CodeValid Case Study
Which model should power your agent? Stop guessing. Test it.
Most teams default to the most powerful model — and overpay for their use case. We connected a LangChain text-to-SQL agent to CodeValid, generated tests straight from business requirements, and ran them across four models. The results changed the model decision.
The mid-tier model (Gemini Flash 3.1) passed every business requirement for this agent use case at roughly 5% of frontier cost. Same reliability, dramatically lower spend — a verified decision, not a guess.
LangChain · Text-to-SQL · 4 models · 0 lines of test code
One agent. Four models. Every requirement verified.
CodeValid generated test cases directly from the agent's business requirements — simple lookups, joins and aggregations, complex multi-table reasoning, and ambiguous edge cases — then ran the identical suite against each model.
| Model | Simple | Joins | Complex | Edge | Cost |
|---|---|---|---|---|---|
| Mistral Smallsmall | PASS | FAIL | FAIL | FAIL | 1× |
| Gemini Flash 3.1RECOMMENDEDmid-tier | PASS | PASS | PASS | PASS | 3× |
| Opus 4.6frontier | PASS | PASS | PASS | PASS | 58× |
| GPT 5.5frontier | PASS | PASS | PASS | PASS | 62× |
Backed by data
The team chose a model based on their own requirements — and can re-verify whenever a new model ships.
From repo to results — without writing a test
95%
Model spend saved by switching safely from frontier to mid-tier.
<5 min
To set up: connect a Git repo and a project management tool.
<2 min
To add a new model and re-run the full suite side by side.
0
Lines of test code written by hand.
What the model choice actually costs
Using published July 2026 list prices and a realistic text-to-SQL workload — 1M agent calls per month, ~3K input and ~300 output tokens per call — here's what each model costs in production.
Mistral Small
$0.10 / $0.30 per M · fails complex scenarios
$390 /mo
Gemini Flash 3.1
$0.25 / $1.50 per M · passes all checks
$1,200 /mo
Opus 4.6
$5.00 / $25.00 per M · passes all checks
$22,500 /mo
GPT 5.5
$5.00 / $30.00 per M · passes all checks
$24,000 /mo
Assumptions: 1M calls/month · ~3,000 input · ~300 output tokens · July 2026 list prices, before caching or batch discounts.
$255k/yr
Saved by switching from frontier to mid-tier — safely. Without a test suite, this switch is a gamble. With CodeValid, it's a verified decision.
Test it. Prove it. Ship it.
Connect your agent's repo, bring your requirements, and know — with data — which model is right for your use case.