Where this repository stands — 2026-10-08. This is the organisation's most-starred repository and its monorepo: the Agent SDK plugin, the ai-os subtree, the packages/ and the 2025 toolkit. It is not where the lab's current work happens. The flagship since 2026-09-19 is lora-kernel, and agentvcs was revived as its own repository on 2026-10-06 — packages/agentvcs/ here is a frozen copy.

The history, in order: frozen on 2026-08-01 with a pointer to ai-os; active again on 2026-09-06 when ai-os came home as a subtree, history intact; the subtree has not changed since that day.

Nothing was rewritten to make the arrival look tidy. The 2025 toolkit stays in legacy/eat/, the flat results stay in Evidence below, and two more have been added — because they point the same way as the first, which is the finding.

The loop is solved. What happens after the fork is not.

A plugin for the Claude Agent SDK that versions an agent's evolution — diff it, merge it, refuse to ship it when the eval fails.

Twenty-five more repositories are archived and read-only; each is listed, with where it moved, at evolvingagentslabs.github.io/archive.

The Agent SDK runs the loop, ships the tools, manages context, and enforces permissions. It also branches: fork gives you a second session starting from a copy of the first.

Nothing brings the two back together. There is no merge, no diff between two sessions, nothing that refuses to promote an agent whose eval regressed, and the transcript is plain JSONL that anyone can edit. Sessions persist the conversation — the skills, subagents, model and goal that produced it are not versioned alongside it.

That gap is this repository. Most of it is closed; the last row is not, and it is the one worth being precise about.

The unit avcs_diff and avcs_merge operate on is an agentvcs commit, not an SDK session. Both work today, and neither will take two session IDs: a session is an append-only event log, and the adapter that turns one into something mergeable does not exist yet. Two forked sessions do share a prefix, so the common ancestor is findable — the open question is what a conflict means when both branches are conversations that reached different conclusions about the same file.

That adapter is M1, it has not started, and it is the reason this repository exists rather than a detail of it.

from claude_agent_sdk import query, ClaudeAgentOptions

options = ClaudeAgentOptions(
    plugins=[{"type": "local", "path": "/path/to/evolving-agents/plugin"}],
)

Full details in plugin/README.md. The MCP server has zero runtime dependencies — standard library only, with a test that fails if that ever stops being true.

It was the Evolving Agents Toolkit: 18,680 lines across twelve subsystems — a component library, an agent bus, smart memory, an evolution loop, and a governance layer called Firmware. Backed by MongoDB Atlas.

It had three test functions.

That number is the story. EAT was not a product that failed; it was an architecture written down and never pinned to anything that could contradict it.

Most of it is now deleted, because the SDK does it better — docs/WHAT-WAS-DELETED.md lists the 10,165 lines and what replaced each one. Firmware asked a model to "never use dangerous imports" in a string; a PreToolUse hook returning permissionDecision: "deny" stops the call whatever the model decided. We do not ship our own version of a problem that is already solved.

What survives in legacy/eat/ is the ancestry of what ships today. Read evolution/ if you read one thing: 337 lines that closed the loop between an agent changing and that change being kept, with nothing to verify the change was an improvement. avcs_freeze is the same idea with the missing half added.

Claims here are measured, including the ones that came back flat.

• The dual-embedding resolver does not help. EAT indexed every component twice — once for what it is, once for what it is for. Rebuilt and measured: 80% acc@1 either way, no difference. The second axis is genuinely distinct (cosine = 0.753); it just buys nothing on a modern encoder.
• This organisation's "byte-identical wire format" claim was wrong. Two of three opcode regexes matched; HALT had diverged in a way that changes what parses. Found by writing the test instead of repeating the sentence.
• Retrieving past experience buys nothing on the task. EAT's SmartMemory and its ContextBuilderTool rest on the premise that recalling similar past work improves the next attempt. Measured three times in ai-os and the runtime beside it: −4 against a retriever handed the solved similar cases with their answers, +0 (p = 1.0000) against the strongest retriever constructible, and −6 against an oracle retriever — below doing nothing. What did move was a compact statement of a rule induced from the same trajectories: +21 over the oracle.
• The memory hierarchy loses to lexical search. ai-storage implements the four levels EAT's smart memory argued for. Its first benchmark, at the ceiling with a perfect navigator: exact search 3/3 at every corpus size, hierarchical navigation 1–2/3 and out of steps, the flat file refusing to fit at all.

Three flat results, three architectures, one direction. The dual axis in 2025, the experience retrieval in 2026, the hierarchy after it. Each was the obvious next structure and each was asked for a number. That is what this repository is for, and it is why the toolkit is in legacy/ rather than deleted: it was right about where to look and wrong about what would be there.

pip install git+https://github.com/EvolvingAgentsLabs/evolving-agents no longer installs an evolving_agents package — this is a monorepo now. Install what you want by name:

agentvcs was never published to PyPI — the release workflow exists but its Trusted Publisher was never registered, so pip install agentvcs returns 404. Install the frozen copy from source:

pip install "git+https://github.com/EvolvingAgentsLabs/evolving-agents#subdirectory=packages/agentvcs"

The maintained agentvcs is EvolvingAgentsLabs/agentvcs (Rust runtime and its Python SDK; build instructions in its README).

The 2025 package sits at legacy/eat/ with its original setup.py, unchanged.

_{By Matias Molinas and Ismael Faro · Apache 2.0}