[Bug]: delegate_task with category parameter fails with "JSON Parse error: Unexpected EOF" - categories config ignored

[64andrewwalker]

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

When using delegate_task with the category parameter (e.g., category="quick"), the task fails with JSON Parse error: Unexpected EOF.

Root cause investigation reveals:

1. The category system ignores the categories configuration in oh-my-opencode.json
2. Instead, it falls back to a hardcoded model (opencode/claude-haiku-4-5) which doesn't exist for users without OpenCode Zen access
3. This causes the agent to fail immediately with EOF error (no response from non-existent model)

Additionally: The disabled_hooks: ["category-skill-reminder"] config option appears to not work - the hook still fires despite being in the disabled list.

Steps to Reproduce

1. Configure oh-my-opencode.json with custom category models:

   {
     "categories": {
       "quick": { "model": "openai/gpt-5.2" },
       "visual-engineering": { "model": "google/antigravity-gemini-3-pro-high" }
     },
     "disabled_hooks": ["category-skill-reminder"]
   }

2. Use delegate_task with category:

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

3. Observe error:

   Send prompt failed
   
   **Error**: JSON Parse error: Unexpected EOF
   **Agent**: sisyphus-junior (category: quick)
   

4. Note that the [Category+Skill Reminder] hook output still appears despite being in disabled_hooks.

Expected Behavior

1. delegate_task(category="quick", ...) should use the model configured in categories.quick.model
2. The disabled_hooks configuration should prevent the specified hooks from running

Actual Behavior

1. Category-based delegation fails with JSON Parse error: Unexpected EOF
2. The system appears to ignore the categories config and fall back to a hardcoded default model
3. disabled_hooks: ["category-skill-reminder"] has no effect - the hook still runs

Workaround

Using subagent_type instead of category works correctly:

delegate_task(subagent_type="general-gemini-3-flash", ...)  # Works
delegate_task(category="quick", ...)                         # Fails

Doctor Output

Installation
────────────────────────────────────────
  ✓ OpenCode Installation → 1.1.42
  ✓ Plugin Registration → Registered (pinned: latest)

Configuration
────────────────────────────────────────
  ✓ Configuration Validity → Valid JSON config

Error Logs

SyntaxError: JSON Parse error: Unexpected EOF
    at <parse> (:0)
    at parse (unknown)
    at processTicksAndRejections (native:7:39)

Configuration

{
  "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-opencode/master/assets/oh-my-opencode.schema.json",
  "disabled_hooks": ["category-skill-reminder"],
  "categories": {
    "quick": { "model": "openai/gpt-5.2" },
    "visual-engineering": { "model": "google/antigravity-gemini-3-pro-high" },
    "ultrabrain": { "model": "openai/gpt-5.2" },
    "artistry": { "model": "google/antigravity-gemini-3-pro-high" },
    "unspecified-low": { "model": "google/antigravity-gemini-3-flash" },
    "unspecified-high": { "model": "google/antigravity-gemini-3-pro-high" },
    "writing": { "model": "google/antigravity-gemini-3-pro-high" }
  },
  "agents": {
    "sisyphus-junior": { "model": "openai/gpt-5.2" }
  }
}

Additional Context

Related issues:

• [Bug]: Agents fallback to default model despite valid configuration for google/antigravity-gemini-3-flash #1253 - Agents fallback to default model despite valid configuration
• Feature Request: Support for custom provider in default categories #1071 - Feature Request: Support for custom provider in default categories
• [Feature]: No config option to disable built-in delegation categories. #1078 - No config option to disable built-in delegation categories

Investigation notes:

• The sisyphus-junior agent is used for category-based delegation
• Both agents.sisyphus-junior.model and categories.*.model configs are ignored
• The fallback chain appears to select opencode/claude-haiku-4-5 regardless of config
• Users without direct Anthropic/OpenCode Zen access cannot use categories at all

Operating System

macOS

OpenCode Version

3.1.7

[64andrewwalker]

Update: This is a regression of #766

After investigating issue #766 (which was marked as fixed by PR #771), I found that:

