Kiro supports Claude Opus 4.5. I tried it with a free Builders ID license.

On November 25, 2025, the official blog of AI coding assistant "Kiro" announced support for the latest model Claude Opus 4.5.

https://kiro.dev/blog/introducing-opus-45/

In this article, I will introduce my experience attempting to authenticate with Builders ID and verify the operation of Opus 4.5 in a Kiro-CLI environment installed on Amazon Linux 2023.

Test Environment

• OS: Amazon Linux 2023 (x86_64)
• Authentication: AWS Builders ID (Free Tier)
• Tool: Kiro-CLI (formerly q developer cli)

Installation and Setup

I installed Kiro CLI following the steps in the article below

https://dev.classmethod.jp/articles/kiro-cli-ec2-amazon-linux-2023-install/

$ curl --proto '=https' --tlsv1.2 -sSf 'https://desktop-release.q.us-east-1.amazonaws.com/latest/q-x86_64-linux.zip' -o 'kirocli.zip'
$ unzip kirocli.zip 
Archive:  kirocli.zip
   creating: q/
  inflating: q/install.sh            
  inflating: q/README                
...
  inflating: q/bin/qterm             
  inflating: q/bin/qchat             

Authentication with Builders ID

I ran the installer and performed authentication.
When asked about the login method, I selected "Use for Free with Builder ID" this time.

$ ./q/install.sh 
✔ Do you want q to modify your shell config (you will have to manually do this otherwise)? · Yes
✔ Select login method · Use for Free with Builder ID

Confirm the following code in the browser
Code: ****-****

Open this URL: https://view.awsapps.com/start/#/device?user_code=***-***
Device authorized
Logged in successfully

After browser authentication was completed, "Logged in successfully" was displayed on the terminal side, confirming that the setup was completed successfully.

Opus 4.5 Activation Verification

I checked if the latest model appears in the list right after setup.
First, I ran update to update the CLI's definition files.

$ q update

I confirmed that the Kiro-CLI version after the update was "1.20.1".

$ kiro-cli --version
kiro-cli 1.20.1

Model Switching Confirmation

I launched interactive mode with the kiro-cli command.

$ kiro-cli
⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀     ⢀⣴⣶⣶⣦⡀⠀⠀⠀⢀⣴⣶⣦⣄⡀
⠀⠀⠀⠀⠀⠀⠀     ⢰⣿⠋⠁⠈⠙⣿⡆⠀⢀⣾⡿⠁⠀⠈⢻⡆
                    (Logo AA omitted)
⠀⠀⠀⠀⠀⠀⠀     ⠀⠈⠻⠿⠿⠟⠁⠀⠀⠀⠈⠻⠿⠿⠟⠁

╭─────────────────────────────── Did you know? ────────────────────────────────╮
│                                                                              │
│                   Use /tangent or ctrl + t (customizable) to                 │
│    start isolated conversations ( ↯ ) that don't affect your main chat     │
│                                   history                                    │
│                                                                              │
╰──────────────────────────────────────────────────────────────────────────────╯

Model: Auto (/model to change) | Plan: KIRO FREE (/usage for more detail)

After launching, I entered the /model command and checked the model list and current selection status.

> /model

 Press (↑↓) to navigate · Enter(⏎) to select model 
❯ Auto | 1x credit | Models chosen by task for optimal usage and consistent quality
  claude-sonnet-4.5 | 1.3x credit | The latest Claude Sonnet model
  claude-sonnet-4 | 1.3x credit | Hybrid reasoning and coding for regular use
  claude-haiku-4.5 | 0.4x credit | The latest Claude Haiku model
  claude-opus-4.5 (current) | 2.2x credit -- experimental

As shown in the menu above, claude-opus-4.5 was selectable even with an AWS Builders ID (free tier) account and was marked as (current). Note that the credit consumption factor is set to 2.2x, and it's labeled as Experimental.

Response Content Verification

I checked the model's behavior in an actual chat.

User:

I specified Opus4.5 as the model. Is it enabled?

Kiro (AI):

I am Kiro. The documentation doesn't have clear information about which model is being used.
(omitted)
To check which model is currently enabled, try running the /model command.

The AI itself did not seem to accurately recognize its model version (or is instructed to behave as Kiro). So I provided the output from the /model command as a prompt and asked for confirmation.

User:

What model is currently enabled in Kiro-CLI?
(※pasted the previous menu screen text here)
claude-opus-4.5 (current) | 2.2x credit -- experimental

Kiro (AI):

The current Kiro-CLI has the following 5 models available:
(omitted)
5. claude-opus-4.5 (2.2x credit) - Experimental model (currently selected)

You are currently using claude-opus-4.5.

By comparing the AI's response with the CLI's status display, I determined that Opus 4.5 was properly applied.

Conclusion

I confirmed that Claude Opus 4.5 can be used with Kiro-CLI using the free AWS Builders ID on Amazon Linux 2023.
Although it is positioned as an experimental feature, being able to test the top-tier model performance from the CLI at no additional cost is a significant benefit.

However, the official announcement states "Opus 4.5 is not currently available for customers logging in with AWS IAM Identity Center." This suggests that if you are using IAM Identity Center (Pro license) for organizational use, you currently cannot select Opus 4.5.

While it's disappointing that it's not immediately available in paid Pro license environments, I look forward to official support and expanded availability in the future.