Droid CLI vs Letta

Droid CLI 10

Harness reading of the published rubric. This is paid, closed software tied to a subscription, so the self-hosted rule does not apply. No payment protocol (0). Plan prices are public, $20, $100 and $200 a month for individuals and $60 a team plus $40 a seat for Teams, but included usage is given only as rolling rate limits and multiples of Pro (10). No free tier or trial was found on the pricing pages. Using your own model key is free up to an allowance, but only on a paid plan (0). A person signs in through a browser to subscribe and to create the API key. The Service Accounts API can issue keys only inside an existing organisation (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.

Droid CLI 63

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 prompt-injection posture, 15 for audit and 20 for the security programme. The agent loop runs locally and the docs say no copy of the repository is uploaded or indexed. Prompts and context go to the model endpoints. Usage metrics go to Factory's collector by default, with no opt-out in the pages read outside an airgapped deployment, and message content is never sent to it. The security page says code is not used as training data. Zero data retention is listed as a Business plan item. Headless runs use a long-lived fk- key (17). droid exec is read-only by default, autonomy has four levels, permission rules allow, ask or block commands, and an OS sandbox confines commands with Seatbelt or bubblewrap and a network proxy. The sandbox is off by default and --skip-permissions-unsafe skips every prompt (16). The sandbox page names prompt injection and states what the sandbox does not stop, MCP approvals are bound to the server's command or URL, and Droid Shield scans commits for secrets. The Agent Safety page was not read (9). An organisation audit log, OpenTelemetry export and session tags exist, with audit logging listed from the Business plan up (10). A disclosure address (security@factory.com), SOC 2 and ISO 42001 named on the security page, per the 9 October check, and Security sections in the changelog. No security.txt (404 on 4 November), no bug bounty and no published advisories were found, OSV holds nothing for droid, and the trust centre was not readable (11).

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.

Droid CLI 65

Closed source under terms from The San Francisco AI Factory, Inc., last updated 14 July 2026. The npm package is marked UNLICENSED and the Python SDK is Apache-2.0 (15). The Data Flows page says where code, prompts and telemetry go in each deployment pattern, and the privacy policy (20 August 2026) lists service providers with the place of processing and keeps personal data up to 10 years after last use. Retention of Factory's operational logs is left to the trust centre, which we could not read, and whether session transcripts are stored in Factory's cloud on individual plans was not established (17). The terms promise commercially reasonable efforts to give 60 days' notice of major changes, the changelog has Deprecations sections, and the old command lists are deprecated but still honoured. A model retirement appeared in the changelog on the day it took effect, 11 August 2026 (12). The telemetry reference documents each metric and what reaches Factory, and telemetry.granularity can strip user identity. Metrics to Factory are on by default, with no opt-out found outside an airgapped deployment (11).

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.

Droid CLI 79

Framework reading. The docs index links an OpenAPI file for the Factory public API, which we did not open, and the headless mode has a documented JSON-RPC surface with named methods. droid exec --list-tools --output-format json and droid rules check --json give machine-readable output. We found no published schema for the settings file (15). docs.factory.com/llms.txt lists a Markdown copy of every page (10). The overview says when to use the CLI, and the autonomy table says what each level allows, blocks and suits (16). Autonomy levels, output formats, sandbox modes and MCP server fields are enumerated with types and defaults (12). Examples on every page read, exit codes 0, 1 and 2, and a JSON result with is_error and subtype, with no error catalogue (11). A changelog by CLI version with dates and an RSS feed, 236 entries back to 30 September 2025 (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.

Droid CLI 79

The changelog's newest entry is CLI v1.3.0 of 4 November 2026 (30). 67 dated changelog entries between 6 August and 4 November 2026, 20 of them after 9 October (20). The public tracker had 33 open issues that are not pull requests on 9 October 2026, most with no reply, and three closed in the previous week after two or three comments, not re-read on 4 November. Support is also by email and Discord, where reply times are not visible (9). The TypeScript SDK repository moved to 0.10.0 with examples tested in CI on 20 October 2026, and the Python SDK is at 0.5.0 of 24 September 2026 (15). The npm package is published from GitHub Actions through a trusted publisher and the installer checks a checksum, per the 9 October check. There is no public CI for the CLI (5).

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.

Droid CLI 72

Harness reading of the framework line. --restrict-tools, --disabled-tools, --additional-tools and --list-tools control built-in tools per run, and disabledTools in mcp.json keeps named MCP tools out of context. We found nothing on deferred tool loading (18). Output is text, json, stream-json or stream-jsonrpc, and the JSON result carries turns and duration. The droid exec help lists no flag for a turn or spend limit (10). Exit codes 0, 1 and 2 are documented, and a run that exceeds its autonomy level stops with a non-zero code and no partial changes, per the docs (15). --session-id continues a session, --fork branches one, and --worktree isolates parallel runs (16). Headless runs are read-only without flags, and TypeScript and Python SDKs wrap the CLI. A run needs a paid Factory account and an API key (13).

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.