Codemix for product managers / product owners

Specs don't fail because the template was wrong.

Most spec problems are discovery problems. The intent is clear in your head, then it gets laundered through tickets, standups, design reviews and implementation until nobody is quite sure what the edge case was supposed to do.

Codemix helps you explore the product before you commit, find the gaps while they're still cheap and hand off intent that survives contact with code.

Not a better spec template. A product model humans and agents can actually build against.

codemixProject interview

Question 2 / 3setup

Question: Single choice

Which analytics delivery model should the MVP prioritise?

Pick the answer that best describes the project as it stands today.

  • Embedded analytics surfaced inside the customer's product UI
  • Standalone dashboard portal for end users
  • API-only — no default UI, consumers build their own
  • White-label dashboard builder customers can configure
  • Other

The handoff problem

Intent degrades at every step between you and what ships.

The problem is not that PMs write bad specs. It is that the product knowledge needed to write a good spec is hard to access, and intent is hard to preserve through handoff.

By the time a feature ships, the original intent has passed through tickets, standups, threads and implementation decisions. Codemix keeps it attached to the work.

Start from what exists

Understand the product before you scope the change

Most spec problems start before the spec exists. If you don't know the current product, the new work sits on guesswork.

Codemix builds a product model from the codebase: concepts, flows, screens and commands. You scope against reality, not assumptions.

Demo

Work in motion

Proposals: 2

Reviewing: 1

Approved: 1

Tasks: 5

Running: 1

Ready: 3

Blocked: 1

Completed: 3

Model inventory

Requirements

  • Intent: 8
  • Concepts: 14
  • Personas: 3
  • Flows: 9
  • Screens: 6
  • Stories: 18
  • Systems: 5

Integrations

3/4 live

  • GitHub connected
  • MCP connected
  • CLI connected
  • Slack ready

Build Checklist

TECHNICAL READINESS

  • All critical API endpoints covered by integration tests
  • Rate limiting in place on public endpoints
  • Database backups verified and restore tested

PRODUCT & ONBOARDING

  • Onboarding flow end-to-end tested with external user
  • Help docs cover the top 5 user questions
  • Feedback channel (Slack / email) ready and monitored

Project overview

See everything in flight, at a glance

The overview surfaces every active proposal, running task, and recent conversation in one place — no status updates required. Codemix keeps it current as work progresses, so anyone on the team can see what's happening and where things stand.

Clarify before you commit

Surface the gaps before engineering finds them

The questions that derail implementation usually are not hard. They are just late.

Codemix asks focused questions that map intent to real product concepts. Edge cases, conflicting rules and missing decisions get handled while they are still cheap.

React to plan changes in real time

Ready to execute from the accepted proposal.

Overview

Stratum currently has no way to respond when a customer's subscription changes. Stripe sends a notification every time a plan is upgraded, downgraded, or cancelled — but the product ignores them. This means a tenant's access level in the product can be out of step with what they're actually paying for.

Behavioral change (what must now be true)

  • When a customer upgrades, their new plan limits apply before their next action in the product.
  • When a customer downgrades, their access steps down at the end of their current billing period.
  • When a customer cancels, they keep full access until their paid period expires, then move to the free tier.
  • If the same billing notification arrives more than once, the tenant's access is updated exactly once.
  • If a notification can't be verified as genuine, it is rejected and Stripe will automatically retry.

What to implement

  1. Receive plan change notifications — The product listens for billing notifications from Stripe.
  2. Verify each notification is genuine — Before acting on any notification, the product confirms it actually came from Stripe.
  3. Apply each notification exactly once — The product records each notification it has acted on, so duplicates have no effect.
  4. Update tenant access — Once a notification is verified and accepted, the tenant's access level is updated to reflect their current plan.
  5. Confirm the behaviour end to end — Tests verify the product-level outcomes.

Out of scope

  • Sending email notifications when subscription state changes
  • Changing which features are available on each plan
  • Reacting to payment failures or invoice events
  • Registering the notification endpoint with Stripe

How it works

How Codemix carries context through the full lifecycle

Most product drift happens in the handoffs. Codemix keeps those handoffs explicit.

  1. Start with a conversation or from code.

    • Chat with Codemix if you're still at the idea stage, or import your existing codebase.

  2. Start with an interview
    Talk through the product in plain English. Codemix turns the important parts into something the team can inspect, question, and build from.

  3. Model the product
    Codemix builds a working model of the product: the concepts, screens, actions, rules, edge cases, and decisions that explain how it is meant to behave.

  4. Shape the change
    Before implementation starts, you can ask questions, edit the spec, and turn a rough idea into a concrete proposal for what should change.

  5. Write the tasks
    Once the proposal is approved, Codemix turns it into implementation work.

  6. Answer questions mid-build
    Codemix gives engineers and coding agents answers from the product model.

  7. Review what changed
    Codemix reviews the code against the product decision.

  8. Ship, then update the spec
    Codemix helps fold those decisions back into the spec.

  9. Bring the context forward
    Bring in bugs, customer feedback, support notes, and product signals.