# remem: Persistent Memory for Claude Code and OpenAI Codex
> Open-source agent memory for Claude Code, OpenAI Codex, MCP, and long-running engineering work.
`remem` is a single Rust binary that automatically captures, distills, and injects project context across Claude Code and OpenAI Codex sessions: decisions, patterns, preferences, and learnings. Stop re-explaining your project every new coding-agent session.
[](https://github.com/majiayu000/remem/actions/workflows/ci.yml)
[](LICENSE)
## The Problem
- **Session amnesia**: every new Claude Code or Codex session starts from zero.
- **Lost context**: bug-fix rationale and design decisions disappear after the session ends.
- **Preference fatigue**: the same preferences must be repeated every session.
- **No continuity**: long-running work is hard to resume with confidence.
## How remem Solves This
| "We use FTS5 trigram tokenizer..." (every session) | Injected automatically from memory |
| "Do not use `expect()` in non-test code" (again) | Preference surfaced before you ask |
| "Last session we decided to..." (reconstruct manually) | Decision history with rationale |
| Bug context lost after session ends | Root cause + fix preserved |
## Quickstart
```bash
brew install majiayu000/tap/remem
remem install --target codex
remem status
```
If you do not use Homebrew:
```bash
~/.local/bin/remem status
```
`remem install --target codex` creates or updates:
- `~/.remem/.key` and the encrypted `~/.remem/remem.db`
- `~/.remem/config.toml` memory-AI profiles
- Codex MCP registration in `~/.codex/config.toml`
- Codex SessionStart/Stop hooks in `~/.codex/hooks.json`
Success looks like:
- `remem install` prints `key`, `db`, `config`, `MCP`, `hooks`, and `binary`
lines.
- `remem status` prints database counts instead of an error.
Restart Codex after installation and finish one session. Then run `remem doctor`.
For a Codex-only setup, it reports Schema, Key format, Database, and the Codex
Hooks/MCP rows as ok. If Claude Code config directories already exist, Claude
rows can warn until you also run `remem install --target claude` or
`remem install --target all`. If it warns about multiple `remem` binaries,
follow the printed install-path fix so hooks keep using the intended binary.
For Claude Code, use `remem install --target claude`; to configure both hosts,
use `remem install --target all`.
## Other Install Channels
```bash
# Quick install options
# npm wrapper
npm install -g @remem-ai/remem
remem install --target codex
# Cargo
cargo install remem-ai --bin remem
remem install --target codex
# Manual GitHub Release download
curl -LO https://github.com/majiayu000/remem/releases/latest/download/remem-darwin-arm64.tar.gz
tar xzf remem-darwin-arm64.tar.gz
mv remem ~/.local/bin/
codesign -s - -f ~/.local/bin/remem # required on macOS ARM
remem install --target codex
# Build from source
git clone https://github.com/majiayu000/remem.git
cd remem
cargo build --release
cp target/release/remem ~/.local/bin/
codesign -s - -f ~/.local/bin/remem # required on macOS ARM
remem install --target codex
```
Use one canonical `remem` command on PATH. Standalone and source installs
should normally live at `~/.local/bin/remem`; Windows standalone installs
should use `%USERPROFILE%\.local\bin\remem.exe`. If you install through a
package manager such as Homebrew or Cargo, update through that same channel
and avoid keeping a second manual copy earlier or later on PATH. `remem doctor`
and `remem install --dry-run` warn when multiple `remem` executables are
visible.
### Updating an Existing Install
When you replace the binary manually, rerun `remem install` so existing Claude Code
and Codex hook commands pick up the current host-aware settings:
```bash
cargo build --release
cp target/release/remem ~/.local/bin/
codesign -s - -f ~/.local/bin/remem # required on macOS ARM
remem install --target all
```
Verify the installed hooks include host-specific context commands:
```bash
jq -r '.hooks.SessionStart[]?.hooks[]?.command' ~/.claude/settings.json
jq -r '.hooks.SessionStart[]?.hooks[]?.command' ~/.codex/hooks.json
```
Expected commands are host-only; model, executor, and context policy live in
`~/.remem/config.toml`:
```text
/Users/you/.local/bin/remem context --host claude-code
/Users/you/.local/bin/remem context --host codex-cli
```
## Use With Codex
`remem install --target codex` configures Codex in four ways:
- Enables Codex hooks with `[features].hooks = true` in `~/.codex/config.toml`
- Registers `remem` as an MCP server in `~/.codex/config.toml`
- Writes Codex hook commands to `~/.codex/hooks.json`
- Creates or updates `~/.remem/config.toml` memory-AI profiles
After restarting Codex, remem automatically injects relevant project memory at
session start and summarizes the session at stop. Codex can also call the MCP
tools exposed by `remem mcp`, including `search`, `get_observations`,
`save_memory`, `workstreams`, and `timeline`.
