feat: sin config — Unified configuration management

[Delqhi]

Description

Add a sin config command for unified management of all SIN-Code configuration files, eliminating manual JSON/YAML editing.

Current Pain Point

Users must manually edit multiple config files:

• ~/.config/opencode/opencode.json — providers, models, MCP servers, agents, skills, permissions
• ~/.config/opencode/skills/*.md — skill configurations
• ~/.pcpm/ — project brain files
• AGENTS.md — global/project rules
• MCP server env vars scattered across shell profiles

Requirements

sin config show                          # Show all effective config (merged view)
sin config show --source opencode        # Show only opencode.json
sin config show --source skills          # Show only skill configs
sin config get providers.fireworks-ai.models  # Get nested value
sin config set providers.fireworks-ai.models.gpt-4o.max_tokens 8192
sin config add mcp-server myserver '{"command": "uvx myserver-mcp"}'
sin config remove mcp-server myserver
sin config add skill my-skill --from-github OpenSIN-Code/SIN-Code-MySkill
sin config enable skill my-skill
sin config disable skill my-skill
sin config migrate --from-version 1.0.0  # Auto-migrate config schema
sin config validate                      # Validate all configs against schemas
sin config backup                        # Backup all configs to ~/.config/sin/backups/
sin config restore <backup-file>         # Restore from backup
sin config edit                          # Open in $EDITOR (opencode.json)

Configuration Sources (Priority Order)

1. Project-local: .sin/config.json (highest priority)
2. Global: ~/.config/sin/config.json
3. opencode: ~/.config/opencode/opencode.json
4. Skills: ~/.config/opencode/skills/*.md
5. Project brain: ~/.pcpm/
6. Defaults: Built-in defaults

Features

• Schema validation: JSON Schema for each config source
• Merge logic: Deep merge with clear precedence
• Diff view: sin config diff shows changes vs defaults
• Import/Export: sin config export > config.json, sin config import < config.json
• Secrets handling: Never print API keys (show as ***), use Infisical/Keyring for storage
• Completion: Shell completion for config paths

Acceptance Criteria

• sin config show displays merged config from all sources
• sin config get/set works with dot-notation paths
• sin config add/remove mcp-server modifies opencode.json correctly
• sin config validate catches schema violations
• sin config backup/restore works round-trip
• Secrets never leaked in output (masked as ***)
• Shell completion for config keys

Priority

HIGH — Eliminates #1 configuration friction; currently 100% manual JSON editing

[Delqhi]

Not addressed in v3.0.0–v3.2.0 (focus was on the agent loop, verification gate, hooks, slash commands). Remaining work for future release train.

[Delqhi]

Status (2026-06-12, post-v3.5.0)

Priority: MEDIUM — needed before non-developers can use sin-code.

Current state

• ✅ config subcommand EXISTS (sin-code config)
• ✅ Manages ~/.config/sin-code/ and ./.sin/config.json
• ❌ No web UI for non-CLI users
• ❌ No env-var-only config fallback
• ❌ No config validation/preview

What still needs work

• sin-code config init — interactive wizard
• sin-code config show — pretty-print current config
• sin-code config validate — schema check before use
• Migration path: v0 config files → v3.5.0 schema

Cross-refs

• AGENTS.md §7 (configuration contract — partial)
• .goreleaser.yaml (binary defaults)
• Sister-issue: [v3.6.0] feat: WebUI-v2 backend API (sessions/knowledge/chat-with-SSE) #52 (WebUI-v2 API — config surface)

[Delqhi]

Update (2026-06-12, post-v3.6.0)

Status: in v3.7.0 scope. Tracking as sub-item of the v3.7.0 metaissue (#57).

What exists today (v3.6.0)

• ✅ sin-code config subcommand exists (cmd/sin-code/internal/config.go)
• ✅ Manages ~/.config/sin-code/ and ./.sin/config.json
• ❌ No init (interactive wizard)
• ❌ No show (pretty-print current effective config)
• ❌ No validate (schema check before use)
• ❌ No env-var-only config fallback

Recommended fix (1-2 days)

• Add config init — interactive prompts for: LLM base URL, API key env, verify mode, MCP servers
• Add config show — pretty-print the deep-merged effective config (user+project)
• Add config validate — schema check that all required fields are present
• Document the 3-layer config stack: env vars > project > user (with merge order)