Case Study: 3 AI Agent Apps in One Day

This case study documents a one-day sprint inside the 10K MRR experiment where I directed AI agents to ship three app foundations in parallel.

The point was not to produce perfect products in a day. The point was to validate whether one operator, with strict orchestration, could generate small-team output without losing build quality.

Context

Days 1-3 established operating rhythm, but there was still no product surface for users. On February 4, the priority changed from setup to shipping.

The objective for the day:

• launch three distinct product foundations
• keep each build production-structured
• avoid cross-repo coordination drag

The three products

AgentPersonalities

A marketplace for SOUL.md personality files with upload, browse, and remix flows.

PromptDuels

A head-to-head prompt battle workflow with ELO-style rankings and side-by-side comparisons.

TaskBounty

A task marketplace with points-based prioritization and reputation-oriented completion flow.

Build system

The day was managed with a strict process:

1. Specs before execution Each app received a constrained spec: data model, routes, auth expectations, and core user loop.

2. Parallel agents Three coding streams ran concurrently, each scoped to one repo.

3. Frequent commit checkpoints Agents committed every 10-15 minutes to reduce loss from timeouts and simplify review.

4. Hardening pass Late-day pass focused on auth edges, loading states, and error handling.

5. Build gate No app counted as shipped unless the build passed cleanly.

What worked

Spec quality drove output quality

The best velocity gain came from clear constraints and explicit acceptance criteria. Where specs were vague, agents drifted.

Parallelism outperformed sequential delivery

Independent streams eliminated waiting time. While one app was resolving auth edge cases, others continued shipping features.

Small commits reduced risk

Timeout recovery stayed manageable because the work was already checkpointed in small units.

What failed

Provisioning friction

Some backend setup tasks remained manual and slowed otherwise automated flow.

Large mixed-concern refactors

Agents were strongest on bounded tasks and weaker when asked to change auth, data, and UI layers in one step.

Deployment lag

Green builds were achieved, but deployment and user validation still required follow-through. Shipping code and shipping value are different phases.

Outcome

The sprint confirmed that agentic delivery can generate high-volume implementation output in a single day when orchestration is disciplined.

It also confirmed that the bottleneck moves quickly from coding to deployment, distribution, and user feedback.

For the broader experiment context, see /experiment/10k-mrr. For the related narrative post, see I Launched 3 AI Agent Apps in One Day With Zero Lines of Code.