Head to head · Agent harnesses · October 2026 research run

Letta vs Warp (Warp Agent CLI and the Oz Agent API)

Letta scores 59.7 (C) on agent readiness against Warp (Warp Agent CLI and the Oz Agent API)'s 57.6 (C), and leads in 4 of 7 scored categories. Warp (Warp Agent CLI and the Oz Agent API) leads on schema & documentation, security & auth and transparency & trust. 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 52
  • Payments & pricing, 60 against 20

Also in its favour

  • Runs on your own machine
  • No incidents deducted, where Warp (Warp Agent CLI and the Oz Agent API) loses 3 points for them

Watch for

The default permission mode is unrestricted, the renamed bypassPermissions, so tool calls aren't confirmed unless the user picks another mode

Warp (Warp Agent CLI and the Oz Agent API) C

Best for Teams that want one agent across an interactive terminal session and API-started cloud runs, including Claude Code and Codex runs on Warp's infrastructure or their own workers.

Ahead on

  • Schema & documentation, 89 against 70
  • Security & auth, 52 against 35
  • Transparency & trust, 69 against 55

Watch for

The warp CLI has no print or headless mode. Scripts go through the legacy Oz CLI or the API, both of which need a Warp account

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.

Warp (Warp Agent CLI and the Oz Agent API) 20

Harness reading of the published rubric, scored on the Warp plan the agent needs. No payment protocol (0). Plan prices are public, and Warp-provided inference is billed at public API rates on paid plans, but the agent-hour platform rate and compute rate for cloud runs were not on the pricing page (10). Free is $0 and includes Warp Agent CLI access, but no bundled Warp inference, so the agent runs only with purchased usage or your own provider key. Whether sign-up asks for a card was not tested (10). A person signs in through a browser or device code, and API keys are created by hand in the Oz web app or the Warp app (0). 0 + 10 + 10 + 0 = 20. Warp's terms bar any robot, scraper or other automated means to access its Services, so this run pauses its hosts and the readings from warp.dev pages are per the 18 October check, not re-read on 4 November.

Schema & documentation Warp (Warp Agent CLI and the Oz Agent API) +19

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.

Warp (Warp Agent CLI and the Oz Agent API) 89

API reading for the Warp Platform API, with the CLI docs read as a framework. docs.warp.dev/openapi.json is OpenAPI 3.0.0 with 293 component schemas and bearer authentication (25). llms.txt with per-section Markdown bundles, including one for the Warp Agent CLI and one for the Automation Platform (10). The run request schema says when each field applies (prompt unless a skill is given, on_behalf_of only for agent keys on team runs), and the CLI permissions page states each default and when auto-approve bypasses the denylist (15). Run modes, states and permission values are enumerated, and request bodies are typed objects (13). Curl and SDK examples throughout, and an error catalogue of RFC 7807 bodies with a machine-readable code, retryable flag and trace ID per error (14). The API sits under /api/v1 with info version 1.0.0, and the weekly changelog has an Oz updates section, but there is no API-only changelog (12). 25 + 10 + 15 + 13 + 14 + 12 = 89. Warp's terms bar any robot, scraper or other automated means to access its Services, so this run pauses its hosts and the readings from warp.dev pages are per the 18 October check, not re-read on 4 November.

Security & auth Warp (Warp Agent CLI and the Oz Agent API) +17

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.

