00 · PREAMBLE
We are building Rensei.
MARK KROPF · FOUNDER · MAY 2026 · REV 2026-06
Rensei was created because AI-driven software engineering should not have to choose between shipping faster and being tethered to a chat window. SWEs should not have to choose between shipping more code and shipping quality code. Engineers should not have to --dangerously-skip-permissions their way to the next promotion or termination.
The job is to close that gap: code an engineer would sign, shipped at fleet velocity, held to the quality bar a regulated team already answers to. That bar does not move for a startup, and it does not move for a bank.
Built on an open-source local fleet runtime, packaged as a managed platform, designed so the same artifact survives procurement and an auditor's review.
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01 · MEASUREMENT
The last mile is measurement
You cannot improve what you cannot measure. The line is older than the AI category by 150 years, and it still names what most agent platforms today get wrong. Most agent-authored work in production rolls the dice on quality, throughput, and cost. That is fine for an experiment. It is not what large enterprises can put real work behind. The demo is not where the value is. The value is the deploy that survives an audit you did not schedule.
On Rensei, output and effectiveness scale together. Volume without measurement is noise. We instrument every workflow, every decision, every token, so the question stops being “did the agent do something” and becomes “did the agent do the right thing, at the right cost, with the right outcome.” That is the last mile. We chose to start there.
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02 · DETERMINISM
Determinism wraps non-determinism
Many platforms in this category start LLM-driven from top to bottom. The control loop is non-deterministic. The audit is impossible. The output is whatever the model returns this run.
Rensei inverts that. The workflow engine is deterministic: durable state, idempotent step boundaries, replayable from any point. LLMs are bounded effectful operators inside steps, not the control loop itself. As the platform matures, we surround the non-deterministic sessions with deeper deterministic rigor. That commitment raises quality and auditability at the same time, and it turns out to be more token-efficient and more performant.
The buyer who wants reliable output and the engineer who wants a tight loop are asking for the same thing.
Because the determinism lives at the workflow layer, the model and sandbox seams stay open: Anthropic, OpenAI, and Google run in production at Rensei today, and the capability matrix documents additional endpoint configurations (Bedrock, Vertex AI, Azure OpenAI, OpenAI-compatible, local). Customers running multiple frontier models, multiple inference vendors, or multiple sandbox environments do not pick one to adopt Rensei. Routing today is policy- and load-aware. Per-line provenance and survival measurement are live; the survival-to-posterior wiring is in active integration and closes during the design-partner phase.
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03 · COMPOSITION
Compose, do not replace
Most agent platforms ask the organization to learn a new chat interface. Adoption stalls because the work was never in the chat window. Product managers write issues, epics, and milestones. Software engineers work in TDD, acceptance criteria, and architectural plans. QA owns test coverage and end-to-end maturity. DevOps and SRE drive DORA metrics and the path to production.
Rensei brings the fleet to those surfaces. We compose with the tools teams already use and with the audit and observability investments those tools already make. Cedar policies, hash-chained audit, and decision provenance bolt into the SOC2 controls and SIEM integrations procurement already credits. Humans and AI work together inside the planning and tracking systems that already run the business.
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04 · THE FLEET
One founder and the fleet
Large organizations have been promised something better than one engineer to one chat window. The open-source projects out there scale individual impact for indie builders. None of them are built for enterprise. None of them ship as a managed platform a buyer can put through procurement.
Rensei is. The platform you are reading about was built by one operator running an agent fleet on the platform itself. The open-source workflow runtime that powers it, Donmai, is the same runtime our customers deploy. We could not have shipped at this velocity without the platform we are selling. The buyer cannot either, on the platforms that exist today.
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05 · REGULATED FIRST
Regulated enterprise first
The carrot in this category is hot new tech: fast-moving, hyperscaling agent workflows the brochure leads with. The procurement speed run is the enterprise rigor built in from the beginning. Most platforms put one in the brochure and pretend the other arrives later. Rensei does both in the same architecture from day one.
The cutting-edge runtime and the procurement-ready trust layer are the same artifact.
The inconvenient truth in regulated industries is that engineers want the newest tools, and the reality of their size and regulatory exposure holds them back. They wait years for the trust layer to catch up to the demo. By the time it does, the demo is old.
Rensei flips that sequence. Cedar policy enforcement, hash-chained tamper-evident audit, fail-closed egress, and decision provenance are how the platform was built from the first commit. Banks, hospitals, clearing houses, and government agencies can evaluate on Monday. That is what we are building.
The runtime this document promises is documented in the platform reference, and every claim it makes carries a status in the claims ledger.
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