Gemini 3.1 Pro Preview Custom Tools
Gemini 3.1 Pro Preview Custom Tools is a variant of Gemini 3.1 Pro that improves tool selection behavior by preventing overuse of a general bash tool when more efficient third-party...
GoogleVerified 24/09/2026Released 25/02/202601 / decision
Decision snapshot
Each figure sits next to the middle of the field, so it can be read as dear or cheap, wide or narrow, rather than floating on its own. Compared against the 231 models we track, not against an absolute standard.
Capability
Not measured
No published benchmark scores yet
Input / 1M tokens
$2.00
field median $0.43
Output / 1M tokens
$12.00
field median $1.80
Context
1,049K
field median 500K
02 / overview
What Gemini 3.1 Pro Preview Custom Tools is, and when to reach for it
Four questions, answered separately, because somebody arrives at one of them rather than at the top of the page.
This model has no written explanation yet.
The page is created the moment a model appears in a provider's catalogue, and the writing follows. Until then the measured sections below are the whole page.
How we decide what counts as evidenceFollows Gemini 3.1 Pro Preview. Superseded by Gemini 3.1 Flash Lite. See the whole line.
03 / evidence
How much of this is verified
Split by category, so a strong number never hides a thin evidence base. Verified means we read it on the benchmark's own published results; a provider's claim about its own model is shown and labelled rather than dropped.
No published benchmark scores for this model yet.
We publish a score only where we can link the result to where it was published. Until a benchmark result for this model exists in a source we read, this section stays empty rather than being filled with a provider's marketing figure.
How we decide what counts as evidence04 / ledger
Benchmark ledger
Every published row, grouped by category, each compared with the best published score on the same benchmark. 'Is 64% good' is a question nobody can answer; '26 points behind the leader' is one anybody can.
Nothing in the ledger yet.
Each row here carries a score, the benchmark it came from, what the leading model scored on the same test, and a link to the published result. Rows appear as results are published and read.
How we decide what counts as evidence05 / capability
Capability shape
Where this model is strong, and against how many peers. Ranks are against models with evidence in that category, not against everything we track: ranking against models nobody tested would rank who published, not who is better.
No category scores to shape yet.
A category score is the weighted mean of the benchmarks published for it. With no published rows there is nothing to average, and an empty chart drawn at zero would say something false.
How we decide what counts as evidence06 / cost
What it costs
List API rates as last read from the provider, with the source on every row, plus every change we have recorded since we started tracking it.
| Charge | Price | Unit | Read on | Source |
|---|---|---|---|---|
| Input | $2.00 | per 1M tokens | 2026-09-24 | Check |
| Output | $12.00 | per 1M tokens | 2026-09-24 | Check |
| Workload | Input / month | Output / month | Cost |
|---|---|---|---|
| A small product team | 20M tokens | 5M tokens | $100.00 |
| A busy support assistant | 200M tokens | 40M tokens | $880.00 |
| A document pipeline | 1000M tokens | 100M tokens | $3,200.00 |
List API rates, no caching and no batch discount, which both providers offer and which change the answer a great deal. Treat these as the ceiling, not the bill.
07 / specs
Specifications
As listed by the provider's own catalogue and re-read every few hours. Anything absent is absent there too.
| Context window | 1,048,576 tokens |
|---|---|
| Maximum output | 65,536 tokens |
| Modalities | text, audio, image, video, file |
| Released | 25/02/2026 |
| Status | Current |
| Catalogue identifier | google/gemini-3.1-pro-preview-customtools |
08 / lineage
Lineage
What this model replaced, what replaced it, and what else its provider has in the field.
Also from Google
- Gemini 3.8 Flash02/09/2026
- Gemini 3.7 Flash13/08/2026
- Gemini 3.6 Flash21/07/2026
- Gemini 3.5 Flash Lite21/07/2026
- Nano Banana 2 Lite (Gemini 3.1 Flash Lite Image)30/06/2026
- Nano Banana Pro (Gemini 3 Pro Image)18/06/2026
- Nano Banana 2 (Gemini 3.1 Flash Image)18/06/2026
- Gemini 3.5 Flash19/05/2026
- Gemini 3.1 Flash Lite07/05/2026
- Gemini Flash Latest27/04/2026
- Gemini Pro Latest27/04/2026
- Gemma 4 26B A4B03/04/2026
09 / line
The line
Every model in this family in release order, so a page from eight months ago says in one glance that two newer ones exist.
Came before
← Gemini 3.1 Pro PreviewCame after
Gemini 3.1 Flash Lite →- 01Gemini 2.5 Flash17/06/2025
- 02Gemini 2.5 Flash Lite22/07/2025
- 03Gemini 3.1 Pro Preview19/02/2026
- 04Gemini 3.1 Pro Preview Custom Tools25/02/2026
- 05Gemini 3.1 Flash Lite07/05/2026
- 06Gemini 3.5 Flash19/05/2026
- 07Gemini 3.5 Flash Lite21/07/2026
- 08Gemini 3.6 Flash21/07/2026
- 09Gemini 3.7 Flash13/08/2026
- 10Gemini 3.8 Flash02/09/2026
Ordered by release date and worked out from the naming, so a new member slots in as soon as its page exists. A retired model keeps its page and its place in the line.
10 / notes
Our notes
What this model changes for a brand trying to be cited in AI answers, and every change we have logged since it launched.
Change log
Nothing published here yet. Changes appear within hours of a provider announcing them.
11 / questions
Questions
The things people ask about this model, answered from what is on this page rather than from anywhere else.
- What does Gemini 3.1 Pro Preview Custom Tools cost?
- $2.00 per million input tokens and $12.00 per million output tokens, as last read from the provider. The cost section works that into a monthly figure.
- How current is this page?
- The catalogue behind it is re-read every three hours, and the stamp at the top says when it last confirmed. A re-check that finds nothing changed updates that stamp and deliberately does not touch the page’s modified date.
- Why are some sections empty?
- Because nothing has been published that we can link to. We would rather show an empty section than a number you cannot check. Our methodology sets out what counts.
Is Gemini 3.1 Pro Preview Custom Tools recommending you?
Models change what gets cited. We measure whether AI answers name your brand or your competitors across every assistant, and show you what to change.