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.

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Which one, for what

Conductor E

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

CategoryWeight this runConductorLettaEdge
Reliability16%202558Letta +33
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26070Letta +10
Agent ergonomics13%16.25567Letta +12
Security & auth14%17.54535Conductor +10
Payments & pricing10%12.5060Letta +60
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85885Letta +27
Transparency & trust7%8.85355Letta +2
Negative events≤1500
TotalE 41.3/100C 59.7/100

Facts side by side

FactConductorLetta
KindAgent harnessAgent harness
VendorConductor (joining Meta)Letta
Hosted endpointno (local only)no (local only)
Transportsstdio
AuthOAuth or keyOAuth or key
PricingPaidFreemium
x402nono
LicenceProprietary. A closed-source Mac app and hosted Conductor Cloud under Conductor's termsApache-2.0
Read-only variant documentednono
llms.txtnoyes
Last release2026-11-042026-11-06
Terms last updatednot read yetno date given
Privacy policy last updatednot read yetno date given
Customer content may train modelsnot read yetnot found in the text
Terms restrict automated accessnot read yetnot found in the text
Terms restrict benchmarkingnot read yetnot found in the text
Terms or service can change without noticenot read yetnot found in the text
Arbitration or class-action waivernot read yetyes
Popularitynone3.8k 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

  1. Export your data from Settings, Account, Export data before 20 November 2026
  2. Move Cloud workspaces to your Mac with Transfer to local before 13 November
  3. Plan a move off the local app before early 2027; see the agent-harnesses category for alternatives

Letta

  1. Start headless runs with an explicit permission mode such as standard or strict; the default auto-approves tools
  2. Pass --backend local for work that must stay on the machine, since Letta Cloud is the default
  3. Set LETTA_CODE_TELEM=0 in unattended runs if usage events must not be sent
  4. Use letta -p --output-format json for scripted runs and parse the JSON, not the terminal output
  5. Don't plan on the retired V1 REST server or .af AgentFile 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

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