# Emdash vs Letta

> Letta scores 59.7 (C) to Emdash's 53.9 (D) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/emdash-vs-letta
- Markdown: https://www.anchorterminal.com/compare/emdash-vs-letta.md (~4,450 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Letta scores 59.7 (C) on agent readiness against Emdash's 53.9 (D), and leads in 5 of 7 scored categories. Both do agent harnesses.

- Emdash: grade D, 53.9/100, rank #933 of 1510. Markdown https://www.anchorterminal.com/tools/emdash.md · JSON https://www.anchorterminal.com/api/v1/tools/emdash.json
- Letta: grade C, 59.7/100, rank #687 of 1510. Markdown https://www.anchorterminal.com/tools/letta.md · JSON https://www.anchorterminal.com/api/v1/tools/letta.json
- Best agent harnesses and coding agents: https://www.anchorterminal.com/best/agent-harnesses/index.md
- All 1500 harnesses comparisons: https://www.anchorterminal.com/compare/agent-harnesses/index.md
- Best memory layers for AI agents: https://www.anchorterminal.com/best/agent-memory/index.md
- All 353 memory comparisons: https://www.anchorterminal.com/compare/agent-memory/index.md

## Which one, for what

### Emdash (D)

Good for: Developers who want parallel agents in worktrees, fed from their issue tracker, locally or over SSH.

Also in its favour:
- No key needed to call it

Watch for: Telemetry on unless turned off in Settings or with TELEMETRY_ENABLED=false

### Letta (C)

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

Ahead on:
- Schema & documentation, 70 against 55
- Agent ergonomics, 67 against 55
- Maintenance & community, 85 against 70

Also in its favour:
- Runs on your own machine

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

### Schema & documentation: Letta +15

- Emdash (55): Harness reading. Docs site and a workspace server package (55).
- 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.

### Maintenance & community: Letta +15

- Emdash (70): v1.2.11 on 6 November 2026 (30). v1.2.9, v1.2.10 and v1.2.11 within two weeks (20). GitHub issues and pull requests weren't read (GitHub's pages refuse these sessions), so that line is scored absent (0). Current installers and Homebrew cask (15). Release workflows, no test CI (5). 30 + 20 + 0 + 15 + 5 = 70.
- 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

- Emdash (55): Harness reading. Issue intake from Linear, GitHub, Jira and others, diff review, pull requests and CI checks in one place, local or over SSH (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.

## Score by category

| Category | Weight | Emdash | Letta | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 58 | Letta +3 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 55 | 70 | Letta +15 |
| Agent ergonomics | 13% (16.2 this run) | 55 | 67 | Letta +12 |
| Security & auth | 14% (17.5 this run) | 38 | 35 | Emdash +3 |
| Payments & pricing | 10% (12.5 this run) | 60 | 60 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 70 | 85 | Letta +15 |
| Transparency & trust | 7% (8.8 this run) | 54 | 55 | Letta +1 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **53.9 · D** | **59.7 · C** | |

## Facts side by side

| Fact | Emdash | Letta |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | General Action, Inc. | Letta |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  | stdio |
| Auth | None | OAuth or key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-11-06 | 2026-11-06 |
| Terms last updated | no document linked | no date given |
| Privacy policy last updated | no document linked | 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

**Emdash.** A mature open-source app for parallel coding agents in Git worktrees, with issue intake from a dozen trackers and remote machines over SSH. Telemetry is on unless you turn it off, and no test workflow was found in the repository.

**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

### Emdash

1. Launch with TELEMETRY_ENABLED=false if you don't want telemetry
2. Use the SSH mode to keep agents on a remote machine

### 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, Emdash or Letta?

Letta scores 59.7 (C) on agent readiness against Emdash's 53.9 (D), and leads in 5 of 7 scored categories.

### Are Emdash and Letta open source?

Yes. Emdash is open source (Apache-2.0). Letta is open source (Apache-2.0).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/emdash-vs-letta.json, and with the fewest tokens: https://www.anchorterminal.com/compare/emdash-vs-letta.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "emdash", "b": "letta"}`. From a terminal: `anchor compare emdash letta`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/emdash.json and https://www.anchorterminal.com/api/v1/tools/letta.json

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp