Missleading documentation or incorrect behaviour about small_model

[podliy16]

Description

Looking at the documentation for OpenCode at https://opencode.ai/docs/config/:

The small_model option configures a separate model for lightweight tasks like title generation. By default, OpenCode tries to use a cheaper model if one is available from your provider, otherwise it falls back to your main model.

However

opencode/packages/opencode/src/provider/provider.ts

Line 1109 in 253b7ea

export async function getSmallModel(providerID: string) {

The code shows that OpenCode first attempts to use its own opencode provider for the small model. Only if the opencode provider is unavailable does it fall back to the user's main configured model.

This discrepancy can lead to unexpected behavior. For example, when using deepseek-reasoner via the DeepSeek provider as a main model, OpenCode silently used opencode nano-5-gpt as the small model. This means session data was sent to OpenCode's servers without explicit notice, raising potential privacy concerns.

Plugins

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OpenCode version

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Steps to reproduce

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Screenshot and/or share link

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Operating System

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Terminal

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[github-actions]

This issue might be a duplicate of existing issues. Please check:

• [BUG] Default small_model charges users when free alternative exists on Copilot #6802: [BUG] Default small_model charges users when free alternative exists on Copilot - addresses the same problem of small_model silently using OpenCode's provider without explicit user knowledge
• Github Copilot burns premium quota for non-premium models #6816: Github Copilot burns premium quota for non-premium models - related issue about unexpected model selection causing unwanted charges

Feel free to ignore if your specific case differs from these existing reports.

[Nindaleth]

This means session data was sent to OpenCode's servers without explicit notice, raising potential privacy concerns.

If you don't want opencode provider to be active, you can disable it in your config:

{
  "$schema": "https://opencode.ai/config.json",
  "disabled_providers": ["opencode"]
}

Or it's also possible to configure a whitelist-only using enabled_providers.

What I agree is done incorrectly in the linked functions is this:

    if (providerID.startsWith("github-copilot")) {
        // prioritize free models for github copilot
        priority = ["gpt-5-mini", "claude-haiku-4.5", ...priority]
    }

claude-haiku-4.5 has a cost of 0.33 premium requests per request, it's absolutely not free; if more models are needed than just gpt-5-mini, then gpt-4.1 is another candidate

[podliy16]

Yes, my point is not about how to configure it, but that the stated default behavior in the documentation contradicts the actual code.

More importantly, the actual default behavior—silently sending data to a third-party service (opencode) when the user has configured a different primary provider—constitutes a privacy issue and should be clearly communicated.

[Nindaleth]

I don't see any silent sending of data to 3rd-party services. I only see that if you already use opencode provider, you get the most appropriate small model for it. If I use github-copilot, I'll get the most appropriate model for github-copilot, the check for opencode is just earlier but not relevant (EDIT: nor applied) to my use in that case.

[podliy16]

I don't see any silent sending of data to 3rd-party services.

I launched opencode CLI, chose DeepSeek as the provider, and started using it without any additional configuration. I expected that my session and my data would be sent only to DeepSeek. However, for some reason, my session data is being sent to opencode as well.

That's what I mean by "silent sending data to 3rd-party services"