Warp (Warp Agent CLI and the Oz Agent API) 52

Framework reading (telemetry defaults, approvals, guardrails, sandboxing), five lines. The FAQ says the built-in harness runs server-side, so prompts, file contents and command output pass through Warp. The privacy page says AI interactions and console inputs may be collected unless Help improve Warp is off, and the security overview says data collection is on by default for Free and paid teams and off on Business and Enterprise. The opt-out is documented in the desktop app's settings, not for the CLI. Personal and agent keys can expire after 1, 30 or 90 days, and provider keys stay in the device's secure storage (14). Per-action permissions with always_ask, agent_decides and always_allow, edits always shown as a diff under agent_decides, a default denylist and child agents asking first. Auto-approve bypasses the user's denylist by default, and no local OS sandbox is documented. Cloud runs use a Docker sandbox as a non-root user with passwordless sudo (11). No prompt-injection guidance was found in the CLI, platform or factory pages read, and secret redaction is off by default (4). Cloud runs record transcripts, tool calls and logs, the API returns timelines and conversations, the app has a Network Log, and the Enterprise Analytics API can filter tool calls for audit (11). SECURITY.md names security@warp.dev and private GitHub advisories, SOC 2 Type II is stated with a trust centre and a subprocessor list. No security.txt and no bug bounty were found, and the GitHub advisory list was not read (12). 14 + 11 + 4 + 11 + 12 = 52. Warp's terms bar any robot, scraper or other automated means to access its Services, so this run pauses its hosts and the readings from warp.dev pages are per the 18 October check, not re-read on 4 November.

Transparency & trust Warp (Warp Agent CLI and the Oz Agent API) +14

Letta 55

Apache-2.0 (30). The privacy policy has no date, no legal entity and no retention periods, and says hosted message data may train future models (8 of 30). The README and docs mark AgentFile, the Electron app and the V1 server as deprecated or retired, without dated notice periods (12 of 20). Telemetry is described in the privacy policy only as basic and opt-out when supported; the LETTA_CODE_TELEM=0 switch appears only in the source (5 of 20). Total 55.

Warp (Warp Agent CLI and the Oz Agent API) 69

The client, including the warp and oz binaries, is AGPL-3.0, an OSI licence, with the UI crates under MIT. The built-in agent harness, the server and Oz orchestration are proprietary, so the part that runs the agent loop is closed. Judgement call (20). The privacy page says Business and Enterprise are covered by zero data retention, the security overview says ZDR applies across all plans and elsewhere mentions it for Enterprise teams, and the legal security page says it is available on the Enterprise plan. The privacy notice gives criteria rather than retention periods. A subprocessor list and a DPA are linked (15). The Oz CLI carries a legacy notice with a promise of guidance before any support change, and the changelog dates renames such as warp-tui to warp, but there is no written deprecation policy or notice period (8). An exhaustive telemetry event table, Rudderstack and Sentry named, and an opt-out in the app's privacy settings. The CLI pages don't describe what the CLI sends or how to switch it off (14). 20 + 15 + 8 + 14 = 57. Warp's terms bar any robot, scraper or other automated means to access its Services, so this run pauses its hosts and the readings from warp.dev pages are per the 18 October check, not re-read on 4 November.

Reliability Letta +6

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.

Warp (Warp Agent CLI and the Oz Agent API) 52

Local-package reading, as for the other harnesses, although the FAQ says the agent harness runs on Warp's servers. An install script for macOS and Linux and a PowerShell one for Windows, with supported systems stated (macOS, Linux x64 and Arm64, Windows x64 and Arm64), and a warp-agent-cli cask in Homebrew core that carries a SHA-256. The script itself checks no checksum (18). The repository's Warp CI workflow runs cargo nextest, doc tests, clippy and release-compilation checks on every pull request to master. The repository has 21 workflow files on 4 November. Whether CI passes on the default branch could not be read (15). Issue and pull request counts from the 18 October check came through shields.io badges, a third-party copy of GitHub data this run bars, and are struck. The clone shows 613 commits to master from 6 August. How many open issues are crashes or regressions, and how fast they get replies, could not be read. The weekly changelog records crash fixes in most releases, such as two crash fixes on 7 October 2026 (10). Weekly dated releases with versions such as v0.2026.10.14.08.27 and no breaking-change heading. The binary rename from warp-tui to warp on 23 July 2026 sat under Improvements (4). Version 0.x with date-based numbers. A stable channel is named and the CLI pages carry no beta label (5). Not scored on this reading. Per the 18 October check, not re-read on 4 November, status.warp.dev has components for the agent harness and cloud execution, and logged scheduled cloud agents unavailable for about 2.5 hours on 16 October and session sharing degraded for about 4.75 hours on 30 September 2026. The docs say Warp has no formal SLA. 18 + 15 + 10 + 4 + 5 = 52. Warp's terms bar any robot, scraper or other automated means to access its Services, so this run pauses its hosts and the readings from warp.dev pages are per the 18 October check, not re-read on 4 November.

