Summary
Using the new app builder with the default Opus 4.8 model, even basic tasks (e.g. 'expand this section') can burn ~100 AI credits, quickly exhausting the monthly allotment, and there's a question of whether this is expected or reducible.
AI Response
This is expected behavior rather than a bug: before any prompt runs, the builder pre-loads a large baseline context (resource schemas, source files, function outputs, dependency metadata, and conversation history), and credit consumption scales with reasoning complexity, output size, and total context processed. Several documented practices can meaningfully reduce burn: switch to a lighter model for simple edits (reserve Opus 4.8 for complex, multi-step changes), write precise prompts that name resources/components directly to avoid costly re-tries, and start a fresh thread when the task shifts so context doesn't accumulate. Credit and per-response usage can be tracked under Settings > Plans & Billing (Usage tab) and by hovering the icon below each agent response in the Chat tab.
Sources
Token management for app building | Retool Docs
Explains why baseline context is large and lists concrete ways to cut credit usage—model selection by task complexity, precise prompting, new threads, and usage monitoring.
Staff announcement confirming lighter-weight models (Claude Sonnet 5, the GPT-5.6 family, and Claude Fable 5) are now selectable, supporting the switch away from the default Opus 4.8 for simpler tasks.
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