Configure an OpenAI-Compatible Provider in Cline for Document Q&A With Source Attribution

Configure Cline for document Q&A—not just model access

If your goal is to let a coding agent answer questions about project documents and show where each answer came from, there are two separate jobs: connect Cline to a model endpoint, then build a retrieval-and-attribution workflow around that connection. Cline's SDK documentation covers provider credentials, model IDs, and the LLM gateway. It does not document a built-in document search or citation feature. Read the Cline model-provider documentation.

The setup below targets developers using Cline's SDK. It is not a step-by-step configuration for the Cline desktop extension or another interface; the supplied source does not establish those settings. For the SDK, Cline documents an openai-compatible provider with an API key, base URL, and model ID. OneMux can be a practical route for accessing models through an OpenAI-compatible API, but compatibility with a specific Cline workflow depends on the endpoint and request features you use.

Prerequisites

Before configuring the agent, gather:

• A Cline SDK project using the relevant @cline/agents and provider packages. Cline says @cline/agents and @cline/core use its LLM layer internally; consult the package documentation for the exact imports and constructor shape for your version.
• An API key for the provider you intend to use, stored outside source control.
• The provider's OpenAI-compatible base URL and the exact model ID it accepts.
• Documents available to your application, plus a retrieval method that can find relevant passages and preserve their source metadata.

For OneMux account and API setup, start with the OneMux quickstart and API documentation. Check the current endpoint and model identifier in the documentation before using them: this article does not assert a particular model, endpoint, or Cline integration has been tested.

Configure the OpenAI-compatible provider

Cline's documented provider configuration pattern is:

const agent = new Agent({
  providerId: "openai-compatible",
  modelId: process.env.MODEL_ID,
  apiKey: process.env.PROVIDER_API_KEY,
  baseUrl: process.env.PROVIDER_BASE_URL,
})

The Agent symbol and package imports are omitted because the supplied provider reference does not specify them. Use the import and any additional required options from the documentation for the version installed in your project. Set MODEL_ID, PROVIDER_API_KEY, and PROVIDER_BASE_URL in your local environment or secret manager; these are example application environment variable names, not Cline-required variable names. Cline's documented common variables for OpenAI and other named providers do not establish a standard variable name for every OpenAI-compatible service.

For a OneMux-backed configuration, obtain the current base URL, key, and model ID from OneMux's API docs, then provide those values in the corresponding fields. Do not assume that every OpenAI-compatible endpoint accepts every optional parameter or feature. Confirm the endpoint's documented request format, authentication method, and model availability. In particular, compatibility is conditional on the provider supporting the parameters your agent sends.

Add source attribution to document answers

Connecting a model does not make it search your files or cite them. Build that behavior in the application layer:

1. Index documents with stable identifiers. Store a source ID, document title, and page, section, or other location for each retrievable passage. Keep that metadata alongside the text.
2. Retrieve before asking. Search for passages relevant to the user's question, then include a small set of results as context. The search implementation and document store are outside the provider configuration described by Cline's source.
3. Require references in the response. Ask the model to answer only from supplied passages and return references using the IDs and locations you provided. For example, request a concise answer plus a list of citation IDs.
4. Validate citations in code. Check that every returned ID exists in the retrieved set, and render links or labels from your own metadata. If no passage supports an answer, have the workflow say that the documents do not establish it rather than presenting an uncited claim.

A prompt for the retrieval step could be:

Answer the question using only the supplied document passages.
For each factual claim, cite the passage ID and location in brackets.
If the passages do not support an answer, say so.

Question: {{question}}
Passages:
{{retrieved_passages_with_ids_and_locations}}

This is an application-level pattern, not a documented Cline citation API. A model can produce a reference that looks plausible but is incorrect, so validate the reference against retrieved metadata and, where necessary, the cited text. For high-stakes answers, have a person review the answer and its supporting passage.

What to verify and how to troubleshoot

Authentication fails: Check that the key is present in the process environment, that it belongs to the configured service, and that the endpoint expects the authentication method used by your client. Avoid printing secrets in logs.

The model is not found: Confirm the exact model ID with the provider. The Cline reference uses a provider-specific model ID; it does not promise that a given ID is available through every compatible service.

Requests fail despite an OpenAI-compatible label: Verify the base URL, including whether the provider expects a version path such as /v1. Then compare the request parameters and response format used by your installed Cline version with the endpoint's documented support. The supplied Cline source does not list a universal set of supported parameters for third-party endpoints.

Answers lack reliable sources: Check that retrieval returned relevant passages, that each passage has a stable identifier and location, and that your application validates returned references. Provider setup alone cannot fix missing or incorrect retrieval metadata.

Cline's model-provider layer also exposes a gateway and model metadata, including fields such as context window, maximum tokens, pricing, and capabilities. The source notes that token usage and cost can appear in agent results and usage events, but does not establish that every compatible provider exposes every metadata field. See the Cline provider reference for the documented gateway details.

Is this the right setup?

Use this approach when your coding agent needs to query project documentation and you can implement retrieval and citation checks in your own application. It separates model access from the parts that make answers auditable. It is not a turnkey document-Q&A feature, and the cited Cline page does not verify a OneMux-specific integration or document-citation behavior.

For a practical next step, configure the endpoint with the provider's documented values, test a simple request, then add retrieval and citation validation as separate stages. You can review available options on the OneMux models page and consult OneMux pricing for current account costs; this tutorial makes no price or performance comparison.

FAQ

Does Cline's OpenAI-compatible provider automatically cite documents?

No such feature is established by the supplied Cline provider documentation. It describes provider setup and gateway capabilities. Your application must retrieve documents, provide source metadata, request references, and validate them.

Can I use OneMux with Cline?

The Cline SDK documentation describes an openai-compatible provider. OneMux provides access to models through one OpenAI-compatible API. Whether a particular setup works depends on the current endpoint, model ID, authentication, and request parameters; this article does not claim a tested integration.

Is this configuration for the Cline editor extension?

The cited source is about Cline SDK model providers. It does not establish how to configure a provider in the Cline editor extension or other interfaces. Follow the documentation for the specific Cline product and version you use.

How should an agent respond when no source supports an answer?

Instruct it to say that the supplied documents do not establish the answer, and validate citations against the passages retrieved by your application. Do not treat a model-generated citation as proof that the referenced material supports the claim.

Sources

• Cline SDK: Model Providers — provider configuration, OpenAI-compatible setup, gateway, model metadata, and usage information.