tool-selection

name	tool-selection
description	Select the right typegraph-mcp tool for TypeScript navigation. Trigger when finding definitions, references, types, exploring code structure, preparing refactors, or any task where you would otherwise use grep/glob for TypeScript symbols.

TypeGraph Tool Selection Guide

Select the right typegraph-mcp tool for the task at hand. These tools provide type-aware TypeScript navigation — use them instead of grep/glob for any TypeScript codebase navigation.

When to Activate

• Navigating TypeScript code (finding definitions, references, types)
• Exploring unfamiliar code or understanding how modules connect
• Preparing to refactor or modify TypeScript symbols
• Answering questions about code structure, dependencies, or impact
• Any task where you would otherwise use grep/glob to find TypeScript symbols

Tool Selection Decision Tree

"Where is X defined?"

Use ts_definition with the file + symbol name (or line+column). Resolves through barrel files, re-exports, and project references.

"I don't know which file X is in"

Use ts_navigate_to with just the symbol name. Searches the entire project. For object literal keys (like RPC handlers), also pass a file hint.

"What is the type of X?"

Use ts_type_info — returns the same info as hovering in VS Code. Includes documentation.

"What are all the exports of this file?"

Use ts_module_exports — lists all exported symbols with their resolved types.

If the file is a top-level barrel (index.ts, re-export hub), the result may be sparse or unhelpful for architecture discovery. For quick project insight, prefer composition modules such as entrypoints, routers, handler modules, service composition roots, or API modules that wire concrete behavior together.

"Where is X used?"

Use ts_references for all semantic references. Unlike grep, this returns only real code references, not string matches in comments or unrelated variables.

"What breaks if I change X?"

Use ts_blast_radius — finds all usage sites and groups them by file. This is the starting point for impact analysis.

"How does the code get from A to B?"

Use ts_trace_chain — follows go-to-definition hops automatically, building a call chain. Stops at the bottom of the chain or at node_modules boundaries.

"What does this file import?"

Use ts_dependency_tree for the transitive import tree. Set depth to limit traversal.

"What imports this file?"

Use ts_dependents — all files that depend on a given file, grouped by package. Shows both direct and transitive dependents.

"Are there circular imports?"

Use ts_import_cycles — detects strongly connected components. Filter by file or package.

"How does module A reach module B?"

Use ts_shortest_path — finds the shortest import path between two files in the module graph.

"What's the neighborhood around these files?"

Use ts_subgraph — extracts nodes and edges around seed files, expanding by depth in any direction (imports, dependents, or both).

"How coupled is this module?"

Use ts_module_boundary — analyzes incoming/outgoing edges, shared dependencies, and computes an isolation score.

Key Principles

1. Always prefer ts_ tools over grep/glob* for TypeScript navigation. They resolve through barrel files, re-exports, and project references.
2. Start narrow, expand if needed. Use ts_definition or ts_find_symbol first. Only use ts_navigate_to (project-wide search) when you don't know the file.
3. Combine tools for workflows. Impact analysis = ts_blast_radius + ts_dependents. Refactor safety = ts_trace_chain + ts_import_cycles.
4. Graph queries are instant (~0.1ms). Point queries are fast (~2-50ms). Don't hesitate to use them liberally.
5. First query may be slow (~2s) as tsserver warms up. All subsequent queries are fast.
6. For fast architecture reads, start at composition modules, not barrels. Barrels are useful for API shape, but entrypoints and composition roots tell you how the system is actually wired.

Tool Reference

Tool	Input	Best For
ts_find_symbol	file + symbol name	Locating a symbol when you know the file
ts_definition	file + symbol (or line+col)	Go-to-definition through any indirection
ts_references	file + symbol (or line+col)	All semantic references to a symbol
ts_type_info	file + symbol (or line+col)	Type signature and documentation
ts_navigate_to	symbol name (+ optional file)	Project-wide symbol search
ts_trace_chain	file + symbol + maxHops	Following a call chain to implementation
ts_blast_radius	file + symbol	Impact analysis for changes
ts_module_exports	file	Listing a module's public API
ts_dependency_tree	file (+ depth)	What a file depends on
ts_dependents	file (+ depth)	What depends on a file
ts_import_cycles	optional file/package filter	Circular dependency detection
ts_shortest_path	from file + to file	Import path between two files
ts_subgraph	seed files + depth + direction	Neighborhood extraction
ts_module_boundary	file list	Module coupling analysis