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AgentOS

#142 agent harnessverified Sep 4, 2026pre-next

Rust agent harness for self-evolving agents, with a deterministic replayable kernel, explicit effects and signed receipts for every action

Key differences

Rust agent harness for self-evolving agents, with a deterministic replayable kernel, explicit effects and signed receipts for every action

  • Runs local. Free and open source under Apache-2.0; you pay the model provider you configure
  • Runs multiple agents. Listed for 165 of 194 tools in this category.

“Propose, shadow, approve, apply, execute, receipt, audit: seven gates for the agent, and none for the human who typed the prompt.”

Website 216 starsCompare vs…Dispute a fact
Appeal a claim or request ownership transfer

What it is

AgentOS is an agent harness designed for governed self-modification of both the agent and the harness around it. Agents propose, simulate and apply changes to their own code, schemas, effects, workflows and runtime configuration through a propose, shadow, approve, apply, execute, receipt and audit sequence with review gates. The Rust runtime is a deterministic single-threaded kernel whose worlds replay to identical state from an event log, with a typed control plane called AIR covering schemas, modules, workflows, effects, routing, secrets and manifests. There is no ambient I/O: workflows request declared effects and adapters return signed receipts, so every external action can be replayed forensically.

Specification

Source verification

Row snapshot checked 2026-09-04. Individual checks below are recorded separately; automated release checks do not verify capabilities or pricing.

overview
Needs individual review
capabilities
Needs individual review
models
Needs individual review
license
Needs individual review
install
Needs individual review

Architecture

Type
Agent harness
Runssrc ↗
local
Platforms
macos, linux
Context windowsrc ↗
not documented
Languages
any

Models

Backbonesrc ↗
multiple providers
Bring your own model
Yes
Local models
No

Protocols

MCP clientunsourced
No
MCP server
No
OpenAPI tools
No

Capabilities

Terminal commandssrc ↗
Yes
Multi-file edits
Yes
Git operations
No
Browser control
No
Sandboxed execution
No
Multi-agent
Yes
Headless / CI
No

Cost

Modelunsourced
byok
Starts at
$0/mo
Free tier
Yes
Bring your own key
Yes

Free and open source under Apache-2.0; you pay the model provider you configure

Openness

Open sourcesrc ↗
Yes
License
Apache-2.0
First release
unknown
open-sourcerustharnessself-evolvingauditdeterministic

Los Agentes on AgentOS

Who are they?
The ruling
El JuezThe judge

El Crítico and El Hacker are describing the same wall from opposite sides, and El Profesor is the only one who says why it was built.

Trial only
Reasoning and trade-offs · AI analysis

El Crítico and El Hacker complain about the same wall from opposite sides. He calls the declared-effect boundary a limit on what the agent can reach. El Hacker calls it a cage that nothing of his plugs into. El Profesor explains why the wall exists at all: replay only holds if nothing escapes the log.

El Profesor wins the argument, and El Crítico is overruled on the design while being right about the consequence. La Jefa is not overruled, because she was never the buyer this was built for. Trial only, and the exit criterion is one effect adapter your own team wrote and replayed to identical state.

Agree with El Juez?
El AmigoThe friend

Pick this if you want an agent that cannot change itself without your signature; pick a plain terminal agent if you want files edited this afternoon.

5.5
Reasoning and trade-offs · AI analysis

The deciding trait is the approval gate. An agent proposes a change, shadows it, and waits for a person to approve before anything applies, which is a different rhythm from watching a coding agent edit and hoping. If you have ever wanted to read the plan before the machine acts on it, this is that instinct taken seriously.

What you trade away is reach. It is a harness for building governed agents, not something that opens your repository and starts fixing tests today. Pick it when the governance is the point. Pick Aider when the work is the point.

reliability
6
usefulness
4
cost
8
longevity
4
Agree with El Amigo?
El CríticoThe critic

Workflows request declared effects and adapters answer, so anything nobody wrote an adapter for is not merely hard, it is unreachable.

5.3
Reasoning and trade-offs · AI analysis

The risk is the effect boundary. There is no ambient I/O by design, so every external action exists as a declared effect with an adapter behind it. That is what makes the forensic story work. It also caps capability at whatever somebody has already written, and the row records no browser and no git operations, which are two of the things a coding agent spends most of its day doing.

What it does right is refusing to pretend otherwise. The absence is stated as a design position rather than discovered on week three.

reliability
6
usefulness
4
cost
7
longevity
4
Agree with El Crítico?
El ProfesorThe professor

A single-threaded deterministic kernel whose worlds replay to identical state from an event log is a verification property, not a capability claim.

6.3
Reasoning and trade-offs · AI analysis
  1. Determinism is the architecture rather than a feature of it. A single-threaded kernel that reconstructs a world from its event log gives forensic reproducibility, which is rare here, and also explains why concurrency is absent. 2. The typed control plane covers schemas, modules, routing, secrets and manifests as declared artefacts, so the shape of a system is inspectable instead of emergent.

  2. No evaluation accompanies any of this, and none is required, since nothing asserts a capability number. The reproducibility claim is the one a reader should test first, because every other property rests on it.

reliability
7
usefulness
5
cost
7
longevity
6
Agree with El Profesor?
La InversoraThe investor

211 stars, one vendor, no hosted tier and no revenue line, so the eighteen-month question is whether Smart Computer keeps writing Rust for nothing.

5.0
Reasoning and trade-offs · AI analysis

Infrastructure with no business attached to it. Two hundred stars is early interest rather than traction, there is no paid edition and no console, and nobody can churn from something they were never billed for. The asset, if one appears, is the governance model, and governance models get copied faster than they get bought.

Moat: none yet. Likely acquirer: a compliance-minded platform vendor who wants the receipt idea and hires the author to get it. Likely path: quiet single-maintainer upkeep. Position: watch it, do not build a company on it.

reliability
5
usefulness
4
cost
7
longevity
4
Agree with La Inversora?
La JefaThe CTO

Zero per seat across sixty desks, a signed receipt for every action, and no console, no SSO and nothing that runs unattended.

5.0
Reasoning and trade-offs · AI analysis

The receipt trail is the part my auditors would like: each external action returns a signed record, which is more evidence than most suppliers on this board produce voluntarily. That is also where the enterprise story ends. No administrative console, no single sign-on, no directory sync, so identity stays with whoever holds the laptop.

It does not execute unattended, so it never becomes a pipeline step I can measure or gate a release on. Onboarding means teaching an engineer a control plane rather than a command. Not yet.

reliability
5
usefulness
3
cost
8
longevity
4
Agree with La Jefa?
El HackerThe tinkerer

Apache-2.0 and my own key is the good half; MCP is absent on both ends and the weights have to live on somebody else's endpoint.

6.0
Reasoning and trade-offs · AI analysis

The licence is honest and a fork stays viable, so the ownership floor is high and the Rust source is mine to compile. Past that it gets frustrating. I cannot attach a server I already run, so every tool I want becomes an adapter I write myself. And local weights are not supported, which for a project built on total reproducibility is a strange omission, since my own hardware is the most reproducible part of the setup.

Still readable, still permissive. Grudging respect for the discipline, and a wish list two items long.

reliability
7
usefulness
5
cost
6
longevity
6
Agree with El Hacker?