Hand an agent a list of tasks and it will start at the top. That sounds fine until you notice the top task depends on the third one, which has not been built yet. The agent does not notice. It produces a confident, plausible attempt at work that cannot actually succeed, because the thing it needs does not exist, or it makes a change in an order that breaks everything downstream of it. This is dependency blindness, and it is one of the quieter reasons agents that write good code still fail to ship working features.
The failure is not about code quality. Each individual change might be well written. The failure is about order, and order is a dimension that a tool focused on generating one change at a time does not naturally see.
Order is a correctness property, not a nicety
Experienced engineers internalize something that is easy to forget once a machine is doing the typing: the order you do things in is part of getting them right, not just a matter of efficiency. You do not build the caller before the thing it calls. You do not migrate the consumers of a contract before the provider ships the new shape. You do not start a task whose inputs are not ready.
Get the order wrong and you do not get a slower result, you get a broken one. A change that assumes something not yet in place fails on arrival, and it fails in a way that looks like a bug in the change rather than a mistake in sequencing. This is why "the agent wrote correct code that did not work" is a coherent sentence. The code was correct. The order was not, and order is a correctness property when work has dependencies.
The two shapes of dependency blindness
Dependency blindness shows up in two related ways.
The first is starting blocked work. The agent picks up a task whose prerequisites are not done, and rather than recognizing it is blocked and saying so, it forges ahead against assumptions that are not yet true. It invents the interface it needs, or stubs the data that does not exist, and produces something that looks complete and is built on sand. The honest behavior, recognizing "I cannot proceed until X exists" and surfacing that, is exactly the behavior a blind agent skips. Separating genuinely blocked from wrong is a discipline of its own, covered in not everything that fails is a failure: blocked vs wrong.
The second is changing things in a breaking order. Even when everything can be built, the sequence matters. Removing or renaming something that other code depends on, before migrating the things that depend on it, breaks them. The safe order is the one careful humans have always used for coordinated changes: change the thing that is depended upon first, in a way that does not break the old callers, and migrate the dependents afterward. An agent blind to that order will happily delete a field in one change and break three others. When those dependents live in other repositories, the problem compounds, which is the subject of cross-boundary breakage and, at the scale of a whole product, one product, many repos.
Why single-task tools are structurally blind
Dependency blindness is not a bug in a particular agent, it is a consequence of scope. A tool that takes one task and produces one change is, by construction, looking at one node of a graph and none of the edges. It cannot see that this task waits on that one, because the relationship between tasks is not inside either task. It lives in the structure connecting them, and a tool that never looks at the structure cannot reason about it.
This is why dependency blindness gets worse exactly as the work gets more real. A single isolated task has no dependencies to be blind to. A feature that spans several changes, or a backlog of features that interlock, is mostly dependencies, and a tool that treats each item in isolation will confidently sequence them wrong.
What dependency-aware work requires
The fix, in principle, is to make the order a first-class part of planning rather than something discovered when a change breaks. That means understanding, before work starts, what a given piece of work depends on and what depends on it, and sequencing accordingly: prerequisites first, dependents after, and blocked work recognized as blocked instead of attempted.
For teams doing this by hand today, the practice is familiar. You note what each change waits on ("depends on #123"), you land providers before consumers, and you split a change that spans a boundary into ordered pieces rather than one sprawling edit. The reason careful teams bother is that the alternative is shipping a coordinated outage with a clean commit history. Reasoning about the reach of a change before making it, so you know what a given edit will touch, is the same instinct at a smaller scale, and it is covered in impact analysis before you touch a line.
The core idea is simple to state and easy to underestimate: a plan that ignores dependencies is not a faster plan, it is a plan that ships blocked and broken work confidently.
The honest limitation
Sequencing by dependency reduces broken-on-arrival work, but it does not eliminate it, and the reason is that not all coupling is visible. A dependency that is written down is easy to respect. A dependency that lives in undocumented behavior, an ordering assumption nobody recorded, or a shared resource no interface describes, is one that any planner can miss, because there is nothing to see. Respecting the dependencies you know about does nothing for the ones you do not.
The sequencing decisions themselves also stay a matter of judgment. Deciding that a particular order is safe, that a contract change can be rolled out in a given sequence, that a split is correct, are architecture calls, not mechanical ones. Tooling can help enforce an order once it is chosen. Choosing it well remains human work, and treating that judgment as automatic is its own way to ship an outage.
Where this leaves you
Dependency blindness is why agents that write correct code still ship work that does not function: they start tasks that are blocked and they change things in an order that breaks callers, because order is a correctness property that a single-task view cannot see. The way through is to treat dependency order as part of planning, prerequisites before dependents, blocked work named rather than attempted.
That is a principle we take seriously in how Loopsfinity plans work: sequencing is treated as part of getting a feature right, not an afterthought discovered when something breaks. The last-mile framing of this problem is in the last mile, the cross-repo version in cross-boundary breakage, and the full map of failure modes in why AI coding agents fail in production.