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Software architecture for coding agents
Coding agents can move fast through a codebase. Windy gives them the architecture context they need first: system diagrams, component boundaries, API contracts, data models, decisions, constraints, plans, and execution history that keep changes aligned with the design.
Architecture memory for Claude Code · Cursor · Codex · OpenCode · MCP-aware coding agents
The short version
Agents should not have to infer architecture from code alone.
A coding agent can inspect files, follow patterns, and produce a patch. But architecture is more than the code currently present. It includes ownership, boundaries, contracts, tradeoffs, lifecycle states, data flow, failure modes, and constraints. Windy keeps that architecture memory in one project-scoped source of truth that humans can review and agents can use.
Windy does not write the architecture for you. It keeps the architecture visible, durable, and available to the agents writing code.
The problem
Fast code generation can turn missing architecture into system drift.
When architecture is implicit, a coding agent has to guess. It may place logic in the wrong service, invent a new API shape, bypass an ownership boundary, duplicate state, or write tests against behavior the system should not support. The change may look reasonable locally while weakening the system globally.
Boundary drift.
Business logic moves across modules or services without a clear ownership decision.
Contract drift.
APIs, events, and schemas change without preserving compatibility.
State duplication.
The agent stores or derives state in the wrong layer.
Pattern mismatch.
A local implementation ignores the established system pattern.
Review ambiguity.
Humans cannot easily tell which architecture the agent was supposed to follow.
Coding agents need an architecture map before they modify the territory.
Architecture memory
Architecture context is more than a diagram.
Diagrams help, but coding agents need the surrounding explanation: what each component owns, how systems communicate, what contracts must stay stable, which constraints matter, and why previous decisions were made.
- System maps — the main components, services, modules, and dependencies.
- Boundaries and ownership — where behavior belongs and what each part is responsible for.
- API contracts — request/response shapes, events, schemas, and interface expectations.
- Data models — entities, relationships, lifecycle states, migrations, and persistence rules.
- Workflow diagrams — user flows, background jobs, event flows, and cross-service sequences.
- Constraints — security, privacy, tenancy, performance, reliability, cost, and deployment limits.
- Decision records — tradeoffs, rejected alternatives, and reasons behind current architecture.
- Execution history — what architecture-sensitive changes were attempted, accepted, rolled back, or left for review.
The agent needs both the shape of the system and the reasons behind that shape.
Diagrams
Architecture diagrams should guide implementation, not just meetings.
Many diagrams are created during planning and then forgotten. For coding agents, diagrams can become active project memory: a map of components, flows, states, and relationships that the agent can consult before making a change.
- System architecture diagrams — show services, modules, dependencies, and boundaries.
- Sequence diagrams — show request flows, events, callbacks, and background processes.
- State diagrams — show lifecycle rules and valid transitions.
- Entity relationship diagrams — show data models and ownership.
- Workflow diagrams — show product flows, user actions, and edge cases.
- Cloud diagrams — show infrastructure, deployment topology, and external services.
The value is not drawing a diagram. The value is giving the next coding agent a usable map.
Workflow
Capture the architecture before assigning the code change.
The safest coding-agent workflow starts with the design, turns it into a plan, then reviews implementation against the same architecture.
01
Capture the architecture.
Store diagrams, boundaries, contracts, constraints, and decisions in one project memory.
02
Co-author the requirement.
Give the coding agent your high-level intent; it expands that into detailed behavior, non-goals, edge cases, and acceptance criteria. You review and iterate with the agent until the design is right.
03
Create the plan.
Break the work into ordered tasks with dependencies and agent-ready prompts.
04
Let the agent read first.
The coding agent reads the relevant architecture memory before editing code.
05
Review against the design.
Humans compare the change against boundaries, contracts, and acceptance criteria.
06
Update the architecture memory.
If implementation changes the design, the source of truth changes too.
Architecture becomes part of the development loop, not an artifact left behind after planning.
In practice
What this looks like in practice.
A team asks a coding agent to add organization-level usage limits to a SaaS product.
Without architecture memory
The agent sees billing code, organization code, and feature gating code. It adds limit checks in several places, stores usage state in a convenient table, and updates the UI to match. The result may work, but ownership and state boundaries become unclear.
With Windy architecture memory
- The system map shows billing owns plans and invoices, while organization service owns membership and tenancy.
- The API contract defines where usage checks are requested and returned.
- The data model explains where usage counters live and how they reset.
- The decision record explains why limits are enforced at the application service boundary.
- The plan breaks work into contract update, backend enforcement, UI states, tests, and docs.
- The agent reads that architecture before editing code.
- Review checks whether the implementation preserved the intended boundaries.
The agent still writes code, but it writes inside an architecture the team can inspect.
Drift
The architecture has to stay current after the agent run.
Architecture memory is only useful if it reflects the system as it is changing. When agents implement new behavior, they may reveal missing design details or force a real architecture decision. Those changes should be written back into the project memory — a coding agent can update it directly when it detects drift, or a human can ask an agent to bring the architecture back in sync.
Review boundary changes explicitly.
If ownership moves, capture the decision.
Update contracts when behavior changes.
APIs, events, and schemas should match the implementation.
Keep diagrams current.
Important flow or component changes should update the map future agents will read.
Record execution history.
Future agents should know what changed and why.
Link plans to architecture.
Tasks should reference the diagrams, contracts, and decisions they depend on.
Architecture memory is not a static document. It is the system's evolving design record.
Windy
Windy gives coding agents shared architecture memory.
Windy gives each project one source of truth for architecture notes, diagrams, specs, contracts, decisions, plans, tasks, and execution history. Humans review and shape that memory in the web app. Coding agents read and write it over project-scoped MCP.
Windy Docs — design and architecture memory.
Architecture notes, diagrams, specs, contracts, schemas, requirements, and decisions.
Windy Plans — execution memory.
Ordered tasks, objectives, dependencies, acceptance criteria, prompts, and execution logs.
Your coding agents still implement the change. Windy makes sure they see the architecture before they do.
Best-fit use cases
When Windy helps most with software architecture.
Architecture-sensitive features
permissions, billing, authentication, integrations, state machines, and multi-service flows.
API and schema changes
work where compatibility and ownership matter.
Large refactors
migrations that need boundaries, sequencing, and review criteria.
Multi-agent development
teams using more than one coding agent against the same codebase.
Onboarding new agents or developers
projects where context should be available before anyone edits code.
Keeping diagrams useful
teams that want architecture diagrams to guide implementation, not sit in a slide deck.
FAQ
Questions, answered.
It is the explicit design context a coding agent uses before editing code: components, boundaries, contracts, data models, diagrams, constraints, decisions, and plans.
The repository shows implementation, but it may not explain ownership, tradeoffs, constraints, rejected alternatives, or the intended architecture behind the code.
Yes. Diagrams can help agents understand system shape, workflows, states, and relationships before making changes.
It gives the agent a source of truth for where code belongs, which contracts must be preserved, and what constraints matter.
No. Windy is not a coding agent. It provides the shared memory layer — Docs and Plans — that coding agents use before and after implementation.
Windy makes architecture part of the development loop. When code changes behavior or boundaries, humans or agents update the relevant docs, diagrams, decisions, plans, and execution history.
Related
Keep exploring.
Your coding agents still implement the change. Windy makes sure they see the architecture before they do.
Windy gives each project one source of truth for architecture notes, diagrams, specs, contracts, decisions, plans, tasks, and execution history.
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