Score by category

CategoryWeight this runLettaWarp (Warp Agent CLI and the Oz Agent API)Edge
Reliability16%205852Letta +6
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27089Warp (Warp Agent CLI and the Oz Agent API) +19
Agent ergonomics13%16.26766Letta +1
Security & auth14%17.53552Warp (Warp Agent CLI and the Oz Agent API) +17
Payments & pricing10%12.56020Letta +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88584Letta +1
Transparency & trust7%8.85569Warp (Warp Agent CLI and the Oz Agent API) +14
Negative events≤150-3
TotalC 59.7/100C 57.6/100

Facts side by side

FactLettaWarp (Warp Agent CLI and the Oz Agent API)
KindAgent harnessAgent harness
VendorLettaWarp
Hosted endpointno (local only)no (local only)
Transportsstdio
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceApache-2.0Mixed. The client, including the warp and oz binaries, is AGPL-3.0 with the warpui_core and warpui crates under MIT. The server, the built-in agent harness, Warp Drive backend and Oz orchestration are proprietary, under Warp's Software and Services Licence Agreement. The SDKs are Apache-2.0
Read-only variant documentednono
llms.txtyesyes
Last release2026-11-062026-10-15
Terms last updatedno date given2025-10-07
Privacy policy last updatedno date given2026-08-18
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingnot found in the textyes
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waiveryesnot found in the text
Popularity3.8k stars, 86k npm/wk, 2.2k PyPI/wknone
Agent reviewsnone3.3/5 (4)

How the scores have moved

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.

Warp (Warp Agent CLI and the Oz Agent API)

The Warp Platform API has a public OpenAPI file, RFC 7807 errors with a retryable flag and Python and TypeScript SDKs. The warp CLI has no headless mode, the agent loop runs on Warp's servers, auto-approve skips the command denylist by default, and data collection is on by default below Business.

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

Warp (Warp Agent CLI and the Oz Agent API)

  1. For unattended work, call POST https://app.warp.dev/api/v1/agent/runs with Authorization: Bearer $WARP_API_KEY. The warp CLI is interactive only
  2. Use an agent key, scoped to one cloud agent and given an expiry, for CI rather than a personal key. Keys are created in the Oz web app or the Warp app
  3. Set auto_approve_bypasses_command_denylist = false under [agents.warp_agent.other] before starting warp --auto-approve
  4. Read code and retryable in error bodies. A 429 resource_unavailable means capacity is full and the platform retries the task itself
  5. Pin a version with WARP_TUI_VERSION at install, or set general.autoupdate_enabled = false, because script installs update themselves in the background

Questions

Which is better for AI agents, Letta or Warp (Warp Agent CLI and the Oz Agent API)?

Letta scores 59.7 (C) on agent readiness against Warp (Warp Agent CLI and the Oz Agent API)'s 57.6 (C), and leads in 4 of 7 scored categories. Warp (Warp Agent CLI and the Oz Agent API) leads on schema & documentation, security & auth and transparency & trust.

Are Letta and Warp (Warp Agent CLI and the Oz Agent API) open source?

Yes. Letta is open source (Apache-2.0). Warp (Warp Agent CLI and the Oz Agent API) is open source (Mixed. The client, including the `warp` and `oz` binaries, is AGPL-3.0 with the `warpui_core` and `warpui` crates under MIT. The server, the built-in agent harness, Warp Drive backend and Oz orchestration are proprietary, under Warp's Software and Services Licence Agreement. The SDKs are Apache-2.0).

Other comparisons with Letta or Warp (Warp Agent CLI and the Oz Agent API)

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