The default Codex integration is intentionally low-noise: it uses
`SessionStart` for context injection and `Stop` for background summarization.
Codex uses strict duplicate-injection gating via
`[memory_ai.hosts."codex-cli"].context_gate = "strict"`, so a mid-chat
`SessionStart` repeat stays silent after the first injection for the same
session. It does not install high-frequency Bash observation by default.
### Codex Plugin
This repository includes a local Codex plugin wrapper in `plugins/remem`.
The plugin exposes `remem mcp` and a Remem skill while keeping hook activation
explicit. The complete product direction is documented in
[`docs/spec-codex-plugin-complete-design.md`](docs/spec-codex-plugin-complete-design.md);
the current plugin is the local development foundation, not the final
self-contained plugin experience. To try it from a local checkout:
```bash
codex plugin marketplace add .
codex plugin add remem@remem-local
```
After installing the plugin, start a new Codex thread. To enable automatic
SessionStart context injection and Stop summarization, run:
```bash
cargo build --release
node plugins/remem/scripts/activate-codex.js --dry-run
node plugins/remem/scripts/activate-codex.js
```
## Distribution Channels
Currently published:
- Homebrew: `brew install majiayu000/tap/remem`
- GitHub Releases: prebuilt binaries for macOS and Linux on x64/arm64
- crates.io: `cargo install remem-ai --bin remem`
- npm: `npm install -g @remem-ai/remem`
- Source build: `cargo build --release`
Good next channels:
- apt/yum packages: useful later, after the binary install path and service
story are stable across Linux distributions
## How It Works
remem uses host-specific hook strategies:
```
Claude Code workflow
|
|- SessionStart -> Inject memories + preferences
|- UserPromptSubmit -> Register session, flush stale queues
|- PostToolUse -> Capture tool operations (queued, <1ms)
'- Stop -> Summarize in background (~6ms return)
Codex workflow
|
|- SessionStart -> Inject memories + preferences
'- Stop -> Summarize in background with Codex CLI
```
Codex does not install a high-frequency `PostToolUse(Bash)` observe hook by
default. Shell-heavy sessions must use the coalesced capture pipeline before
per-command capture is enabled again; otherwise Bash output can create an
unbounded backlog. Existing legacy hooks are also ignored unless
`REMEM_ENABLE_CODEX_BASH_OBSERVE=1` is set explicitly.
The capture pipeline starts with an append-only ledger:
`captured_events` stores raw hook/session evidence, `event_blobs` keeps large
payloads out of prompt-sized rows, and `extraction_tasks` coalesces work by
host/project/session instead of creating one LLM job per tool call. Curated
memory remains the promoted output of this pipeline, not the raw event itself.
## Remem vs Built-in `MEMORY.md`
Built-in memory files are enough when the context is small, stable, and worth
editing by hand: project rules, setup notes, and a short list of durable
preferences. Keep using them for facts that should be obvious at first glance.
Remem is meant for the parts that should not depend on manual upkeep:
- **Automatic capture and recall**: hooks summarize sessions into a SQLite
memory store, while `remem search`, `remem show`, `timeline`, and MCP
`get_observations` retrieve details on demand.
- **A bridge to native memory**: `remem sync-memory --cwd .` writes a compact
`remem_sessions.md` entry for Claude Code native memory when that directory
exists, with a `MEMORY.md` pointer and a size guard. Full detail stays in the
database and is fetched with `remem search`.
- **A human-editable mirror**: `remem export --markdown --output
./remem-memory --project "$PWD"` writes one `.md` file per curated memory to
an empty directory. After editing those files, `remem import markdown --source
./remem-memory` updates existing rows and rebuilds search, entity, embedding,
and current-state indexes. Export refuses non-empty directories to avoid
overwriting manual edits.
