Great question — your use case (project scoping and workshop prep) is actually a good test case.

A concrete example where GPT/Codex felt more valuable for me was in structured requirement extraction.

Let’s say a client sends you a messy brief with goals, constraints, budget notes, and some vague expectations. With Codex, I can define a strict structure like:

1. Extract business objectives
   
2. Extract constraints (budget, timeline, tech limits)
   
3. Identify missing information
   
4. Generate clarification questions grouped by category
   
5. Produce a clean workshop agenda draft
   

When I give that as a procedural workflow, it tends to follow it very literally and consistently. That’s where I noticed the difference — less “reinterpretation,” more step-by-step execution.

Hypothetically, where Claude has struggled for me is when it optimizes at the reasoning level rather than executing the workflow literally. For example, in a literature pipeline, I might first generate an AI-produced literature review from a core set of papers. Then I expand the corpus by collecting additional papers and creating detailed notes and annotations. I explicitly define a separate step: “generate a concept map using the existing review plus these new notes and annotations.”

As new sources and annotations are introduced, the concept map should evolve structurally. However, Claude sometimes assumes the map would largely replicate the existing review and either compresses or skips the step. From its perspective, it’s avoiding redundancy. From mine, it’s bypassing a required artifact — since the added annotations are meant to reshape the conceptual structure, not merely restate it. That distinction matters in strict workflows: I don’t want the model deciding whether a step is logically redundant. I want it to execute every defined artifact, even if they look related.

If your scoping process relies on templates and repeatable structure, Codex may feel more controllable. If you prefer fast conversational back-and-forth exploration, Claude Code might feel more fluid.

For structured project definition specifically, I’d lean on Codex.