https://engineering.vectorbea.com Engineering notes from the team building Vectorbea, a durable, long-running visual agentic workflow builder. Execution guarantees, retries, checkpoints, approvals, BYOK, and worker orchestration. en-us https://engineering.vectorbea.com/articles/lessons-from-building-vectorbea-v1 https://engineering.vectorbea.com/articles/lessons-from-building-vectorbea-v1 Tue, 26 May 2026 00:00:00 GMT What we'd keep and what we'd change across UI, backend, security, observability, and positioning, after shipping the first version of Vectorbea's durable workflow engine. Susmit Banerjee lessons retrospective engineering-culture https://engineering.vectorbea.com/articles/self-correction-loops-for-failed-workflows https://engineering.vectorbea.com/articles/self-correction-loops-for-failed-workflows Tue, 05 May 2026 00:00:00 GMT The difference between retrying a failed step and helping a workflow understand why it failed, error classification, bounded self-correction, and where we draw the line and call a human. Susmit Banerjee agentic-systems self-correction reliability https://engineering.vectorbea.com/articles/cost-budgets-and-rate-limits https://engineering.vectorbea.com/articles/cost-budgets-and-rate-limits Tue, 21 Apr 2026 00:00:00 GMT How we estimate token costs before and during a run, enforce per-run and per-workspace budgets, apply rate limits, and build kill switches that actually stop a runaway workflow. Susmit Banerjee cost rate-limiting reliability https://engineering.vectorbea.com/articles/worker-scaling-with-redis-streams https://engineering.vectorbea.com/articles/worker-scaling-with-redis-streams Tue, 07 Apr 2026 00:00:00 GMT How Vectorbea's worker fleet pulls work from Redis Streams, consumer groups, the pending entries list, retry and DLQ handling, and the honest answer to 'why not Kafka?' Susmit Banerjee infrastructure redis workers scaling https://engineering.vectorbea.com/articles/byok-architecture-for-ai-saas https://engineering.vectorbea.com/articles/byok-architecture-for-ai-saas Tue, 24 Mar 2026 00:00:00 GMT Why we let customers bring their own LLM provider keys, what it costs them and us, and the security boundaries we think any BYOK system needs, without the implementation specifics. Susmit Banerjee security byok architecture https://engineering.vectorbea.com/articles/human-approval-gates-in-agentic-systems https://engineering.vectorbea.com/articles/human-approval-gates-in-agentic-systems Mon, 09 Mar 2026 00:00:00 GMT Modeling 'wait for a human' as a first-class workflow step, waiting states, timeouts, escalation, and why the audit trail has to be airtight. Susmit Banerjee agentic-systems human-in-the-loop ux https://engineering.vectorbea.com/articles/retries-resume-and-idempotency https://engineering.vectorbea.com/articles/retries-resume-and-idempotency Wed, 18 Feb 2026 00:00:00 GMT Step-level retries sound simple until you ask what happens when the step already had a side effect. Notes on idempotency keys, resumption, and duplicate tool calls in Vectorbea. Susmit Banerjee reliability idempotency retries https://engineering.vectorbea.com/articles/designing-event-history-for-ai-workflows https://engineering.vectorbea.com/articles/designing-event-history-for-ai-workflows Mon, 02 Feb 2026 00:00:00 GMT How we modeled the append-only event log that backs every Vectorbea run, and why we treat it as the source of truth rather than an audit trail bolted on afterward. Susmit Banerjee event-sourcing architecture observability https://engineering.vectorbea.com/articles/why-long-running-ai-workflows-need-durable-execution https://engineering.vectorbea.com/articles/why-long-running-ai-workflows-need-durable-execution Mon, 12 Jan 2026 00:00:00 GMT Async jobs and retry decorators get you most of the way to a working agent, and then they don't. Here's why we built Vectorbea around durable execution from day one. Susmit Banerjee durable-execution architecture reliability