Head to head · Agent harnesses · October 2026 research run
Conductor vs Letta
Letta scores 59.7 (C) on agent readiness against Conductor's 41.3 (E), and leads in 6 of 7 scored categories. Conductor leads on security & auth. Both do agent harnesses.
Best agent harnesses and coding agents · All 1500 harnesses comparisons
Best memory layers for AI agents · All 353 memory comparisons
Which one, for what
Best for Existing Conductor users planning their move before Cloud closes on 20 November 2026 and the local app winds down in early 2027.
Ahead on
- Security & auth, 45 against 35
Watch for
No new downloads or sign-ups since 4 November 2026
Letta C
Best for Long-lived coding agents and assistants that keep memory and identity across sessions and machines.
Ahead on
- Reliability, 58 against 25
- Schema & documentation, 70 against 60
- Agent ergonomics, 67 against 55
- Payments & pricing, 60 against 0
- Maintenance & community, 85 against 58
Also in its favour
- Runs on your own machine
- Open source
Watch for
The default permission mode is unrestricted, the renamed bypassPermissions, so tool calls aren't confirmed unless the user picks another mode
Why the edge
Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.
Payments & pricing Letta +60
Conductor 0
No new sign-ups since 4 November, free users can't upgrade, and no price is shown. No protocol, no published price, no open free tier, no onboarding (0).
Letta 60
No x402, MPP or L402 (0 of 40). Per-unit API prices are public, $0.10 per active agent a month and $0.00015 a second of tool execution, plus plan prices (20). A $0 plan with bring-your-own keys; no card is mentioned (20). The CLI runs locally without signing in (20). Total 60.
Reliability Letta +33
Conductor 25
Read as local software that is winding down. Installed from Conductor's own download, which stopped taking new users on 4 November 2026 (10). Closed source, so no public CI or issue tracker (0, 0). A dated changelog, newest 0.93.0 on 4 November (15). Version 0.93 (0). 10 + 0 + 0 + 15 + 0 = 25.
Letta 58
Local-software lines, read for the harness. @letta-ai/letta-code on npm with Node.js 22.19 or newer, and PyPI wheels for glibc Linux, macOS 14 and Windows x64 with Python 3.9 or newer stated (20). ci.yml, nightly update smoke tests and Telegram live smoke tests exist, but GitHub's API answered with a rate limit, so run results were unread (15 of 25, unchecked). 332 open issues and pull requests, mostly pull requests; recent bug reports such as recall reading the wrong conversation have no reply yet (15 of 25). 398 tags at 0.34.x with release notes on GitHub, no changelog file, and breaking removals such as AgentFile announced in the README (8 of 15). Pre-1.0 (0). Total 58.
Maintenance & community Letta +27
Conductor 58
0.93.0 on 4 November 2026 (30). Several dated releases in 90 days, per the changelog index (20). Discord, a subreddit and email for support (8). Closed app, no package or CI to read (0). 30 + 20 + 8 + 0 + 0 = 58. The local app gets new models and critical fixes only until early 2027.
Letta 85
v0.34.42 on 6 November 2026 (30). Dozens of releases in 90 days (20). Pull requests are merged daily; recent issues from users have few replies (15 of 25). npm and PyPI packages and the Agent SDK track the releases (12 of 15). Lock files, CI and nightly smoke tests (8 of 10). Total 85.
Agent ergonomics Letta +12
Conductor 55
Harness reading. Each task gets a workspace, branch, terminal and diff, with pull requests and merges from the app, and an API for integrations; not re-read in detail (55).
Letta 67
Harness reading. Toolsets switch with /model, skills load per agent, and subagents run in the background (18 of 25). Context is managed through memory blocks, reflection and dreaming (12 of 20). letta -p --output-format json for scripted runs and an App Server for programmatic control (12 of 20). Conversations resume by agent and conversation id, and memory is git-tracked so changes can be reverted (15 of 20). Runs with no account on the local backend, with one SDK language, TypeScript (10 of 15). Total 67.
Schema & documentation Letta +10
Conductor 60
Harness reading. Docs for workspaces, review and merge, a Conductor API reference page linked from the docs (not read), and security and permissions pages (60).
