Head to head · Agent harnesses · October 2026 research run

Letta vs Verdent

Letta scores 59.7 (C) on agent readiness against Verdent's 39.7 (E), and leads in 6 of 7 scored categories. Both do agent harnesses.

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Which one, for what

Letta C

Best for Long-lived coding agents and assistants that keep memory and identity across sessions and machines.

Ahead on

  • Reliability, 58 against 43
  • Schema & documentation, 70 against 55
  • Agent ergonomics, 67 against 35
  • Payments & pricing, 60 against 20
  • Maintenance & community, 85 against 61

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

Verdent E

Best for A person who wants a desktop app to plan and run several coding tasks at once, possibly on their own Claude Code or Codex.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

No CLI, print mode, API or SDK, so a pipeline can't start or read a run except through a paired chat bot

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 +40

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.

Verdent 20

Harness reading of the published rubric, scored on the Verdent subscription the agent needs. No payment protocol (0). Plan prices from $5 a month, top-up prices and the credit value of about $0.059 are public without a login (20). Free Mode and the free trial ended on 29 October 2026, so there is no free tier (0). A person signs up in a browser (0). 0+20+0+0 = 20.

Agent ergonomics Letta +32

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.

Verdent 35

Harness reading. MCP servers per project or globally, subagents, skills and rules, but no per-tool disabling or deferred loading found (10). No output-size, turn-limit or budget controls for a run were found beyond credit balances (5). No exit codes or error format, since there is no headless mode (3). Parallel workers in git worktrees and a review column make runs reviewable and reversible, with no resume by ID documented (10). No CLI, API or SDK. A pipeline can only reach Manager through a paired Telegram, Slack or Feishu bot (7). 10+5+3+10+7 = 35.

Maintenance & community Letta +24

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.

Verdent 61

Closed service. v2.18.0 on 29 October 2026, eight days before this check (30). More than three dated releases in the 90 days from 8 August, among them 2.10.0 to 2.18.0 (20). A dated public changelog, a support address, Discord and a subreddit, with no public tracker to read reply times (8). No official SDK or MCP server to keep current (0). No public packages or CI to judge (3). 30+20+8+0+3 = 61.

Reliability Letta +15

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.

Verdent 43

Local-package reading, as for the other closed-source harnesses. The desktop app installs from verdent.ai with macOS 11 or later and 64-bit Windows 10 and 11 stated, and the extension from the editor marketplaces, but not from a package registry (15). No public CI or test suite, since the source isn't published (0). No public issue tracker, every task runs through Verdent's servers, and no status page was found, so there is no readable record (5). A dated changelog by version, with the end of Free Mode called out in v2.18.0, but no breaking-change sections (8). 2.18.0, generally available (15). 15+0+5+8+15 = 43.

Schema & documentation Letta +15

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.

Verdent 55

Framework reading for a harness. No schema for settings or output, only mcp.json examples in the standard mcpServers shape (5). Every current docs page has a Markdown twin at the same path with .md, though no llms.txt (10). The docs say when to use Agent Mode or Plan Mode and what Plan Mode can't do, but the Agent Mode page lists the actions that need approval only as "certain tool executions" and "destructive operations" (12). Modes and BYOA agent types are enumerated, permissions are not (5). Examples on the MCP, BYOA and messaging pages, and a recovery page, with no error codes (8). Version numbers and a dated public changelog (15). The archived 1.0 docs are still served beside the current ones. 5+10+12+5+8+15 = 55.

Score by category

CategoryWeight this runLettaVerdentEdge
Reliability16%205843Letta +15
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27055Letta +15
Agent ergonomics13%16.26735Letta +32
Security & auth14%17.53533Letta +2
Payments & pricing10%12.56020Letta +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88561Letta +24
Transparency & trust7%8.85555even
Negative events≤150-2
TotalC 59.7/100E 39.7/100

Facts side by side

FactLettaVerdent
KindAgent harnessAgent harness
VendorLettaVerdent AI, Inc.
Hosted endpointno (local only)no (local only)
Transportsstdio
AuthOAuth or keyOAuth or key
PricingFreemiumPaid
x402nono
LicenceApache-2.0Proprietary. The terms of use from Verdent AI, Inc. forbid reverse engineering or copying any component, and no source is published
Read-only variant documentednoyes
llms.txtyesno
Last release2026-11-062026-10-29
Terms last updatedno date given2026-05-25
Privacy policy last updatedno date given2026-05-26
Customer content may train modelsnot found in the textyes
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waiveryesnot found in the text
Popularity3.8k stars, 86k npm/wk, 2.2k PyPI/wknone

Verdicts

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.

Verdent

A desktop and editor coding agent that splits a goal into parallel workers in git worktrees, with a read-only Plan Mode, MCP servers and the option to run workers on Claude Code or Codex. It has no CLI, API or sandbox, sends context through Verdent's servers, and has had no free tier since 29 October 2026.

Before you call either

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

Verdent

  1. Don't plan to drive Verdent headless. Hand the task to the person using the desktop app, or use a harness with a print mode
  2. Start large changes in Plan Mode and review plan.md before switching to Agent Mode
  3. Add MCP servers in the project's .mcp.json or ~/.verdent/mcp.json in the mcpServers shape
  4. Keep work under git, since rollback relies on git and there is no sandbox
  5. Budget in credits at about $0.059 each, because there is no free allowance since 29 October 2026

Questions

Which is better for AI agents, Letta or Verdent?

Letta scores 59.7 (C) on agent readiness against Verdent's 39.7 (E), and leads in 6 of 7 scored categories.

Are Letta and Verdent open source?

Letta is open source (Apache-2.0). No open-source release is listed for Verdent.

Other comparisons with Letta or Verdent

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