Diagrams that map to code
Eraser and Whimsical render pretty boxes; your engineers still build whatever fits the deadline. Bob's diagrams become the file structure and module boundaries Alex actually uses in the codebase.
Bob·ArchitectAI Architect Agent that designs systems your team builds
Bob draws the system, picks the stack, and hands the structure to Alex so your architecture becomes the codebase, not a forgotten doc.
Diagrams that map to code, not pretty pictures.
Trusted by builders at
Why architecture docs go stale the day they are written
Pretty diagrams nobody implements
Eraser and Whimsical render beautiful boxes and arrows. Your engineers still build whatever fits the deadline. Bob's diagrams become the file structure and module boundaries Alex actually uses.
Stack choices made by trend
"We picked Mongo because it was popular." Bob explains why Postgres over Mongo, why a queue over direct calls, why Redis vs Memcached. The reasoning is in writing so you can challenge it.
Architecture and code drift apart
The wiki diagram is from sprint 1. The code is from sprint 14. Nobody updates either to match. Bob reviews the current system and updates the architecture doc to reflect what is actually shipped.
Non-functional needs caught after launch
Performance, security, and observability get retrofitted after the first outage. Bob plans them during design with Emma's scale requirements and the access patterns your data model needs to support.
A day with Bob
From your first prompt to a shipped result — here is how Bob actually works.
- 01
Read Emma's PRD
Bob starts from a bounded scope so the architecture matches the product, not the other way around.
Hand-off to Emma - 02
Choose the stack with reasoning
Database, framework, queue, cache — each pick comes with a written trade-off you can challenge.
- 03
Map data models and module boundaries
Entities, relationships, ownership, write paths — the things that hurt to refactor later.
- 04
Draw the system diagram that maps to code
Boxes and arrows mirror real modules and dependencies; the diagram stays in sync as code lands.
- 05
Hand the structure to Alex
Alex builds inside the boundaries Bob drew — no "we will refactor in three months" tech debt baked in.
Hand-off to Alex
Everything Bob needs to design solid systems
Architecture diagrams
Service, data flow, and integration diagrams generated in the Editor, not in a separate tool.
Tech stack recommendations
Stack choices justified against your constraints, not picked by trend or familiarity.
Data model design
Schemas and relationships designed for the actual access patterns of your product.
Non-functional planning
Performance, security, and observability addressed during design, not after launch.
Decision logs
Architectural decisions written down with reasoning so future-you can revisit them.
Structure-to-code mapping
Diagrams map to the file structure and module boundaries Alex builds with.
Architecture review
Bob can review existing systems and recommend changes with clear reasoning.
What changes when Bob is on your team
Hand-rolled workflows are slow, manual, and tool-heavy. Hover any card to see why each gain matters.
Why builders pick Bob over the rest
Compare vs
Coming from Eraser AI? Here is where Bob pulls ahead.
Stack choices with reasoning, not hype
ChatGPT recommends the framework it saw most often in training data. Bob explains why Postgres over Mongo, why a queue over direct calls, why Redis vs Memcached — with reasoning you can challenge and decisions you can revisit.
Architecture that stays current
A diagram in a wiki goes stale by sprint 3. Bob reviews the actual code and refreshes the architecture against what shipped — so the doc is never a fiction, and onboarding a new engineer takes a day, not a month.
Atoms vs Eraser AI: compare features, pricing, and capabilities
| Feature | Atoms Recommended | Eraser AI |
|---|---|---|
| Output | Architecture that maps to code | Diagram in a wiki |
| Stack picks with reasoning | Written trade-offs | Generic suggestions |
| Stays in sync as code ships | Refreshed against codebase | Goes stale by sprint 3 |
| Connected to engineering | Hand-off to Alex | Hand-off via export |
| Diagram authoring | Auto-generated | Auto-generated |
How Bob works with the rest of your AI team
Bob does not work alone. Here is how the handoffs land when you build with the full team.
BobAlex
Bob designs the system; Alex builds it. No "refactor in 6 months when scale hits" tech debt baked in.
See how Alex worksBobEmma
Bob aligns the architecture to Emma's product scope. No over-engineered system for a simple feature.
See how Emma worksBobDavid
Bob designs the data model so David can query it cleanly. Analytics is a first-class citizen, not a bolt-on.
See how David worksWhat Bob designs for builders
Concrete architecture work Bob produces that maps to real code.
- Design a system
Greenfield system design
Design the system from scratch with stack choices justified against your constraints.
- Pick a stack
Stack selection
Compare stack options for your project and pick the one that fits your team and scale.
- Design a schema
Data model design
Schema, relationships, and indexes designed for the queries your product will actually run.
- Map integrations
Integration mapping
Map third-party services, webhooks, and data flow before integration work starts.
- Plan for scale
Performance and scaling plans
Identify bottlenecks and plan for the next order of magnitude before they hit production.
- Review security
Security and compliance review
Identify auth, data, and privacy concerns and address them in design instead of post-launch.
Try these prompts with Bob
Design a system from scratch
@Bob design the architecture for a multi-tenant SaaS with usage-based billing, 10k expected tenants, and Stripe Connect payouts. Pick the stack, draw the service diagram, and hand the file structure to Alex.
Pick a stack with reasoning
@Bob we are choosing between Postgres + Prisma and PlanetScale + Drizzle for the new product. Compare them against our constraints (multi-region reads, single engineer, 100ms p95) and recommend one with explicit trade-offs.
Review an existing architecture
@Bob review our current API layer. We are seeing 800ms p95 on the dashboard endpoint and want to scale to 10x traffic. Map the bottlenecks, propose changes, and write the migration plan for Alex.
Design the data model for a feature
@Bob design the schema for the referral program in Emma's PRD. Map the entities, relationships, and indexes for the queries we will actually run. Hand the schema and migration plan to Alex.
Meet the rest of Bob's AI team
No agent works alone. Tap any teammate to see how they handle their part of your product.
Frequently Asked Questions
Put Bob to work
Stop drawing diagrams nobody implements. Let Bob design systems your AI Team builds and keeps in sync inside Atoms.
