Your agent forgot the architecture decision
You chose Postgres over SQLite in March, argued about it for an hour, and agreed. In July the agent proposes SQLite, confidently, with reasoning that reopens the whole debate.
Sources checked 2026-09-25.
Why decisions evaporate
Architecture decisions live in two places: code and conversation. Code records the outcome. Conversation records the reasoning, the alternatives, and the constraints, and conversation is the part that ends.
Repositories have a partial answer: ADRs, design docs, and long commit messages. They work when someone writes them at the moment of the decision and keeps them findable, which is exactly when everyone is busy shipping.
Agent frameworks add more surface area. LangGraph threads, CrewAI crews, and AutoGen agents each carry context inside a boundary, and the decision made in one boundary does not cross to the next.
Free fixes you can do today
These work today, with no new tools.
- 1
Write one-line ADRs at decision time
Decision, date, one sentence of why. A folder of these is more useful than one design doc nobody updates.
- 2
Put the top five constraints where the agent reads first
Five lines at the top of the instruction file covers most of the damage. The rest lives in search.
- 3
Reference the ADR in the commit that implements it
The link from code to reasoning is what makes the reasoning discoverable later.
- 4
Re-state decisions in the session where they matter
When work touches a settled area, say the decision and the reason out loud. One sentence prevents the re-litigation.
The durable fix
Decisions with dates and reasons are exactly what a memory store is good at. Store them as they happen, from whichever tool you are in, and retrieval brings them back when the topic returns.
Time-window search is the part files cannot do: ask what was decided in March about persistence and get the entries from that window, not a full-text guess.
- 1
Store the decision in the session where it is made
With hooks installed, this is automatic for completed turns. You can also store explicitly over MCP or through the dashboard.
- 2
Adopt a rule for what qualifies
Anything that costs more than an hour to reconsider gets stored: data stores, auth, deploy topology, public interfaces, naming that anything depends on.
- 3
Search by time when memory gets huge
The time-window query answers "what changed last month" directly, which is the question that keeps coming back after a long project.
Full setup guide: Claude Code setup guide
Store the first decision today. 14 days free, then $20 per month with 200M tokens.
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Sources checked 2026-09-25. Tool behavior changes; check the vendor docs before relying on a detail.