[FEATURE] Configurable per-tool-type display policy (show/collapse/hide) #35193

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Related existing issues

• [FEATURE]: Collapse skill body in user message #33980 — Hiding skill body in user message
• [FEATURE]: Add keyboard shortcut to toggle tool output Click to expand #14511 — Keyboard shortcut to toggle Click to expand

Describe the enhancement you want to request

Currently, OpenCode applies a single display strategy to all tool outputs — either show everything (default) or hide everything (/details toggle). There is no way to control display behavior per tool type.

For example:

• Skill tools dump large instruction bodies into user messages with no way to collapse them ([FEATURE]: Collapse skill body in user message #33980).
• MCP tools can be chatty internal plumbing that users don't need to see every time.
• todowrite is already hardcoded as hidden (HIDDEN_TOOLS), but users cannot customize this.
• edit/write/bash are the ones users typically want to see expanded.

I'd like a configurable per-tool-type display policy so each tool type can have its own default rendering: fully expanded, collapsed (click to expand), or completely hidden.

Proposed design

Add a tool_display section to opencode.json:

{
  "tool_display": {
    "default": "expanded",     // fallback for tools without an override
    "overrides": {
      "skill": "collapsed",    // skill calls: collapsed by default, expandable on click
      "mcp__*": "collapsed",   // all MCP tools: collapsed by default (glob pattern)
      "todowrite": "hidden",   // fully hidden (replaces current hardcoded HIDDEN_TOOLS)
      "edit": "expanded",      // always show edits
      "write": "expanded",     // always show writes
      "bash": "expanded"       // always show terminal output
    }
  }
}

Three display modes:

The overrides map supports glob patterns so that MCP tools (which have dynamic names like mcp__github__search) can be grouped under one rule.

Why this matters

• Replaces the hardcoded HIDDEN_TOOLS = new Set(["todowrite"]) in packages/session-ui/src/components/message-part.tsx with a user-configurable system.
• Solves [FEATURE]: Collapse skill body in user message #33980 (skill body noise) without a special-case component.
• MCP ecosystem is growing fast — users need control over which MCP tool outputs they see.
• Complements [FEATURE]: Add keyboard shortcut to toggle tool output Click to expand #14511: collapsed tools can be expanded via keyboard shortcut.
• Backward compatible: default behavior is unchanged for users who don't configure it.