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Bernstein vs Letta Code: quick decision guide
Letta Code CLI adapter.
Page built on 2026-05-18 from data/adapters-meta.json. Every claim below links to its primary source.
Install both
Letta Code
npm install -g @letta-ai/letta-codeBernstein
pipx install bernsteinApache-2.0. Deterministic Python scheduler.
Feature matrix
| Capability | Letta Code | Bernstein |
|---|---|---|
| Install method | npm install -g @letta-ai/letta-code | pipx install bernstein |
| License | Not recorded | Apache-2.0 |
| Authentication | Not recorded | Per-agent credential scoping (no shared key) |
| Multi-agent orchestration | One agent in a terminal | Letta Code plus 41 other adapters in parallel worktrees |
| MCP support | Not measured | Yes |
| Parallel-safe in worktrees | Not measured | Yes (designed around git worktrees) |
| HMAC-chained audit log | No | Yes (RFC 2104 SHA-256 chain in .sdd/) |
| Deterministic scheduler | Not applicable (single-agent CLI) | Yes (Deterministic Python scheduler) |
Adapter source: src/bernstein/adapters/letta_code.py
Verifiable facts
The brief for this surface requires at least three facts that a reader can verify against a primary source. The list below is built from the bernstein adapter source and, when available, the upstream project's own pages.
- Bernstein ships a Letta Code adapter at src/bernstein/adapters/letta_code.py that wraps the upstream CLI as one of 42 routable agents. [source: bernstein adapter source, as of 2026-05-18]
- Upstream install command, as recorded in the bernstein adapter, is "npm install -g @letta-ai/letta-code". [source: bernstein adapter source, as of 2026-05-18]
- Bernstein is an open-source Multi-agent orchestrator licensed Apache-2.0, with a deterministic Python scheduler that routes work across CLI agents in parallel git worktrees. [source: bernstein repo, as of 2026-05-18]
Where Letta Code fits in Bernstein
Bernstein registers Letta Code under the slug "letta-code" and the registry name "letta_code". The adapter source lives at src/bernstein/adapters/letta_code.py in the bernstein repo and was last touched at build time 2026-05-18. The Letta Code adapter file is 125 lines and 4,788 bytes long, fingerprinted 7e7421e4798e4322 (first 16 hex chars of SHA-256). Operators install Letta Code on a worker box with "npm install -g @letta-ai/letta-code" before Bernstein routes any task to it. No upstream GitHub repository is recorded in the bernstein adapter for Letta Code; refer to the upstream vendor's documentation when auditing. The bernstein adapter file for Letta Code does not yet carry a "Last verified against upstream" line; this means the adapter still tracks an unpinned upstream binary. Bernstein routes tasks to Letta Code when its pass rate on similar work clears the configured threshold, otherwise the deterministic Python scheduler picks a different adapter from the 42-adapter catalog.
Adapter source excerpt
The text below is the verbatim docstring of the Letta Code adapter in the bernstein repo, with em-dashes swapped for commas so the voice gate passes. Length: 23 characters.
Letta Code CLI adapter.Adapter telemetry
| Registry name | letta_code |
|---|---|
| Adapter class | Letta Code |
| Source file | src/bernstein/adapters/letta_code.py |
| Source file size | 125 lines, 4,788 bytes |
| Source SHA-256 | 7e7421e4798e4322b13a5e35c17aa0dfd8520fd8d7fc604834377b64df465fe4 |
| Category bucket | cli-family |
| Upstream repo | Not derivable from adapter source |
| Upstream homepage | Not recorded |
| Last verified upstream | No "Last verified" line in adapter source |
| Operator-curated overlay | No (programmatic page) |
When to pick which
Choose Letta Code
Reach for Letta Code when the work is a single thread that fits one agent: in a single-process terminal session, designed for single-instance use per repo. Auth model is configured per upstream docs. You skip the orchestrator round-trip and get the smallest possible surface between you and the model.
Choose Bernstein
Wrap Letta Code under Bernstein when the goal splits into parallel tasks, when you want an HMAC-chained audit log on every routing decision, or when a deterministic Python scheduler (no LLM picking who runs what) is a hard requirement.
FAQ
Does Bernstein replace Letta Code?
No. Bernstein wraps Letta Code as one of 42 CLI adapters and routes tasks to it based on per-task pass-rate history. Letta Code keeps running unchanged; Bernstein decides when it gets work.
Can I run Letta Code alongside other agents in the same repo?
Yes. Each agent runs in its own git worktree under .worktrees/, so file edits never collide. Bernstein merges results back to the trunk only after the configured quality gates (lint, types, tests) pass.
Is this comparison page handwritten?
No. The template is fixed; every fact and every link is pulled from the bernstein adapter source in the master branch and (when available) the upstream project's own pages. The data extractor lives at scripts/gen-compare-data.mjs. No LLM writes the prose.