- **Governance and auditability**: `remem why <id>`, `remem govern --action
stale --dry-run --json <id>`, `remem status --json`, and `remem usage --days
14 --weeks 8` show why a memory is visible, what would change, store health,
and memory-AI token/cost accounting.
- **Deterministic checks before claims**: local gates include
`cargo test -q context::claude_memory --lib`, `cargo test -q eval::golden
--lib`, `cargo test -q eval::governance --lib`, and `remem eval-e2e --json`.
Do not read this as a published claim that remem beats a carefully maintained
`MEMORY.md` on coding tasks. The flagship no-memory / remem / curated-file A/B
is still a separate benchmark requirement; until it is published, the honest
claim is capability coverage and reproducible local checks.
## Search Architecture
remem uses 4-channel Reciprocal Rank Fusion (RRF) inspired by [Hindsight](https://github.com/vectorize-io/hindsight):
```
Query: "database encryption"
|
+----+------------------------------------+
| 1. FTS5 (BM25) trigram + OR |
| 2. Entity Index 1600+ entities |
| 3. Temporal "yesterday"/"last week" |
| 4. LIKE fallback short tokens |
+-------------+---------------------------+
|
RRF score = sum(1 / (60 + rank_i))
|
Top-K merged results
```
Enhancements:
- Entity graph expansion (2-hop multi-hop retrieval)
- Project-scoped entity search (no cross-project leakage)
- CJK segmentation support
- Chinese-English synonym expansion
- Title-weighted BM25 (`bm25(fts, 10.0, 1.0)`)
- Content-hash deduplication via `topic_key`
- Multi-step retrieval guidance in MCP tool descriptions
## Benchmark Snapshot
### LoCoMo (Informational Only)
Full [LoCoMo](https://github.com/snap-research/locomo) benchmark (10 conversations, 1540 QA pairs after adversarial skip):
This snapshot is a historical footnote and is not a CI or release gate. Use the
golden retrieval eval for deterministic gating; LoCoMo remains useful only for
manual, informational comparison because the methodology is disputed.
| **v1 (fair)** | **56.8%** | 67.1% | 39.0% | 53.9% | 28.1% | per-turn | gpt-5.4 |
| **v2 (optimized)** | **62.7%** | 72.3% | 61.3% | 40.5% | 56.2% | session_summary | gpt-5.4 |
### Internal Eval (1777 real memories)
| MRR | 0.858 |
| Hit Rate@5 | 1.000 |
| Dedup rate | 1.0% |
| Project leak | 0% |
| Self-retrieval | 100% |
### Local QA Eval
```bash
python3 eval/local/run_local_eval.py --db ~/.remem/remem.db --n 20
```
| Overall | **85.0%** |
| Decision | 77.8% |
| Discovery | 87.5% |
| Preference | 100% |
| Source in top-20 | 90.0% |
Requires explicit `--db` plus `.env` with `OPENAI_API_KEY` (optional `OPENAI_BASE_URL`, `OPENAI_MODEL`).
### Sandboxed E2E Eval
```bash
remem eval-e2e
remem eval-e2e --json
```
Runs a deterministic coding-agent memory corpus through the real local REST API
boundary (`POST /api/v1/memories`, then `GET /api/v1/search`) with a temporary
`REMEM_DATA_DIR`. The default run removes the sandbox directory afterward, so it
does not touch `~/.remem` or other real memory data. Use `--keep-data-dir` when
you need to inspect the generated database.
## Token Usage And Cost Reporting
remem records an AI usage ledger for its own background extraction, summary,
compression, and promotion calls. The CLI can report daily and weekly token
usage and estimated cost:
```bash
remem usage --days 14 --weeks 8
remem usage --project /path/to/project --days 30 --weeks 12
```
The report includes calls, input tokens, cache tokens, output tokens, reasoning
tokens, total tokens, estimated USD cost, and a precision note. Usage rows are
tagged by source:
- `anthropic_usage`: provider-reported usage from the Anthropic Messages API
- `codex_log`: exact token counts parsed from the current `codex exec --json`
`turn.completed.usage` event
- `text_estimate`: fallback estimate from prompt/response text length
Cost is an estimate, not an invoice. Historical rows may be text estimates or
may have been repriced from older rows that did not store the exact model.
