[Bug]: agents.sisyphus-junior.model configuration is ignored - model resolution priority issue

[DevSissi]

Prerequisites

• I will write this issue in English (see our Language Policy)
• I have searched existing issues to avoid duplicates
• I am using the latest version of oh-my-opencode
• I have read the documentation

Bug Description

The agents.sisyphus-junior.model configuration in oh-my-opencode.json is completely ignored. Despite the schema correctly defining sisyphus-junior as a configurable agent, and the code appearing to read the configuration, the actual model used at runtime does not respect the user's configuration.

Analysis using oh-my-opencode codebase:

After analyzing the source code, I found the root cause:

1. Schema layer ✅ - sisyphus-junior is correctly defined in AgentOverridesSchema
2. Agent registration ✅ - createSisyphusJuniorAgentWithOverrides() reads the config correctly
3. Runtime invocation ❌ - When called via delegate_task(category="xxx"), the model resolution logic bypasses the agent config

The problem is in delegate-task/tools.ts:

if (args.category) {
  const resolution = resolveModelWithFallback({
    userModel: userCategories?.[args.category]?.model,  // Priority 1: category model
    categoryDefaultModel: resolved.model ?? sisyphusJuniorModel,  // Priority 3: sisyphusJuniorModel is just fallback!
    fallbackChain: requirement.fallbackChain,  // Priority 2: hardcoded fallbackChain
    availableModels,
    systemDefaultModel,
  })
  agentToUse = SISYPHUS_JUNIOR_AGENT  // Uses sisyphus-junior agent
  categoryModel = ...  // But model comes from category resolution, not agent config!
}

Model resolution priority (current - problematic):

1. userCategories?.[category]?.model - category's model config
2. requirement.fallbackChain - hardcoded fallback chain
3. sisyphusJuniorModel - user's agents.sisyphus-junior.model config (lowest priority!)
4. systemDefaultModel

This means agents.sisyphus-junior.model is effectively useless because it has the lowest priority.

Related issues:

• [Bug]: Sisyphus-Junior agent ignores config and uses Anthropic provider instead of configured Google model #766 (CLOSED but not fixed) - Sisyphus-Junior ignores config and uses Anthropic provider
• [Bug]: Unable to override model via config for Sisyphus-Junior background task #826 (CLOSED but not fixed) - Unable to override model via config for Sisyphus-Junior background task
• [Bug]: delegate_task with category parameter fails with "JSON Parse error: Unexpected EOF" - categories config ignored #1264 (OPEN) - Reports that categories.*.model is ALSO ignored due to uiSelectedModel overriding everything

Important finding from #1264:
Issue #1264 reveals that even configuring categories.*.model doesn't work because uiSelectedModel (main session model) has the HIGHEST priority and overrides ALL agent/category model configurations.

This means both workarounds are blocked:

• ❌ agents.sisyphus-junior.model → bypassed by category resolution
• ❌ categories.*.model → overridden by uiSelectedModel

Steps to Reproduce

1. Configure oh-my-opencode.json:

{
  "agents": {
    "sisyphus-junior": {
      "model": "anthropic/claude-sonnet-4-5"
    }
  }
}

2. Start OpenCode with a different main model (e.g., claude-opus-4-5)

3. Trigger a category-based delegation:

delegate_task(category="quick", load_skills=[], prompt="...", run_in_background=false)

4. Observe that sisyphus-junior does NOT use anthropic/claude-sonnet-4-5

Expected Behavior

When agents.sisyphus-junior.model is configured, the Sisyphus-Junior agent should use that model regardless of:

• Which category is used to spawn it
• What the main session's model is

User-defined agent model configuration should have the HIGHEST priority.

Actual Behavior

The agents.sisyphus-junior.model configuration is ignored. The model is determined by:

1. Main session's model (uiSelectedModel) - if [Bug]: delegate_task with category parameter fails with "JSON Parse error: Unexpected EOF" - categories config ignored #1264's analysis is correct
2. Category's fallback chain
3. Category's default model

User's explicit agent configuration is never applied.

Doctor Output

# bunx oh-my-opencode doctor failed with workspace dependency error
# OpenCode version: 1.1.45
# oh-my-opencode version: latest (3.1.9)

Error Logs

No explicit error - the configuration is silently ignored.

Configuration

{
  "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-opencode/master/assets/oh-my-opencode.schema.json",
  "agents": {
    "sisyphus-junior": {
      "model": "anthropic/claude-sonnet-4-5"
    }
  }
}

Additional Context

Summary of related issues:

Issue	Status	Problem	Fixed?
#766	CLOSED	Sisyphus-Junior ignores config, uses Anthropic	❌ Comments say bug persists
#826	CLOSED	Cannot override model for background tasks	❌ Comments say bug persists in beta 11
#1264	OPEN	uiSelectedModel overrides ALL agent configs	❌

Root cause analysis from #766 comments (by @kassieclaire):

"override configuration from oh-my-opencode.json is being passed through the direct agent override path (via createSisyphusJuniorAgentWithOverrides) rather than through the category-based path"

Suggested fix:

In resolveModelWithFallback(), the priority should be:

// 1. User's explicit agent config (HIGHEST)
if (normalizedUserModel) {
  return { model: normalizedUserModel, source: "override" };
}
// 2. Category config
// 3. Fallback chain
// 4. System default (LOWEST)

Or better: remove uiSelectedModel from subagent model resolution entirely - it should only apply to the main session.

Operating System

Windows

OpenCode Version

1.1.45

[syj925]

It's good in 3.1.7, I've downgraded, hope it's fixed soon

[DevSissi]

not work in 3.1.9