BREAKING. memwalk is no longer a personal-activity recorder; it's
an AI tool for asking questions about any codebase, with cached
SSM state per directory.
What's gone
-----------
- sources/git.py, sources/bash.py — personal activity collectors
- snapshot.py — daily snapshot rotation
- ingest.py — orchestration tied to git+bash use case
- standup / update CLI commands
- All v0.1 config keys (scan_paths, bash settings, bootstrap_days)
What's new
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- corpus.py — walk a codebase, filter source files, build a single
ingest-ready text block with a stable manifest hash
for cache invalidation.
- cache.py — per-directory cached state + sidecar metadata JSON.
Cache key = sha256(abs_path)[:16]; freshness check =
manifest hash over (rel_path, size, mtime_ns).
- engine.py — shared digest/ask orchestration used by both CLI
and MCP server.
- cli.py — init, digest, ask, list, drop, status, mcp.
- mcp_server.py — tools: digest, ask, list_caches, drop_cache, status.
- config.py — drastically simplified (just model+inference defaults).
The MCP server still ships as `memwalk mcp` and works the same way with
Claude Code / opencode.
Validated on memwalk's own source: digest in ~4s, ask answers in ~3s
(model+state load) including "list CLI commands", "where is cache
stored, what filename pattern", "how does cache invalidation work" —
all accurate down to specific details (sha256 length, file extensions,
metadata field semantics).
memba dep installed via git URL until both packages reach PyPI.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
136 lines
4.5 KiB
Markdown
136 lines
4.5 KiB
Markdown
# memwalk
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> Ask AI about any codebase — local, cached, SSM-state-backed.
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`memwalk` reads an entire codebase into a Mamba-based LLM via persistent
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state, so subsequent questions answer in <1 s without re-reading anything.
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The state is byte-portable (via [memba](https://github.com/emil28092005/Memba))
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and cached per-directory by file manifest hash, so re-asking is free until
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the source changes.
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Built on **memba** for state persistence and
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**[NVIDIA Nemotron-3-Nano-4B](https://huggingface.co/nvidia/NVIDIA-Nemotron-3-Nano-4B-GGUF)**
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(hybrid Mamba-2 + Transformer, 1M training context) for inference.
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## What makes this different from Cursor / Cody / Aider
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| Tool | Approach | Whole-repo question |
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|--------------|--------------------------------|--------------------------|
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| Cursor | Embed chunks, retrieve at Q | Fragmented context |
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| Cody | BM25 + dense embeddings (RAG) | Pre-indexed, retrieved |
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| Aider | Symbol-level repo map | Signatures only |
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| **memwalk** | **Read everything once, cache the SSM state** | Holistic answer; <1s re-asks |
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SSM state is **fixed-size** (Mamba's defining property), so even a 1M-token
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codebase compresses into a constant-size file (~85 MB at our settings).
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Reload is millisecond-scale — re-asking a freshly-cached repo costs no
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model inference until you ask the next question.
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## Status
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v0.2 — alpha. Works for the maintainer end-to-end; APIs and on-disk format
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may shift.
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## Install
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memba is not on PyPI yet, so install via git:
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```bash
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pip install git+https://github.com/emil28092005/memwalk.git
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# (pulls memba @ main as a transitive git dep)
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```
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Or from a local clone:
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```bash
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pip install -e ~/Desktop/Coding/memwalk
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```
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Make sure you have a GGUF Mamba-2 / hybrid model. Recommended:
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```bash
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hf download nvidia/NVIDIA-Nemotron-3-Nano-4B-GGUF \
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NVIDIA-Nemotron3-Nano-4B-Q4_K_M.gguf \
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--local-dir ~/.memwalk/models
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```
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## Quickstart
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```bash
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memwalk init # one-time: set model path
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memwalk digest ~/Desktop/Coding/myrepo # first time: read everything (~10s)
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memwalk ask ~/Desktop/Coding/myrepo "How does auth work?" # <1s
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memwalk ask ~/Desktop/Coding/myrepo "Which file owns the migration logic?"
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memwalk list # show all cached codebases
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memwalk drop ~/Desktop/Coding/myrepo # invalidate cache
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memwalk status # config + cache summary
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```
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`memwalk ask` auto-digests on first use, so the explicit `digest` step is
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optional. The cache is invalidated automatically when any source file
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changes (mtime / size).
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## Use from an AI agent (MCP)
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```bash
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memwalk mcp # starts a stdio MCP server
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```
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Tools: `digest(path)`, `ask(path, question)`, `list_caches()`,
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`drop_cache(path)`, `status()`.
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### Claude Code
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```bash
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claude mcp add memwalk -- memwalk mcp
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```
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Or by hand in your MCP config:
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```json
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{
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"mcpServers": {
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"memwalk": { "command": "memwalk", "args": ["mcp"] }
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}
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}
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```
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### opencode / Hermes / other MCP clients
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Same shape — they all consume `{"command": "memwalk", "args": ["mcp"]}`.
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After the agent connects it sees `mcp__memwalk__digest`,
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`mcp__memwalk__ask`, etc. Typical flow:
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> User: *"What changed in the migrations folder of my CU\_Points repo this month?"*
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>
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> Agent: calls `mcp__memwalk__ask(path="~/Desktop/Coding/AI/CU_Points",
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> question="...")`. memwalk auto-digests if needed, returns answer.
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## What does it actually do well?
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Validated on memba's own codebase (13 files, ~63 K chars):
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- Listed every header field of the state file format **in order**
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- Explained the architectural reason for the `eval+sample` rewrite
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- Identified which side of the C/Python boundary writes the MEMB trailer
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- Listed all CLI subcommands accurately
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- Suggested correct file path + approach for adding a new command
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Recall is **descriptive-strong** — facts that are in the source. It is not
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a substitute for a real debugger or a code generator. For complex
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reasoning over small snippets, a bigger code-tuned model is still better.
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## Limits
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- **Single-shot context, not chunked retrieval.** Whole corpus must fit in
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`n_ctx` (default 32 K tokens ≈ ~120 K chars). Bigger repos: bump `n_ctx`,
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use a beefier GPU, or filter `INCLUDE_SUFFIXES` in `corpus.py`.
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- **No code-aware filtering yet** — every text file under the root is
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read. Use `.gitignore`-style filtering in v0.3.
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- **No GPU-less mode tested** — should work on CPU but slow.
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## License
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MIT.
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