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Decision Logs: The PM Habit That Compounds
You've made thousands of product decisions. How many can you recall?
The takeaway
Most product decisions live in Slack threads and people's heads. When those people leave or forget, the reasoning vanishes — and teams re-debate the same questions. A structured decision log is compound interest for institutional knowledge. The overhead has to be near zero, which is where AI capture changes the game.
A team spent 45 minutes debating webhooks vs polling. Chose webhooks — latency mattered for enterprise customers. Three months later, same team, same debate. New engineer, original decision-maker on leave. Nobody remembered. They chose polling.
Two contradictory implementations now live in the same codebase. This isn't unusual. It's the default.
The hidden cost of lost decisions
Teams re-litigate the same debates
"Should we support offline mode?" was decided 8 months ago. Answer: no — 99.7% of sessions are online. Nobody wrote it down. Another hour-long meeting.
New hires have no context
Your new senior engineer questions patterns in code review. They're right to ask — but without a decision log, onboarding is archaeology. Months vs hours.
Specs contradict past decisions
New spec says user content goes to S3. Six months ago, the team moved all user content to a managed CDN for performance. Nobody remembers. Engineering builds the S3 integration. Three weeks later, rework.
A decision log is not meeting notes. It's a structured record: we chose X over Y because Z, knowing the trade-off was W.
Anatomy of a decision log entry
Decision
Use server-side rendering for the dashboard, not client-side SPA.
Alternatives
Client-side SPA (React), hybrid (Next.js with selective SSR), static pre-rendering
Rationale
SSR gives faster initial load for data-heavy views. SEO doesn't matter (authenticated). Avoids client-side state complexity.
Trade-offs
Limited interactivity without hydration. Retrofitting real-time features harder. Marginally higher server costs.
Two minutes to write. Hours saved over its lifetime.
The compounding effect
Entries →
Value →
Same dynamic as compound interest: the first few deposits feel pointless, but the account balance eventually grows faster than you can contribute.
100s
of hours lost
per team per year
A duplicated debate here, a confused new hire there. Invisible in any single instance. Over a year, a team of ten loses hundreds of hours to decisions that were made but not recorded. Not a process problem — an institutional memory problem.
Decision logs vs meeting notes
Meeting Notes
Chronological — must read everything
Append-only — nobody edits them
Serves people who were in the meeting
"Discussed auth options. John prefers OAuth. Sarah raised concerns about magic links. Agreed to move forward with OAuth."
Decision Log
Captures what was decided
Structured — each entry stands alone
Living doc — superseded decisions updated
Serves people who weren't — including future-you
"Chose OAuth 2.0 with PKCE over session-based auth and magic links. Reason: enterprise SSO compatibility. Trade-off: extra sprint for mobile PKCE support."
The best decision log is one you don't have to maintain manually. AI doesn't write your decisions — it notices them and structures them.
The overhead has to approach zero. You have a conversation. You make decisions naturally. Afterward, the relevant decisions appear in your log — structured, searchable, linked to context. No extra step.
This is what we're building at DISKO.
DNA auto-captures decisions from your conversations — the alternatives, the rationale, the trade-offs — without any extra effort.
Join the beta →