feat(repo): custom agent tool definitions via swamp agent setup

[stack72]

Summary

• Adds swamp agent setup interactive wizard for defining custom AI agent tools
• Custom tools get skills + instructions + gitignore scaffolding, stored in .swamp-custom-tools.yaml at repo root
• swamp repo init --tool <custom-name> works once defined
• Built-in tools (claude, cursor, kiro, etc.) retain full audit/hooks/doctor integration
• Custom tools skip audit subsystems — promoted to built-in when adoption warrants

How it works

1. swamp agent setup asks the tool name, optionally scans an existing repo for config patterns (.windsurf/rules/, AGENTS.md, etc.), then asks where the tool reads instructions from
2. Defaults are derived: skills go to .<name>/skills/, instructions mode (shared vs owned) from the file location
3. Definition saved to .swamp-custom-tools.yaml — committable, copyable between repos
4. swamp repo init --tool <name> resolves custom tools via ToolResolver, copies skills, generates instructions

Architecture

• ToolConfig value object unifies built-in and custom tools at the scaffolding layer
• AiTool union stays closed for built-in exhaustiveness checks
• Boundary types (RepoMarkerData.tools, init/upgrade options/results) widened to string[]
• ToolResolver checks built-in tools first (O(1)), then custom-tools.yaml (lazy-loaded)
• DDD: ToolResolver accepts an injected CustomToolLoader to avoid domain→infrastructure import

New files

• src/domain/repo/custom_tool.ts — types, factories, validation, detection, defaults derivation
• src/domain/repo/tool_resolver.ts — resolution layer (built-in + custom)
• src/infrastructure/persistence/custom_tools_repository.ts — YAML persistence
• src/cli/commands/agent_setup.ts — swamp agent setup/list/rm commands
• Tests for all new modules (41 tests)

Ecosystem research

Researched 12 AI coding tools (Windsurf, Zed, Amp, Aider, Cline, Roo Code, Kilo Code, Trae, Augment, Tabnine, PearAI, Pi). AGENTS.md is converging as the cross-tool standard. Most tools use .<toolname>/rules/ for config. Skills at .<toolname>/skills/ works for tools with native support (Pi, Kilo) and via instructions references for others.

Test plan

• deno check passes
• deno lint clean on new files
• deno fmt applied
• deno run test — 6007 passed, 0 failed
• deno run compile — binary compiles
• Manual: swamp agent setup → define custom tool → swamp repo init --tool <name> → verify scaffolding
• Manual: swamp agent list / swamp agent rm
• Manual: swamp repo init --tool nonexistent → helpful error

🤖 Generated with Claude Code