Plan Drift is gradual and often well-intentioned. The agent encounters an unexpected issue and adjusts its approach. It finds a "better" way to implement something and silently changes course. It gets sidetracked by a related problem and follows that thread instead. Each individual deviation might make sense in isolation, but cumulatively they mean the agent is no longer working on the plan it was given. Plan Drift is particularly dangerous because the agent often believes it's still following the plan — it's just "adapting." Without inspection, the user won't realize the drift until the final output doesn't match expectations.
More in Execution Quality
Execution Fidelity
How closely a system follows and completes its intended plan.
Plan Rot
Decay of truth in planning artifacts — task state in markdown files goes stale.
Execution Hallucination
Claiming work is done when it is not.
Execution Integrity
Consistent, verifiable completion of planned tasks with evidence.
Plan Resilience
A plan's ability to remain accurate and actionable over time despite changing conditions. The opposite of Plan Rot.
Task Accountability
Every task has a verifiable record of who did what, when, and whether it actually completed.
Agentic Scope Creep
An agent silently expanding beyond what was delegated, usually from lack of a clear plan or direction. Adds breadth the user didn't ask for.
Depth Fixation
The agent keeps drilling deeper into implementation detail, generating new sub-tasks and refinements rather than recognizing the work is done and returning control to the user. Expands depth rather than breadth.