Fix: inference-parser misses /chat/completions from /v1-less proxies (opencode, litellm)

[msteinder]

Why

OpenAI-compatible proxies such as litellm (used by opencode) post to /chat/completions without the /v1 prefix. The OnRequest dispatch switch in inference-parser only matched /v1/chat/completions and /v1/completions, so these requests fell through to the default: return Continue arm — pctx.Extensions.Inference was never populated and abctl showed — for model, method, and token counts on every opencode request.

Observed before the fix:

9    14:13:56.91   out   │┌ req   —    —                    ete-litellm.ai-mode…
9    14:13:59.27   out   │└ resp  —    —    200  2.36s       ete-litellm.ai-mode…

What changed

authbridge/authlib/plugins/inferenceparser/plugin.go

• Extended the OnRequest switch case to also match /chat/completions and /completions.

authbridge/authlib/plugins/inferenceparser/plugin_test.go

• Added TestInferenceParser_VlessPath_ChatCompletions and TestInferenceParser_VlessPath_Completions.

No changes to OnResponse or OnResponseFrame — the default branch there already routes to the OpenAI parsers, which is correct.

Testing

$ cd authbridge/authlib && go test ./plugins/inferenceparser/...
ok  github.com/rossoctl/cortex/authbridge/authlib/plugins/inferenceparser

Verified end-to-end: opencode requests through authbridge-proxy --demo now show model, token counts, and method in abctl.

Related issue(s)

Fixes #822

Assisted-By: Claude (Anthropic AI) noreply@anthropic.com

Summary by CodeRabbit

• Bug Fixes
  • Added support for OpenAI-compatible /chat/completions and /completions endpoints without the /v1 prefix.
  • Requests through compatible proxies are now correctly parsed, including model details and action tracking.

[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

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Run ID: 430ff944-b13b-46c3-b1e0-c94f6351ec9a

📥 Commits

Reviewing files that changed from the base of the PR and between cb8bceb and 4bcb677.

📒 Files selected for processing (2)

• authbridge/authlib/plugins/inferenceparser/plugin.go
• authbridge/authlib/plugins/inferenceparser/plugin_test.go

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📝 Walkthrough

Walkthrough

The inference parser now handles OpenAI-compatible /chat/completions and /completions paths without the /v1 prefix. Tests verify inference metadata, model extraction, and parser continuation.

Changes

OpenAI endpoint support

Layer / File(s)	Summary
Unversioned endpoint dispatch and validation authbridge/authlib/plugins/inferenceparser/plugin.go, authbridge/authlib/plugins/inferenceparser/plugin_test.go	The request parser accepts unversioned chat and completion paths. Tests verify parsed models, inference extensions, action state, and Continue results.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 4bcb6

The change enables metadata extraction for two additional compatible completion paths using the existing parsing behavior, with no change to authorization, routing, or request handling. No actionable merge-blocking risk remains.

Suggested reviewers: huang195, ibrahim2595

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the inference-parser fix for /v1-less OpenAI-compatible proxy paths. It is concise and directly related to the primary change.
Linked Issues check	✅ Passed	The changes satisfy issue #822 by adding /chat/completions and /completions to OnRequest path matching. The added tests verify inference parsing for both paths, including model capture and action stat…
Out of Scope Changes check	✅ Passed	All code and test changes directly support issue #822. No unrelated or out-of-scope changes are present.

Full details: Linked Issues check

Explanation

The changes satisfy issue #822 by adding /chat/completions and /completions to OnRequest path matching. The added tests verify inference parsing for both paths, including model capture and action status.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/inference-parser-vless-paths

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