Load agents from OpenCode config files instead of VS Code settings

[marchingphoenix]

Summary

This PR refactors agent configuration to read directly from OpenCode configuration files (opencode.json / opencode.jsonc) instead of VS Code settings. The extension now searches for config in the same locations as the OpenCode CLI: explicit path → workspace root → ~/.config/opencode/. It also discovers markdown-based agents from .opencode/agents/ directories and provides built-in fallback agents (build, plan).

Key Changes

• New opencodeConfigReader module — Implements config file discovery and parsing:

  • resolveConfigSearchPaths() — Builds ordered search paths with ~ expansion
  • readOpenCodeConfig() — Reads and parses opencode.json / opencode.jsonc with JSONC comment stripping
  • readMarkdownAgents() — Discovers markdown-based agents from .opencode/agents/
  • loadAgentsFromOpenCodeConfig() — Orchestrates loading from all sources with proper precedence

• Updated AgentRegistry — Now loads agents from OpenCode config files:

  • Reads from opencodeConfigPath VS Code setting (new), workspace root, or global ~/.config/opencode/
  • Watches for changes to opencode.json / opencode.jsonc files and auto-reloads
  • Removed hardcoded agent definitions from VS Code settings
  • Falls back to built-in agents (build, plan) when no config exists

• Agent configuration enhancements:

  • Added mode field to AgentConfig to distinguish primary agents from subagents
  • Agents now parse provider/model format (e.g., anthropic/claude-sonnet-4-20250514)
  • Support for agent descriptions and custom modes from config

• Updated chat participant — /agents command now groups agents by primary vs. subagent and shows they're loaded from config files

• Documentation — Expanded README with agent configuration guide, search order, config file format examples, and markdown agent discovery

• Settings changes:

  • Added opencode-devcontainer.opencodeConfigPath setting for explicit config path
  • Removed opencode-devcontainer.agents and opencode-devcontainer.defaultAgent settings (now read from config files)

Implementation Details

• JSONC parsing strips line comments (//) and block comments (/* */) before JSON parsing
• Model strings without / default to provider: "unknown"
• Agent IDs are prettified to display names (kebab-case → Title Case)
• Markdown agents use filename (minus .md) as ID and first non-empty line as description
• Built-in agents are always present but can be overridden by config definitions
• File system watcher monitors workspace for config changes to trigger auto-reload

https://claude.ai/code/session_01BCbPTVpavaPCg2iYsCizE6