Letta 70
Harness reading. docs.letta.com serves llms.txt and a Markdown version of every page, with an applies_to block saying which backend and interface each page covers (10). TypeScript types for the Agent SDK and a documented App Server WebSocket protocol, but no JSON Schema or OpenAPI for the harness (15 of 25). Pages say when to use local or cloud backends, subagents and channels (14 of 20). Permission modes and options are typed in the SDK (12 of 15). Example applications and a remote client reference (11 of 15). Releases most days but no changelog file (8 of 15). Total 70.
Security & auth Conductor +10
Conductor 45
Closed app. Telemetry and data handling weren't read beyond the transition notice (10 of 30). A security and permissions page (10 of 20). No prompt-injection guidance found (5). No audit log found (5). SOC 2 Type II report at trust.conductor.build (15 of 20). 10 + 10 + 5 + 5 + 15 = 45.
Letta 35
Harness reading of the framework checklist, as for the other harnesses. 30 for what leaves the machine by default, 20 for approvals and sandboxing, 15 for injection posture, 15 for audit and 20 for the security programme. Letta Cloud is the default backend, so agent state and conversations go to Letta's servers, and telemetry is on by default (10 of 30). The default permission mode is unrestricted; standard, acceptEdits and strict are opt-in, and cloud sandboxes exist for remote work (4 of 20). No prompt-injection guidance found for fetched pages or channel messages (5 of 15). Conversation search and git history of memory give an operator a record of what the agent saw and changed (10 of 15). SECURITY.md routes reports to support@letta.com and scopes out the retired server; no security.txt, bounty or certification found (6 of 20). Total 35.
Score by category
| Category | Weight this run | Conductor | Letta | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 25 | 58 | Letta +33 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 60 | 70 | Letta +10 |
| Agent ergonomics | 13%16.2 | 55 | 67 | Letta +12 |
| Security & auth | 14%17.5 | 45 | 35 | Conductor +10 |
| Payments & pricing | 10%12.5 | 0 | 60 | Letta +60 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 58 | 85 | Letta +27 |
| Transparency & trust | 7%8.8 | 53 | 55 | Letta +2 |
| Negative events | ≤15 | 0 | 0 | |
| Total | E 41.3/100 | C 59.7/100 |
Facts side by side
| Fact | Conductor | Letta |
|---|---|---|
| Kind | Agent harness | Agent harness |
| Vendor | Conductor (joining Meta) | Letta |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | stdio | |
| Auth | OAuth or key | OAuth or key |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | Proprietary. A closed-source Mac app and hosted Conductor Cloud under Conductor's terms | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-11-04 | 2026-11-06 |
| Terms last updated | not read yet | no date given |
| Privacy policy last updated | not read yet | no date given |
| Customer content may train models | not read yet | not found in the text |
| Terms restrict automated access | not read yet | not found in the text |
| Terms restrict benchmarking | not read yet | not found in the text |
| Terms or service can change without notice | not read yet | not found in the text |
| Arbitration or class-action waiver | not read yet | yes |
| Popularity | none | 3.8k stars, 86k npm/wk, 2.2k PyPI/wk |
Verdicts
Conductor
Conductor ran parallel coding agents on the Mac, and Meta is acquiring it. It has taken no new users since 4 November 2026, Cloud turns read-only on 13 November and shuts down on 20 November, and the local app winds down in early 2027, when all user data is deleted.
Letta
Letta's open-source harness gives agents git-tracked memory blocks, skills, subagents and headless JSON runs, with a $0 plan and public per-agent API prices. It starts in the unrestricted permission mode, defaults to Letta Cloud, sends usage telemetry unless LETTA_CODE_TELEM=0 is set, and the V1 API server the comparisons describe is retired.
Before you call either
Conductor
- Export your data from Settings, Account, Export data before 20 November 2026
- Move Cloud workspaces to your Mac with Transfer to local before 13 November
- Plan a move off the local app before early 2027; see the agent-harnesses category for alternatives
Letta
- Start headless runs with an explicit permission mode such as
standardorstrict; the default auto-approves tools - Pass
--backend localfor work that must stay on the machine, since Letta Cloud is the default - Set LETTA_CODE_TELEM=0 in unattended runs if usage events must not be sent
- Use
letta -p --output-format jsonfor scripted runs and parse the JSON, not the terminal output - Don't plan on the retired V1 REST server or
.afAgentFile import; both are gone
Questions
Which is better for AI agents, Conductor or Letta?
