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Coding agent (CLI) · Prime Intellect

Prime Agent

Rust coding and research agent built around a persistent Python REPL where subagents are function calls; sessions run in a background daemon, can be reattached, and refine their own harness state.

Reviewed by the Termdex team · facts checked 2026-10-28 against 4 vendor sources · how we check

Official site

Prime Agent review

Prime Agent is a Rust coding and research agent from Prime Intellect, built around a persistent Python REPL. The tool is free and MIT licensed. We read the vendor's repository in October 2026. We did not run an independent test.

Who it is for

Researchers and power users who want long-running, programmable agents with subagents and a persistent Python environment. It is not for anyone who needs a sandbox out of the box.

What stands out

Subagents are function calls in the REPL (`rlm.spawn`), for parallel or background work. Agents can message one another. Sessions run in a background daemon, so they survive terminal disconnects and can be reattached. The README also describes schedules, persistent goals and a bounded autonomous mode.

The CLI has a `-p` print mode and json, rpc and acp output modes, so it can be scripted. We took this from the CLI source, not prose docs. It includes an MCP client. At `/login` you choose a subscription or your own API key. Install is a one-line shell script.

Price and licence

The tool is free, as of 28 October 2026. The licence is MIT, with copyright to Prime Intellect Ltd. An appended note says it is a port of a TypeScript product by Mario Zechner. GitHub shows "Other" only because of that extra credit paragraph. Model cost comes from the provider you pick at login.

Where it falls short

Alternatives

See terminal coding agents. pi is a smaller MIT-licensed agent, and OpenCode is a general open-source option.

Facts: platforms, price and licence

platforms
macOSLinuxWindowsOne-line installer for Unix shells plus a PowerShell installer for Windows x64 (README). macOS and Linux are named in the changelog (kqueue/pidfd daemon code); the README does not list platforms explicitly. Rust rewrite of an earlier TypeScript version.
price
FreeTool is free and MIT licensed (seen 2026-10-28). Model cost comes from the provider you pick at /login: a subscription or your own API key.
source
Open sourceLicence: MIT
github
PrimeIntellect-ai/prime-agent 22.4k stars, seen 2026-10-28

Prime Agent features

✓ documented · – absent or not in its feature list · ? not verified

Prime Agent strengths

  • Built-in subagents (rlm.spawn) for parallel or background work, and agents can message one another
  • Daemon-backed sessions survive terminal disconnects, with heartbeats, schedules, persistent goals and a bounded autonomous mode
  • Print mode and json/rpc/acp output modes in the CLI make it scriptable
  • MIT licensed, Rust binary, frequent releases from a known lab

Prime Agent weak points

  • README states it is not a security sandbox: model-generated Python and commands run with your user permissions
  • Documentation is thin; the docs folder holds only a Slack MCP guide and release notes, so model and local-model support are not documented
  • Young project (repo created May 2026) and a Rust port of an earlier TypeScript version, so behaviour may still shift
  • Oriented to research and long-running evaluation work, with an unusual REPL-centric workflow

Who Prime Agent is for

best for
Researchers and power users who want long-running, programmable agents with subagents and a persistent Python environment.
look elsewhere if
Anyone who needs a sandboxed agent out of the box or a well-documented list of supported models.

Lists that include Prime Agent

Sources and what we could not verify

Checked 2026-10-28. Prices and features change; the vendor's page is the authority.

Not verified