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Gemini 3.5 Flash

Newer Flash, almost double the bill of the model it replaced. We'd still pick the older one.

5/5

benchmarks passed

$1.41

spent in total

tool calls

What it is.

Google's Gemini 3.5 Flash — the December 2026 update to the Flash family. Pitched as smarter than Gemini 3 Flash; in our matrix it was slower on the same tasks and ~2x the cost.

What it does well.

Five for five, like its older sibling. Schema compliance was perfect.
Marketing benchmark was actually cheaper here than on Gemini 3 Flash ($0.118 vs $0.218). The newer model is better at deciding when to stop reading Reddit.

Where to be careful.

36 tool calls on Coding. Read that again. 3.5 Flash decided the Stripe webhook task was a research project and kept poking at the docs until $0.487 ticked over.
CX was $0.623 — nearly 2x the previous-gen Flash. The model is more thorough; the rubric didn't ask for more thorough.
Total spend was $1.41 — more than GPT-5.5 and within striking distance of Gemini 3 Pro Preview. Use the cheaper Flash unless you've measured a quality gap on your workload.

Results by agent

Five real jobs.

SalesSales Research Analyst

Get financials on a company

Passed

Find Hightouch on Crunchbase and return their total funding, last round type, and a one-line description.

10 tool calls, $0.148 — 5x more tool calls than 3 Flash for an equivalent answer. The 'verify everything twice' instinct showed up here first.

MarketingMarketing Research Analyst

Find what customers are recommending on Reddit

Passed

Read a real r/sales thread on enrichment tools and rank the top 5 by how many people recommended them.

5 tool calls, $0.118. The one benchmark where 3.5 Flash genuinely improved on the previous generation.

CXCustomer Insights Analyst

Find what customers are complaining about

Passed

Pull Google Shopping reviews for AirPods Pro 2 (USB-C) and return the top 3 recurring complaints, with verbatim quotes.

5 tool calls, $0.623 — nearly 2x the 3 Flash cost for the same correct answer.

CodingSenior Engineer Assistant

Read API docs and write working code

Passed

Read Stripe's official docs and write a real, working webhook-verification function in TypeScript.

36 tool calls, $0.487. Read every docs page it could find. Final code was correct but you could have written it yourself in less time.

Web ScrapingSales Outreach Specialist

Scrape a competitor's pricing page

Passed

Scrape Apollo.io's pricing page and return every tier (Free, Basic, Professional, Organization) with name, price, and top 3 features.

Two tool calls, $0.035 — the model's most disciplined moment.

All models Run Gemini 3.5 Flash on your data