[Refactoring] Audit and Clean tool-handler.ts - Remove Dead Code

[gloomcheng]

Problem

src/core/mcp/handlers/tool-handler.ts is 741 lines and may contain dead code after Issue #11 refactoring.

Status: After splitting StableWorkflowHandler into domain-based handlers, tool-handler.ts might be deprecated or need restructuring.

Investigation Needed

1. Is tool-handler.ts still used?

   • Check all imports of ToolHandler
   • Identify remaining responsibilities

2. If used:

   • What functionality does it provide?
   • Can it be split by domain?
   • Does it overlap with new handlers?

3. If unused:

   • Mark as deprecated
   • Create migration plan
   • Remove safely

Acceptance Criteria

• Usage audit complete
• Dead code identified and removed
• If kept: file split or reduced to <400 lines
• If removed: all references migrated
• Build passing, tests green
• Documentation updated

Priority

🔴 High - Technical debt clarity

Effort Estimate

1 day

[gloomcheng]

Implemented in commit c2c1820

Audit Results

• ToolHandler: Instantiated but never used - all methods duplicated in new decorator-based handlers
• Cascading dead code: handoff-service.ts and text-processor.ts only used by ToolHandler

Removed

• tool-handler.ts (741 lines)
• handoff-service.ts (177 lines)
• text-processor.ts (160 lines)
• Empty validation/ directory

Total: 1081 lines of dead code removed

Build passes ✅