memir 0.3.3

Local memory for coding agents: deterministic zero-token writes, a first-class failure guard (never repeat a mistake), and a token-efficient briefing. Local CPU semantic recall — no API keys, no cloud.

🧠 Memir

The memoir your coding agent writes for itself. Long-term memory for coding agents that doesn't eat your context window. Local-first. Zero API keys. And it never lets the agent repeat a mistake.

Memir = memory + memoir + Mímir, the Norse keeper of memory and wisdom. Your agent keeps a memoir; Memir is where it lives.

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The problem

Every coding agent forgets. Switch chats, hit the context limit, start a new session — and it re-asks what it already knew, re-decides what you already decided, and repeats the exact mistake it made an hour ago.

The common "fix" is to stuff the whole history back into the prompt every turn. That burns thousands of tokens per request and still overflows as the project grows.

The idea

Memir stores three kinds of memory in a tiny local SQLite file:

kind	what it captures
fact	durable truths about the project (endpoints, conventions, constraints)
decision	a choice and the reason for it, so it isn't relitigated
failure	what was tried, why it failed, and the lesson — a first-class memory

Then it hands the agent a token-budgeted briefing at the start of a session and a failure guard it can check before trying something.

Writing a memory costs 0 tokens and 0 API calls — it's a local insert, sub- millisecond. Compare that to memory frameworks that run an LLM extraction call on every add.

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Why it's different

• First-class FAILURE memory. Most memory tools remember facts. Memir remembers mistakes — what failed, why, and what to do instead — and blocks the repeat. That's the load-bearing feature for a coding agent.
• 0-token, deterministic writes. No LLM in the capture path. Nothing to bill, nothing to rate-limit, nothing to go down.
• Local semantic recall by default. Ships with a retrieval-tuned, numpy-only embedding model (model2vec potion-retrieval-32M) that runs in ~1 ms on a CPU — no GPU, no torch, no API. Paraphrase matching works out of the box, and gracefully falls back to keyword recall if the model can't be loaded.
• Anti-bloat. Write-time dedup plus a safe consolidate() that only merges genuine restatements — it will never collapse two distinct facts.
• Bounded context cost. A naive "replay everything" agent grows without bound; the briefing here stays inside a token budget you set.
• Plugs into any agent via MCP. One stdio server works with Cursor, Claude Desktop, Cline, VS Code, Windsurf, …

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Install

pip install memir

The base install is light — model2vec + numpy only (no torch, no GPU, no API key). Optional local CPU accuracy features are opt-in extras:

pip install "memir[rerank]"      # cross-encoder reranker (precision second stage)
pip install "memir[nli]"         # NLI reasoner (contradiction detection)
pip install "memir[contextual]"  # contextual BGE encoder (stronger multi-hop)
pip install "memir[ml]"          # all of the above

Warm the model cache once so later runs work fully offline:

memir setup      # downloads the CPU model, initialises the store
memir start      # starts the MCP server (stdio) for your editor/agent

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Quickstart (Python)

from memir import Memir

brain = Memir("my-project")          # local model loads automatically (CPU)

# remember things (0 tokens, sub-ms, no API)
brain.remember_fact("The billing job MUST run in UTC; our partner reports in UTC.")
brain.record_decision("Use SQLite FTS5 for recall.", reason="100x faster than scanning.")

# record a failure so it's never repeated
brain.record_failure(
    attempt="POSTed the whole batch to /v1/ingest in one request.",
    reason="The gateway silently drops bodies >256KB and returns an empty 200.",
    lesson="Chunk uploads under 256KB and verify each ack id.",
)

# BEFORE trying something, check the failure guard
if hits := brain.check_failure("send the full batch to /v1/ingest at once"):
    print("⛔", hits[0].lesson)   # -> Chunk uploads under 256KB and verify each ack id.

# start a fresh session fully informed, within a token budget
print(brain.briefing(budget_tokens=300))

Auto-capture from real errors

# parses the traceback, decides it's non-obvious, stores it as a failure:
brain.capture_error("RuntimeError: gateway returned 200 with empty body — silently dropped")

# a textbook typo is judged self-evident and skipped (no bloat):
brain.capture_error("NameError: name 'foo' is not defined")   # -> None

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Command line

memir remember "Deploys go out via the blue/green pipeline only."
memir decision "Adopt SQLite WAL" --why "concurrent reads during writes"
memir failure  "Dropped the prod table" --why "ran migration w/o backup" \
               --lesson "snapshot before every migration"
memir recall   "how do we deploy?"
memir check    "run the migration now"      # failure guard
memir briefing --budget 300
memir stats
memir doctor                                 # environment + MCP config check

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Use it from your editor (MCP)

Memir ships a Model Context Protocol server (stdio JSON-RPC).

Cursor / Windsurf / Claude Desktop — add to your MCP config:

{
  "mcpServers": {
    "memir": {
      "command": "memir",
      "args": ["start"],
      "env": { "MEMIR_PROJECT": "my-project", "MEMIR_DB": ".memir/memir.db" }
    }
  }
}

VS Code (.vscode/mcp.json):

{ "servers": { "memir": { "command": "memir", "args": ["start"] } } }

Tools exposed: remember_fact, record_decision, record_failure, recall, check_failure, briefing, capture_error, stats, consolidate.

Set MEMIR_EMBED=0 to force keyword-only mode (skips the model entirely). Override the model with MEMIR_MODEL=minishlab/potion-base-8M (30 MB, faster).

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Benchmarks

Memir is measured against real memory backends (mem0, cognee, graphiti, letta) and an oracle upper bound under a single uniform LLM judge. The honest headline: Memir matches the top accuracy tier while injecting ~10× fewer memory tokens per turn, locally and with zero-token writes. See docs/BENCHMARKS.md for the full tables, the competitor head-to-heads, and the documented limits (relational multi-hop at large scale).

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License

MIT — a permissive open-source license. Free to use, modify, and distribute, including commercially, with attribution.