1. PR Fix session model preservation and plan agent visibility #771 was merged on Jan 14, 2026 and should be included in 3.1.0+
2. The bug persists in 3.1.7 (latest version)
3. User @kassieclaire reported in [Bug]: Sisyphus-Junior agent ignores config and uses Anthropic provider instead of configured Google model #766 comments that "Bug continues to persist in dev build + PR970"

Root Cause Analysis

Looking at the code in oh-my-opencode@3.1.7:

// In createDelegateTask, the resolution path:
const resolution = resolveModelWithFallback({
  userModel: userCategories?.[args.category]?.model ?? sisyphusJuniorModel,
  fallbackChain: requirement.fallbackChain,  // <-- Problem here
  availableModels,
  systemDefaultModel
});

The userCategories?.[args.category]?.model should return "openai/gpt-5.2" from my config, but it's being ignored.

When I check my connected-providers.json:

{"connected": ["openai", "google", "opencode", "quotio"]}

The fallback chain for quick category:

{ providers: ["anthropic", "github-copilot", "opencode"], model: "claude-haiku-4-5" }

Since I have opencode in my connected providers, it picks opencode/claude-haiku-4-5 from the fallback chain INSTEAD of respecting my configured categories.quick.model.

Expected Flow

1. User configures categories.quick.model = "openai/gpt-5.2"
2. userModel should be "openai/gpt-5.2"
3. resolveModelWithFallback should return this as source: "override"
4. Category task should use openai/gpt-5.2

Actual Flow

1. User configures categories.quick.model = "openai/gpt-5.2"
2. userModel is somehow undefined or empty
3. resolveModelWithFallback falls through to fallbackChain
4. Picks opencode/claude-haiku-4-5 (which user doesn't have access to)
5. JSON Parse error: Unexpected EOF

Possible Fix Location

The issue is likely in how pluginConfig.categories is loaded or merged. The configuration loading in loadPluginConfig → loadConfigFromPath2 should be verified.

Related: @kassieclaire's analysis from #766 identified that "override configuration from oh-my-opencode.json is being passed through the direct agent override path rather than through the category-based path."

[64andrewwalker]

CRITICAL UPDATE: Found Another Bug - uiSelectedModel Overrides ALL Agent Configs

I discovered an additional critical bug: The main session's model (uiSelectedModel) overrides ALL agent model configurations, making agents.*.model config completely useless.

Evidence

In my session, I'm using google/antigravity-claude-opus-4-5-thinking-high as the main model.

When I spawn librarian or explore agents, they show:

Librarian · antigravity-claude-opus-4-5-thinking-high · 2m 12s

But my config clearly specifies:

"librarian": { "model": "google/antigravity-gemini-3-pro-high" },
"explore": { "model": "google/antigravity-gemini-3-pro-high" }

Root Cause

In createBuiltinAgents():

const currentModel = config3.model;  // Main session model (opus)
const builtinAgents = await createBuiltinAgents(..., currentModel);

Then in resolveModelWithFallback():

const resolution = resolveModelWithFallback({
  uiSelectedModel,  // = currentModel = OPUS!
  userModel: override?.model,  // = configured gemini-3-pro-high
  ...
});

// BUT uiSelectedModel has HIGHEST priority!
if (normalizedUiModel) {
  return { model: normalizedUiModel, source: "override" };  // Always returns opus!
}
// userModel is NEVER reached!

Impact

1. ALL agents.*.model configurations are ignored
2. Every subagent inherits the main session's model
3. Users cannot configure different models for different agents
4. Expensive models (opus) are used for cheap tasks (explore/librarian)
5. This is a cost and performance issue

Expected Behavior

userModel (from agents.*.model config) should have HIGHER priority than uiSelectedModel (main session model).

Suggested Fix

In resolveModelWithFallback(), swap the priority:

// Check user config FIRST
if (normalizedUserModel) {
  return { model: normalizedUserModel, source: "override" };
}
// THEN check UI selection as fallback
if (normalizedUiModel) {
  return { model: normalizedUiModel, source: "ui-fallback" };
}

Or remove uiSelectedModel from agent resolution entirely - it should only apply to the main session, not subagents.

[syj925]

+1

[lockcmd]

+1

[DevSissi]

+1 sisyphus-junior cant modified by omo.json

[junelee220]

+1