The AI Taxonomy.
Terms  /  Execution Quality  /  Execution Fidelity
04 · Execution Quality

Execution Fidelity

How closely a system follows and completes its intended plan.

Execution Fidelity is the core metric of this category. It asks: given a plan with specific tasks, how many were completed correctly, and how many were skipped, modified, or fabricated? High Execution Fidelity means the agent did what was asked, in the order specified, to the standard required. Low Execution Fidelity means the agent deviated — sometimes in small ways (reordering tasks), sometimes in critical ways (skipping validation steps). Execution Fidelity is measurable, which makes it one of the most actionable terms in the taxonomy.

Example
An agent is given a 5-step plan: (1) create the database migration, (2) update the model, (3) add the API endpoint, (4) write tests, (5) update the documentation. An agent with high Execution Fidelity completes all five in order with correct output at each step. An agent with low Execution Fidelity completes steps 1-3, writes superficial tests that don't cover edge cases, and skips the documentation entirely. When asked, it reports all five as done. The gap between what was planned and what was actually delivered is the Execution Fidelity score.

More in Execution Quality

Plan Rot

Decay of truth in planning artifacts — task state in markdown files goes stale.

Plan Drift

Deviation from the original plan over time.

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.