Implement Anthropic API key flow for Assistant

[nightnei]

Related issues

• Fixes STU-1777

How AI was used in this PR

AI was almost useless and just misleading.
I investigated it myself and came up with the approach. AI just followed my instructions and double-checked them.

Proposed Changes

The issue: In Assistant tab of Studio, when we select API key - nothing happens.

The reason: we are using password function from '@inquirer/prompts', to request the Anthropic API key in terminal. It doesn't work for UI, since it's intended to be used only for command line.

What I did: Inverted the password collection dependency by injecting a collectPassword callback through the adapter interface, so each environment (terminal, Desktop UI) owns its own collection strategy instead of the provider hardcoding an interactive TTY prompt.

Testing Instructions

1. npm run cli:build
2. node apps/cli/dist/cli/main.mjs code
3. Select api key and provide yours
4. Assert that no regresion, it work well as before
5. npm start
6. Open Assistant tab
7. Open ~/.studio/cli.json
8. Remove aiProvider and anthropicApiKey, since they we added while testing terminal above
9. Say hi to Assistant
10. Select API key
11. Assert that you see the input to provide your password
12. Fill in your password
13. Assert that now the API key flow works

Known issues - this PR doesn't cover the case when incorrect API key was provided. First of all this PR is already pretty big, I want to keep it focused on the specific initial issue. And handling incorrect APi key deserves own PR, as I have no idea why errors are printed in Assistant and disappear almost immediatelly from UI. I will create separate Linear issue for it.
Also, I will think more about it, but maybe the best way is introducing /api-key, so that we have aligned way with studio code in the terminal.

[wpmobilebot]

📊 Performance Test Results

Comparing 19cd6da vs trunk

app-size

Metric	trunk	19cd6da	Diff	Change
App Size (Mac)	1332.82 MB	1332.79 MB	0.02 MB	⚪ 0.0%

site-editor

Metric	trunk	19cd6da	Diff	Change
load	1630 ms	1646 ms	+16 ms	⚪ 0.0%

site-startup

Metric	trunk	19cd6da	Diff	Change
siteCreation	9032 ms	9001 ms	31 ms	⚪ 0.0%
siteStartup	4427 ms	4414 ms	13 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[youknowriad]

Can we instead disable the "api key" provider entirely from Studio App and rely full on the .com provider? Alternative would be to surface the API KEY config in the app settings but I'm not sure it's necessary for a start. I think there's not much value for the moment to provide your own API KEY specially if we're still giving free access.

[nightnei]

Can we instead disable the "api key" provider entirely from Studio App and rely full on the .com provider? Alternative would be to surface the API KEY config in the app settings but I'm not sure it's necessary for a start. I think there's not much value for the moment to provide your own API KEY specially if we're still giving free access.

@youknowriad do you mean to:

1. Remove this:
   

2. If the user opens the Assistant tab and if aiProvider is not set yet, then set it to wpcom automatically in cli.json

Do I understand your suggestion correctly?

I think it doesn't make sense to show only 1 open to chose, like this:

[sejas]

Vova, thanks for working to add Anthropic API. I tested it and confirmed I was able to add my Anthropic API key and worked as expected.

In the testing instructions there is a small typo with the Studio home folder. The folder is hidden and requires a dot Open ~/.studio/cli.json.

Before	After
api-key-before.mp4	enter-anthropic-api-key.mp4

I agree with Riad and we can default to WPcom provider without asking the user, at least initially.

[youknowriad]

Yes, that was my suggestion, I'm hesitant about proposing the removal of the anthropic provider entirely from the the code command as well. (CLI). I think it's still useful for me to check whether an issue is due to our proxy or not, but other than that, I don't see it being useful to users right now.