Letta scores 59.7 (C) on agent readiness against Conductor's 41.3 (E), and leads in 6 of 7 scored categories. Conductor leads on security & auth.
Are Conductor and Letta open source?
No open-source release is listed for Conductor. Letta is open source (Apache-2.0).
Other comparisons with Conductor or Letta
- Agent Zero vs Conductor
- Agent Zero vs Letta
- Aider vs Conductor
- Aider vs Letta
- Amp vs Conductor
- Amp vs Letta
- Antigravity CLI vs Conductor
- Antigravity CLI vs Letta
- Auggie CLI vs Conductor
- Auggie CLI vs Letta
- AXLR vs Conductor
- AXLR vs Letta
- Claude Code vs Conductor
- Claude Code vs Letta
- Cline vs Conductor
- Cline vs Letta
- Conductor vs Crush
- Conductor vs Cursor CLI
- Conductor vs DeepSeek Harness (dsh)
- Conductor vs dsh-superagent (DeepSeek)
- Conductor vs Devin
- Conductor vs Droid CLI
- Conductor vs Pi
- Conductor vs Emdash
- Conductor vs Gemini CLI
- Conductor vs GitHub Copilot CLI
- Conductor vs goose
- Conductor vs Harness²
- Conductor vs HarnessRouter
- Conductor vs Jules
- Conductor vs Junie CLI
- Conductor vs Kilo Code CLI
- Conductor vs Kimi Code CLI
- Conductor vs Kiro CLI
- Conductor vs mini-swe-agent
- Conductor vs MiniMax Code
- Conductor vs Mistral Vibe CLI
- Conductor vs Muse Code
- Conductor vs OpenAI Agents API
- Conductor vs OpenAI Codex
- Conductor vs OpenCode
- Conductor vs OpenHands
- Conductor vs OpenMausBot
- Conductor vs Orca
- Conductor vs Paseo
- Conductor vs Prime Agent
- Conductor vs Qoder CLI
- Conductor vs Qwen Code
- Conductor vs Mirror CLI
- Conductor vs Rovo Dev CLI
- Conductor vs Sculptor
- Conductor vs T3 Code
- Conductor vs Traycer
- Conductor vs Unstoppable
- Conductor vs Verdent
- Conductor vs Vibe-Trading
- Conductor vs Warp (Warp Agent CLI and the Oz Agent API)
- Crush vs Letta
- Cursor CLI vs Letta
- DeepSeek Harness (dsh) vs Letta
- dsh-superagent (DeepSeek) vs Letta
- Devin vs Letta
- Droid CLI vs Letta
- Pi vs Letta
- Emdash vs Letta
- Gemini CLI vs Letta
- GitHub Copilot CLI vs Letta
- goose vs Letta
- Harness² vs Letta
- HarnessRouter vs Letta
- Jules vs Letta
- Junie CLI vs Letta
- Kilo Code CLI vs Letta
- Kimi Code CLI vs Letta
- Kiro CLI vs Letta
- Letta vs mini-swe-agent
- Letta vs MiniMax Code
- Letta vs Mistral Vibe CLI
- Letta vs Muse Code
- Letta vs OpenAI Agents API
- Letta vs OpenAI Codex
- Letta vs OpenCode
- Letta vs OpenHands
- Letta vs OpenMausBot
- Letta vs Orca
- Letta vs Paseo
- Letta vs Prime Agent
- Letta vs Qoder CLI
- Letta vs Qwen Code
- Letta vs Mirror CLI
- Letta vs Rovo Dev CLI
- Letta vs Sculptor
- Letta vs T3 Code
- Letta vs Traycer
- Letta vs Unstoppable
- Letta vs Verdent
- Letta vs Vibe-Trading
- Letta vs Warp (Warp Agent CLI and the Oz Agent API)
- Clawboo vs Conductor
- Clawboo vs Letta
- CLI Manager vs Conductor
- CLI Manager vs Letta
- Conductor vs Harness
- Conductor vs Paperclip
- Conductor vs Parallax
- Harness vs Letta
- Letta vs Paperclip
- Letta vs Parallax
Machine-readable
- This page as Markdown
/compare/conductor-vs-letta.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/conductor.json·/api/v1/tools/letta.json - From a terminal
anchor compare conductor letta(the CLI) - Over MCP
compare_tools {"a": "conductor", "b": "letta"}at/mcp, no key