite adopt --disable instead (writes a durable <memdir>/.mem-no-auto-adopt sentinel that survives marker deletion). |
(disabled) |
MEM_NO_ADOPT_HINT |
Silences the one-line "Invited-memory 未启用:claude-mem-lite adopt…" hint that SessionStart appends when the current project hasn't been adopted. Since v2.82.1 auto-adopt fires on first SessionStart for any install path, so this hint typically surfaces only when you've explicitly opted out (MEM_NO_AUTO_ADOPT=1 or claude-mem-lite adopt --disable). |
(disabled) |
A memory system lets Claude Code remember context — coding decisions, bug fixes, file history — across sessions. By default Claude Code's context resets each session; claude-mem-lite persists observations to a local SQLite database and re-injects them at session start and on relevant prompts.
No. Claude Code's CLAUDE.md and MEMORY.md files act as static instruction memory, but there is no native dynamic recall of past sessions, bug fixes, or decisions. claude-mem-lite adds that layer via MCP and hooks, with no manual note-taking required.
mem0 and the MCP memory server are general-purpose LLM memory frameworks designed for any client. claude-mem-lite is purpose-built for Claude Code's hook lifecycle: it captures episodes (batched tool calls), uses domain-specific synonym expansion for code terms (K8s, DB, 数据库, ...), and surfaces past observations proactively before file edits via the PreToolUse:Edit hook.
The original called an LLM on every tool use with raw JSON inputs. claude-mem-lite batches 5–10 operations per LLM call, uses a smaller model (Haiku), and runs a deterministic code-level filter before sending anything to the model. Net result: an estimated ~600× lower cost (an architecture estimate from the cost model above, not a measured benchmark) with equivalent search quality. See the Architecture comparison above.
Project-scoped by default — each project has its own memory namespace. Single-machine only (SQLite, not networked). Use mem_export (JSON / JSONL) to back up or migrate between machines.
Only the Haiku summarization step calls Anthropic's API (or the local claude -p CLI if no API key is set). All search, storage, and retrieval is local SQLite — no telemetry, no third-party services.
Claude Code 怎么跨会话记住内容? 默认不能。claude-mem-lite 通过 MCP 协议和钩子自动把决策、bug 修复、文件历史持久化到本地 SQLite,下次会话开始时再注入。
和 mem0、官方 MCP memory server 有什么区别? 那两个是通用 LLM 记忆框架;claude-mem-lite 是为 Claude Code 钩子生命周期定制的:批量 episode 处理、代码领域同义词扩展(K8s/DB/数据库等)、文件编辑前主动召回相关历史。
支持中文吗? 完整支持。FTS5 + 中英文同义词扩展(100+ 对,含 CJK ↔ EN 跨语言映射),中文记忆也可用英文关键词召回,反之亦然。
MIT