letta-ai/letta-code is an agent harness for building assistants that retain memory, identity, and experience across interactions instead of treating each task as isolated. Developers use it through local, desktop, browser, or messaging interfaces for interactive or continuously running agents, and its catalogue entries configure the agents' skills, instructions, rules, and behavior.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add letta-ai/letta-code --skill syncing-memory-filesystemgit clone --depth 1 https://github.com/letta-ai/letta-codeWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/letta-ai/letta-code/syncing-memory-filesystem)<a href="https://agentmods.dev/skills/letta-ai/letta-code/syncing-memory-filesystem"><img src="https://agentmods.dev/badge/skills/letta-ai/letta-code/syncing-memory-filesystem/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/letta-ai/letta-code/syncing-memory-filesystem"><img src="https://agentmods.dev/badge/skills/letta-ai/letta-code/syncing-memory-filesystem.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00042 | $0.01747 |
| Opus 5.5 | $0.00017 | $0.00699 |
| Sonnet 5.5 | $0.00008 | $0.00349 |
| Haiku 4.5 | $0.00004 | $0.00175 |
Grade A, and why
syncing-memory-filesystem scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 27d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 187 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MemFS Repository Repair
Use this skill only when the Git repository behind an agent's memory is not
setting up or syncing correctly. For ordinary memory reads and edits, use the
memory files without loading this skill. Delegate incidental upkeep during another
task to the background memory subagent. When memory repair is the user's main
request, diagnose and repair it directly, then verify the result before reporting
success. If a memory worker you launched may still be running, wait for it: re-read
its output file until it ends with [Task completed] or [Task failed] before
editing memory files or changing Git state. While the harness reports a repair in
progress, leave both alone as well; that worker edits $MEMORY_DIR in place.
Current Model
MemFS is a Git repository projected onto the computer where the agent is
running. $MEMORY_DIR is the repository root. There is no second memory/
directory inside it.
The repository can use either memory layout. Inspect its current tree and the memory rules in the system prompt before editing files:
Root layout Existing layout
$MEMORY_DIR/ $MEMORY_DIR/
├── MEMORY.md # root index ├── system/ # in-context memory
├── persona.md # core memory ├── reference/ # deferred memory
├── <topic>/ └── skills/ # agent-owned skills
│ └── MEMORY.md # child index
└── skills/ # agent-owned skills
Cloud-backed agents have a hosted MemFS remote. Local-backend agents keep a local-only Git repository and do not need a remote or cloud credentials.
The agent doing the memory work commits its changes. After each turn, the harness pushes
clean committed changes for cloud-backed agents. Local-backend commits remain
on the current machine. Do not run git push for normal MemFS sync; let the
harness push after the turn.
Committed memory changes do not alter the current compiled prompt immediately.
Use /recompile when the current conversation must see changed core memory
right away. Otherwise, the next prompt compilation or conversation will use
the committed revision.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 27d ago Changed · +8 lines 28d6ecbde786
- 1mo ago Changed · -1 lines 8dd69c4bf99a
- 1mo ago First seen · 180 lines · 42 tokens per session scan A a3884fbd40cc
syncing-memory-filesystem is a skill published in the GitHub repository letta-ai/letta-code (3,667 stars, last pushed today), licensed Apache-2.0. It adds 42 tokens to every session and 1,747 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
github-ops
GitHub CLI for issues, PRs, code search, CI logs, releases, and API queries. Requires gh CLI and auth.
pre-pr
Prepare a Honcho change for a pull request to plastic-labs/honcho. Invoke before opening a PR, when drafting a PR body, when asked if a branch is PR-ready, or when filling the pull request template. Checks the linked issue, required tests and docs, then writes Description / Proofs / Fixes.
init
Turn on Rekal memory in the current repository by running rekal init. Use when the user asks to initialize or set up Rekal here, or when a rekal command reported the repository is not initialized. Once per repository. Do not offer this merely because a repo lacks a .rekal/ store — most repos do not want one.
memex-sync
Sync Zettelkasten cards across devices via git.
unforgit-memory
Use Unforgit MCP tools as durable repository memory for decisions, conventions, gotchas, and playbooks.
end
Close a work session — log what happened, update state and the decision log, propose durable memory updates, and check for uncommitted or unpushed work.