Resolved OpenAI regional hostname errorPublic

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Model

Claude Opus 4.5 (latest)

Started

Jan 29, 12:35 AM

Messages74

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Summary

Closed, Completed

Understand
Analyzed GitHub issue and related code.
Understand
Edit
Updated documentation with correct URL format.
Edit
Verify
Commented on issue explaining user error and fix.
Verify

Analyze GitHub issue(s): https://github.com/badlogic/pi-mono/issues/956

For each issue:

Read the issue in full, including all comments and linked issues/PRs.
For bugs:
- Ignore any root cause analysis in the issue (likely wrong)
- Read all related code files in full (no truncation)
- Trace the code path and identify the actual root cause
- Propose a fix
For feature requests:
- Read all related code files in full (no truncation)
- Propose the most concise implementation approach
- List affected files and changes needed

Do NOT implement unless explicitly asked. Analyze and propose only.

Let me read the relevant OpenAI provider code and understand how base URLs are handled:

Let me check the OpenAI models configuration to see what the default baseUrl looks like:

Now I understand the issue. Let me verify the OpenAI SDK behavior and check if there's any documentation for the models.json format:

Let me check how the OpenAI response streaming handles error cases:

Let me check the OpenAI completions provider as well to see how it handles baseURL:

Issue Analysis: #956 - OpenAI Regional Hostname Error

Summary

Users with OpenAI projects configured for US data residency get a 401 error:

"Attempted to access resource with incorrect regional hostname. Please make your request to us.api.openai.com"

The user attempted to fix this by setting baseUrl in models.json, but used the wrong URL format.

Root Cause

User error with missing path suffix. The user configured:

But the correct configuration requires the /v1 path:

OpenAI models have baseUrl: "https://api.openai.com/v1" by default. When the user overrides without /v1, the OpenAI SDK hits https://us.api.openai.com/chat/completions which returns an HTML error page. The streaming code then displays HTML fragments as text (the itle></head> and /center> garbage the user saw).

Proposed Fix

Two-part solution:

1. Documentation update (essential): Add explicit example for OpenAI regional endpoints in docs/models.md

2. Environment variable support (nice-to-have): Support OPENAI_BASE_URL like the official OpenAI SDK does, allowing users to set OPENAI_BASE_URL=https://us.api.openai.com/v1 as an alternative to models.json

Files to Modify

File	Change
`packages/coding-agent/docs/models.md`	Add "OpenAI Regional Endpoints" section with correct example
`packages/ai/src/providers/openai-responses.ts`	Check `OPENAI_BASE_URL` env var in `createClient()`
`packages/ai/src/providers/openai-completions.ts`	Check `OPENAI_BASE_URL` env var in `createClient()`
`packages/coding-agent/src/cli/args.ts`	Document `OPENAI_BASE_URL` in env vars section
`packages/ai/README.md`	Document `OPENAI_BASE_URL` environment variable

Implementation Details

For openai-responses.ts and openai-completions.ts, modify createClient():

Actually, the logic should be: env var overrides model.baseUrl when provider is "openai":

For docs/models.md, add under "Overriding Built-in Providers":

markdown

### OpenAI Regional Endpoints
For OpenAI projects with data residency requirements (US, EU), override the base URL.Note: The `/v1` path suffix is required.
```json{  "providers": {    "openai": {      "baseUrl": "https://us.api.openai.com/v1"    }  }}

Or set the environment variable: OPENAI_BASE_URL=https://us.api.openai.com/v1

just update docs, then comment on the issue telling the user what they did wrong and how to fix it

Now let me comment on the issue:

Done. I've:

Updated docs/models.md: Added "OpenAI Regional Endpoints" subsection under "Overriding Built-in Providers" with the correct URL format (https://us.api.openai.com/v1)
Commented on issue #956: Explained that the missing /v1 suffix caused the SDK to hit an HTML page instead of the API, with the correct configuration example