LettavsProliferate
Generated from the two spec rows. Green marks the better value where a spec has a clear direction. Everything else is just different.
Letta
Letta · Agent harness
OSS
Panel
6.51 spec wins
- Reliability
- 6.0
- Usefulness
- 6.7
- Cost
- 7.0
- Longevity
- 6.3
“It used to be called MemGPT, and it remembers that.”
Proliferate
Proliferate · Agent harness
OSSMCP
Panel
6.65 spec wins
- Reliability
- 6.3
- Usefulness
- 7.0
- Cost
- 7.2
- Longevity
- 6.0
“It can run your dependency bumps nightly, so now the robots have a shift and you have a merge queue.”
Spec by spec
| Spec | Letta | Proliferate |
|---|---|---|
| Architecture | ||
| Category | Agent harness | Agent harness |
| Runs | local, cloud | local, cloud |
| Platforms | macos, linux, windows, web | macos |
| Context window | not documented | not documented |
| Protocols | ||
| MCP client | No | Yes |
| MCP server | No | No |
| Capabilities | ||
| Runs terminal commands | Yes | Yes |
| Multi-file edits | Yes | Yes |
| Git operations | No | Yes |
| Browser control | No | YesBrowser Use and Computer Use are listed among the integrations shared across agents. |
| Sandboxed execution | No | No |
| Multi-agent orchestration | No | YesAgents run side by side on separate tasks and can also delegate to child subagents within a task. |
| Headless / CI mode | No | No |
| Models | ||
| Backbone | any | via managed agents (Claude Code, Codex, OpenCode, Cursor, Grok) |
| Bring your own model | Yes | Yes |
| Local models | No | No |
| Cost | ||
| Pricing model | mixed | byok |
| Starts at | $20/mo | $0/mo |
| Free tier | Yes | Yes |
| Bring your own key | Yes | Yes |
| Openness | ||
| Open source | Yes | Yes |
| License | Apache-2.0 | AGPL-3.0 |
| GitHub stars | 25,000 | 511 |
Which one would each critic pick
| Critic | Letta | Proliferate | Pick |
|---|---|---|---|
| El Juez | — | — | not enough reviews |
| El Amigo | 6.5 | 7.3 | Proliferate — Pick it if you want several agents working at once and each behaving exactly as its own CLI does; pick Warren if the runs belong on a server rather than your laptop. |
| El Crítico | 6.0 | 6.3 | Proliferate — Workflows schedule recurring and event-driven runs, and those agents execute on your machine with no container boundary documented anywhere around them. |
| El Profesor | 6.8 | 7.0 | Proliferate — Tools, skills and servers are configured once and shared by every agent, so behaviour differences between five harnesses are attributable to the harnesses rather than to their setup. |
| La Inversora | 6.5 | 6.0 | Letta — The free plan caps you at three stateful agents, which is a well-drawn funnel: the limit bites exactly when the product has started to be worth paying for. |
| La Jefa | 6.0 | 5.5 | Letta — Twenty dollars a seat is $1,200 a month for sixty, which is fine, but nothing on the page describes single sign-on, audit trails or where the memory is retained. |
| El Hacker | 7.3 | 7.8 | Proliferate — AGPL-3.0, an MCP client, and Computer Use and Browser Use shared across every agent, with my own keys and subscriptions doing the paying. |
Picks are derived from each critic's own scores. Humans vote on matchups on the duels page.