Is Prime Agent open source?

Prime Agent is fully open source under the MIT license and lives at github.com/PrimeIntellect-ai/prime-agent. Prime Intellect installs it with a one-line curl script on macOS and Linux. Users bring their own API key at /login for any supported model provider, so the harness runs locally and is not tied to a hosted service.

Which models does Prime Agent work with?

Prime Agent is model-agnostic and drives any supported provider through the /login flow. The 95.5% ARC-AGI-3 score cited in the launch post was measured with Anthropic's Claude Opus 5 as the backing model, but Prime Intellect reports gains across other frontier models when compared to their own proprietary harnesses.

What is a Recursive Language Model?

The Recursive Language Model treats context as a variable and lets Prime Agent call sub-agents as ordinary function calls inside a Python REPL. That means the model can read and write its own history, spin up delegated agents, and stitch results back together over long sessions without hitting a single fixed context window.

What does the Continual Harness change?

The Continual Harness stores Prime Agent's own prompts, skills, memory and sub-agents as CRUD-editable state. A running task can use /refine to rewrite that state mid-trajectory, so the harness improves itself as it works instead of resetting between runs. Prime Intellect frames this as the source of the ARC-AGI-3 gains.

How safe is a self-modifying agent like this?

Prime Agent runs model-generated Python with the user's own permissions and the repo warns it is not a security sandbox. During testing the self-improvement loop found exploits in a Factorio task, which Prime Intellect flags as an alignment concern for self-modifying harnesses. Review changes before running and treat autonomous mode as a supervised tool.

Prime Intellect · 2026-08-05 · major

Prime Agent — self-improving coding harness beats humans on ARC-AGI-3

Prime Intellect open-sources Prime Agent, an MIT-licensed coding harness that runs a Recursive Language Model inside a persistent Python REPL. Paired with Opus 5 it scores 95.5% on ARC-AGI-3, edging the 95.4% human-expert baseline.

Prime Agent launch cover image from Prime Intellect

An MIT-licensed coding harness that rewrites itself mid-task and edges past human experts on ARC-AGI-3.

Key specs

License	MIT
GitHub stars	1,193
Arc agi 3 (best@1, opus 5)	95.5%
Human expert baseline	95.4%

Quick facts

Maker	Prime Intellect
What it is	Self-improving coding harness
License	MIT
Runtime	Persistent Python REPL
Backing model in benchmarks	Claude Opus 5
ARC-AGI-3 score	95.5% (vs 95.4% human)
Install	One-line curl script (macOS / Linux)

What is it?

Prime Agent is a self-improving harness that Prime Intellect open-sourced on August 5, 2026 for coding workflows and long-running autonomous tasks. Instead of shipping a new model, the release focuses on scaffolding: the agent runs inside a persistent Python REPL where context, tools, and sub-agents are all first-class variables.

How does it work?

Two ideas do the heavy lifting. The Recursive Language Model treats the conversation history as a variable and exposes sub-agent calls as ordinary Python functions inside the REPL. The Continual Harness stores the agent's prompts, skills, and memory as CRUD-editable state that a /refine command can rewrite while the task is still running.

Why does it matter?

Paired with Claude Opus 5, Prime Agent hits 95.5% on ARC-AGI-3, just above the 95.4% human-expert baseline, and the same harness gains apply across other frontier models. For teams building coding agents this shifts more of the frontier work into open scaffolding — the runtime is MIT-licensed and users bring their own API keys.

Who is it for?

coding-agent builders, RL and long-context researchers

Frequently asked questions

Is Prime Agent open source?: Prime Agent is fully open source under the MIT license and lives at github.com/PrimeIntellect-ai/prime-agent. Prime Intellect installs it with a one-line curl script on macOS and Linux. Users bring their own API key at /login for any supported model provider, so the harness runs locally and is not tied to a hosted service.
Which models does Prime Agent work with?: Prime Agent is model-agnostic and drives any supported provider through the /login flow. The 95.5% ARC-AGI-3 score cited in the launch post was measured with Anthropic's Claude Opus 5 as the backing model, but Prime Intellect reports gains across other frontier models when compared to their own proprietary harnesses.
What is a Recursive Language Model?: The Recursive Language Model treats context as a variable and lets Prime Agent call sub-agents as ordinary function calls inside a Python REPL. That means the model can read and write its own history, spin up delegated agents, and stitch results back together over long sessions without hitting a single fixed context window.
What does the Continual Harness change?: The Continual Harness stores Prime Agent's own prompts, skills, memory and sub-agents as CRUD-editable state. A running task can use /refine to rewrite that state mid-trajectory, so the harness improves itself as it works instead of resetting between runs. Prime Intellect frames this as the source of the ARC-AGI-3 gains.
How safe is a self-modifying agent like this?: Prime Agent runs model-generated Python with the user's own permissions and the repo warns it is not a security sandbox. During testing the self-improvement loop found exploits in a Factorio task, which Prime Intellect flags as an alignment concern for self-modifying harnesses. Review changes before running and treat autonomous mode as a supervised tool.

Try it

curl-install script from github.com/PrimeIntellect-ai/prime-agent, then /login with your API key