Reading the stack means understanding what's been built, what's been bought, and what's been bolted together over time. The core systems, the integrations between them, the data flowing through them, and the AI layers being added on top. What the architecture diagram says is true, and what the actual dependencies look like under load.
Most organisations have plenty of systems, and the question is whether they cohere. Whether data flows where it needs to, whether the systems supporting one part of the business can talk to those supporting another, whether the AI tools being adopted have access to the right context to be useful.
The average scaling company carries between 20 and 40 percent of its technology estate as accumulated debt: older systems, deferred upgrades, integration shortcuts that worked at the time. Engineering teams spend roughly two-fifths of their week on this debt rather than on new value. AI initiatives stall most often because the data feeding the model lives in too many places and has too many definitions.