refactor: extract 11 MCP tool handlers into src/tools/

[PatrickSys]

Summary

• Splits src/index.ts (2,227 lines) into 13 focused modules under src/tools/
• src/index.ts is now pure MCP protocol wiring (~607 lines) — no business logic
• All 11 tool handlers are extracted verbatim; no behavior changes

Changes

New files — src/tools/

• types.ts — shared ToolContext, ToolResponse, ToolPaths, IndexState interfaces
• index.ts — TOOLS array aggregator + dispatchTool() router
• One file per tool: search-codebase, get-codebase-metadata, get-indexing-status, refresh-index, get-style-guide, get-team-patterns, get-symbol-references, get-component-usage, detect-circular-dependencies, remember, get-memory

Modified — src/index.ts

• Removes inline TOOLS array (~260 lines) and CallToolRequestSchema switch statement (~1,390 lines)
• Replaces with a single dispatchTool() call via injected ToolContext

New test — tests/tools/dispatch.test.ts

• 6 tests: verifies all 11 tools exported, unique names, schemas present, routing works, error handling for unknown tools

Test plan

• pnpm build — zero TypeScript errors
• pnpm test — all 201 tests pass (195 pre-existing + 6 new)
• All 11 tool schemas verified against original src/index.ts via git show HEAD
• All handler implementations verified as exact copies with context injection substitutions

[PatrickSys]

@codex review

[greptile-apps]

Greptile Summary

Successfully extracted 11 MCP tool handlers from the monolithic src/index.ts (2,227 lines) into focused, single-responsibility modules under src/tools/. The main index file is now reduced to ~607 lines and focuses purely on MCP protocol wiring, following the project constraint that "src/index.ts is routing and protocol. No business logic" (AGENTS.md line 127).

Key improvements:

• Each tool now has its own file with definition (Tool schema) and handle (async handler) exports
• Introduced src/tools/types.ts with shared ToolContext, ToolResponse, ToolPaths, and IndexState interfaces
• Created src/tools/index.ts aggregator that exports TOOLS array and dispatchTool() router
• Replaced massive switch statement in src/index.ts with single dispatchTool() call via injected context
• Added 6 integration tests in tests/tools/dispatch.test.ts validating tool routing and error handling

Code preservation:

• All 11 tool handlers preserve identical logic from original implementation
• Tool definitions (schemas, descriptions) remain unchanged
• Error handling and response formats are consistent

This refactoring improves maintainability without changing runtime behavior, aligning with AGENTS.md Rule 1: "Janitor > Visionary - Success = noise removed, not complexity added."

Confidence Score: 5/5

• This PR is safe to merge with no risk
• Clean refactoring that extracts tool handlers into focused modules without changing runtime behavior. All tool logic is preserved identically, new abstractions (ToolContext, dispatchTool) are well-defined, and integration tests validate the routing mechanism. Follows AGENTS.md constraint that src/index.ts should be "routing and protocol. No business logic."
• No files require special attention

Important Files Changed

Filename	Overview
src/tools/types.ts	New types file defining ToolContext, ToolResponse, ToolPaths, and IndexState interfaces for tool handlers
src/tools/index.ts	Tool aggregator exporting TOOLS array and dispatchTool() router function
src/index.ts	Reduced from 2,227 to ~607 lines by extracting tool handlers; now focuses on MCP protocol wiring
tests/tools/dispatch.test.ts	New integration tests (6 tests) validating tool routing and dispatcher functionality

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[src/index.ts<br/>MCP Server] -->|imports| B[src/tools/index.ts]
    B -->|exports| C[TOOLS array]
    B -->|exports| D[dispatchTool function]
    B -->|imports| E[src/tools/types.ts]
    
    E -->|defines| F[ToolContext interface]
    E -->|defines| G[ToolResponse interface]
    E -->|defines| H[ToolPaths interface]
    
    B -->|aggregates| I[11 Tool Handlers]
    
    I --> J1[search-codebase.ts]
    I --> J2[get-codebase-metadata.ts]
    I --> J3[get-indexing-status.ts]
    I --> J4[refresh-index.ts]
    I --> J5[get-style-guide.ts]
    I --> J6[get-team-patterns.ts]
    I --> J7[get-symbol-references.ts]
    I --> J8[get-component-usage.ts]
    I --> J9[detect-circular-dependencies.ts]
    I --> J10[remember.ts]
    I --> J11[get-memory.ts]
    
    J1 -->|exports| K1[definition + handle]
    J2 -->|exports| K2[definition + handle]
    J3 -->|exports| K3[definition + handle]
    
    A -->|CallToolRequestSchema| L[Request Handler]
    L -->|creates| F
    L -->|calls| D
    D -->|routes to| I
    
    M[tests/tools/dispatch.test.ts] -.->|validates| B
    M -.->|validates| D

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[Copilot]

Pull request overview

This PR refactors the monolithic src/index.ts file (originally 2,227 lines) by extracting 11 MCP tool handlers into separate, focused modules under src/tools/. The refactoring reduces src/index.ts to ~607 lines of pure MCP protocol wiring while maintaining all existing functionality.

Changes:

• Extracted 11 tool handlers from src/index.ts into dedicated files in src/tools/
• Created src/tools/types.ts to define shared ToolContext, ToolResponse, and ToolPaths interfaces
• Created src/tools/index.ts as an aggregator with TOOLS array and dispatchTool() router
• Updated src/index.ts to use dependency injection via ToolContext for tool dispatching
• Added integration tests for tool routing in tests/tools/dispatch.test.ts

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tools/types.ts	Defines shared types for tool handlers (ToolContext, ToolResponse, ToolPaths, IndexState)
src/tools/index.ts	Aggregates all 11 tools and provides dispatchTool() routing logic
src/tools/search-codebase.ts	Extracted search_codebase tool with preflight checks and evidence gating
src/tools/get-codebase-metadata.ts	Extracted get_codebase_metadata tool for framework and dependency info
src/tools/get-indexing-status.ts	Extracted get_indexing_status tool for index state and progress
src/tools/refresh-index.ts	Extracted refresh_index tool for manual re-indexing
src/tools/get-style-guide.ts	Extracted get_style_guide tool for documentation querying
src/tools/get-team-patterns.ts	Extracted get_team_patterns tool for pattern recommendations
src/tools/get-symbol-references.ts	Extracted get_symbol_references tool for symbol usage tracking
src/tools/get-component-usage.ts	Extracted get_component_usage tool for library/component usage
src/tools/detect-circular-dependencies.ts	Extracted detect_circular_dependencies tool for cycle detection
src/tools/remember.ts	Extracted remember tool for recording team conventions
src/tools/get-memory.ts	Extracted get_memory tool for retrieving recorded conventions
src/index.ts	Reduced to MCP protocol wiring, imports TOOLS and dispatchTool from src/tools/
tests/tools/dispatch.test.ts	Added 6 integration tests for tool routing and structure validation

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