[Bug]: Oversized System Prompt

[jz315]

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 or asked an AI coding agent with this project's GitHub URL loaded and couldn't find the answer

Bug Description

I'm using Opus 4.6 and found that the initial system prompt has 60,000 tokens. Is this a bug I've encountered, or is it really that large?

Steps to Reproduce

1

Expected Behavior

1

Actual Behavior

1

Doctor Output

1

Error Logs

Configuration

Additional Context

No response

Operating System

macOS

OpenCode Version

latest

[Luodian]

Root Cause Analysis

I investigated this and found the oversized system prompt is caused by skill list duplication across multiple tool descriptions and the system prompt itself. Here's the breakdown:

Where skills are listed (3 times)

Location	Tool	What it lists
1. skill tool description	mcp_skill	Full <available_skills> XML with every skill name + description
2. slashcommand tool description	mcp_slashcommand	Full <available_skills> with every skill + command name + description
3. Sisyphus system prompt	Delegation table	Full skill name + description table for "User-Installed Skills"

Impact

With ~80 installed skills, each entry ~30 tokens:

• Per list: ~2,400 tokens
• 3 copies: ~7,200 tokens wasted on pure duplication
• Plus boilerplate around each list

This is a significant chunk of the 60K system prompt.

Proposed Fix

1. Merge skill tool into slashcommand - slashcommand is already a superset of skill (it handles both skills AND commands). Removing the separate skill tool eliminates one full copy of the skill list.

2. Remove skill list from Sisyphus system prompt - The delegation table repeats the skill list a third time. Replace with a reference: "See skills listed in the slashcommand tool description."

This would reduce the skill list from 3 copies to 1, saving ~4,800+ tokens for a user with 80 skills.

I'll submit a PR with this fix.