Evidence · independent research · 2025–2026
How AI coding agents fail
In a taxonomy of 20,574 real AI coding-agent sessions across 1,639 repositories — human-validated at 0.93 precision — 38% of agent failures were an instruction the developer had already given, and simply not followed. Of those failures, 91% were resolved only because a human pushed back; the agents self-corrected in just 2.99% of cases.
Separately, trajectory analysis found 76% of an agent’s tokens are spent reading code rather than writing or running it.
All of this is independent, published research. None of it tested Codee3 — it measures how agents behave, not whether any particular structure fixes it.
- 38%
How often do agents ignore instructions you already gave?
38% of agent failures were an instruction the developer had already given, not followed.
- Method
- Taxonomy of 20,574 real coding-agent sessions across 1,639 repositories, human-validated at 0.93 precision.
- Source
- How Coding Agents Fail Their Users, 2026
- Limit
- Measures what agents did in real sessions. It did not test Codee3, and it does not establish that any particular structure fixes it.
- 91%
Do agents fix their own mistakes?
91% of those failures were only resolved because a human pushed back.
- Method
- Same dataset. Agents self-corrected in 2.99% of cases.
- Source
- How Coding Agents Fail Their Users, 2026
- Limit
- A measure of who does the correcting, not of how costly the correcting is.
- 76%
Where does an agent actually spend its effort?
76% of an agent’s tokens are spent reading, not writing or running code.
- Method
- Trajectory analysis of a coding agent on SWE-Bench Verified; cross-validated at 67.5% on a second model.
- Source
- SWE-Pruner, 2026
- Limit
- Measures exploration inside a single session. It does not measure the cost of starting a new one, which nobody has yet measured.
A pattern of ignored instructions is not a memory problem. It is an authority problem.
When a repository cannot say which of its own documents govern, an agent has nothing to be held to. The reasoning behind that reading — and an open specification for fixing it by hand — is set out separately.