## Memory AI Configuration
Memory AI execution is configured in `~/.remem/config.toml` (override path with
`REMEM_CONFIG`). Hooks pass only `--host`; the config maps each host to one
profile used by summarize, flush/extract, compress, and dream.
```bash
remem config path
remem config show
remem config set memory_ai.profiles.codex.model gpt-5.2
```
For normal model switching, prefer the higher-level `remem model` commands:
```bash
remem model current
remem model list
remem model use cheap
remem model use balanced --dry-run
remem model use gpt-5.2 --reasoning medium
remem model use haiku --host claude-code
remem model test
remem model test --live
remem model rollback
```
`remem model test` only validates the selected config unless `--live` is set.
`remem model use` saves a rollback backup before writing the config. Built-in
presets are Codex-focused; use explicit model names for Claude Code profiles.
Default Codex profile:
```toml
[memory_ai.hosts."codex-cli"]
memory_profile = "codex"
context_gate = "strict"
context_color = true
capture_adapter = "codex-cli"
[memory_ai.profiles.codex]
executor = "codex-cli"
model = "gpt-5.2"
path = "codex"
```
## Commands
```bash
remem install
remem uninstall
remem doctor
remem search "query"
remem search "query" --branch main --type decision --multi-hop --offset 10
remem search "query" --json
remem show <id>
remem show <id> --json
remem eval
remem eval-e2e --json
remem eval-local
remem backfill-entities
remem encrypt
remem api --port 5567
remem status
remem status --json
remem config show
remem config set memory_ai.profiles.codex.model gpt-5.2
remem model current
remem model list
remem model use balanced --dry-run
remem model use gpt-5.2 --reasoning medium
remem model use haiku --host claude-code
remem model test [--live]
remem model rollback
remem usage --days 14 --weeks 8
remem pending list-failed
remem pending list-failed --json
remem pending retry-failed --dry-run
remem pending purge-failed --dry-run --older-than-days 7
remem govern --action stale --dry-run --json <id>
remem review list
remem review approve <id>
remem review discard <id>
remem review edit <id> --text "updated memory"
remem preferences list
remem preferences add "text"
remem preferences remove 42
remem context --cwd .
remem cleanup --dry-run --json
remem cleanup
remem dream [--project X] [--profile NAME] [--dry-run]
remem install --target codex
remem mcp
remem sync-memory --cwd .
```
### Scriptable JSON output
These commands emit one JSON object and no human text on stdout when `--json`
is set:
| `remem status --json` | `version`, `database`, `totals`, `capture_pipeline`, `pending_observations`, `jobs`, `worker_daemon`, `today`, `top_projects` |
| `remem cleanup --dry-run --json` | `dry_run`, `retention_days`, `plan`, `applied` |
| `remem search ... --json` | `query`, `project`, `memory_type`, `limit`, `offset`, `branch`, `include_stale`, `multi_hop_requested`, `explain_requested`, `count`, `has_more`, `next_offset`, `results`, `raw_hits`, `multi_hop`, `explain_details` |
| `remem show <id> --json` | `found`, `id`, `memory` |
| `remem pending list-failed --json` | `project`, `limit`, `count`, `failed` |
| `remem govern ... --json` | `dry_run`, `action`, `reason`, `affected` |
## REST API
```bash
remem api --port 5567
TOKEN=$(cat ~/.remem/.api-token)
curl -H "Authorization: Bearer $TOKEN" http://127.0.0.1:5567/api/v1/status
```
Library users who build the router directly should call
`remem::api::ensure_api_token()` before `remem::api::build_router(...)`.
| `/api/v1/search?query=&project=&type=&limit=&offset=&branch=&multi_hop=` | GET | Search memories |
| `/api/v1/memory?id=` | GET | Get one memory |
| `/api/v1/memories` | POST | Save memory |
| `/api/v1/status` | GET | System status |
## Security
- SQLCipher encryption at rest (`remem encrypt`)
- Data directory permissions (`0700`)
- Key file permissions (`0600`)
- REST API binds localhost only (`127.0.0.1`) and requires
`Authorization: Bearer $(cat ~/.remem/.api-token)`
- API token file permissions (`0600`)
## Architecture Docs
See [docs/ARCHITECTURE.md](docs/ARCHITECTURE.md) for full internals and data flow.
## Uninstall
```bash
remem uninstall
rm -rf ~/.remem
```
## License
MIT