This commit is contained in:
Colby McHenry
2026-01-18 16:25:00 -06:00
parent 08ccabb5a9
commit cc6e7a5c89
57 changed files with 23315 additions and 1 deletions
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/**
* CodeGraph MCP Server
*
* Model Context Protocol server that exposes CodeGraph functionality
* as tools for AI assistants like Claude.
*
* @module mcp
*
* @example
* ```typescript
* import { MCPServer } from 'codegraph';
*
* const server = new MCPServer('/path/to/project');
* await server.start();
* ```
*/
import CodeGraph from '../index';
import { StdioTransport, JsonRpcRequest, JsonRpcNotification, ErrorCodes } from './transport';
import { tools, ToolHandler } from './tools';
/**
* MCP Server Info
*/
const SERVER_INFO = {
name: 'codegraph',
version: '0.1.0',
};
/**
* MCP Protocol Version
*/
const PROTOCOL_VERSION = '2024-11-05';
/**
* MCP Server for CodeGraph
*
* Implements the Model Context Protocol to expose CodeGraph
* functionality as tools that can be called by AI assistants.
*/
export class MCPServer {
private transport: StdioTransport;
private cg: CodeGraph | null = null;
private toolHandler: ToolHandler | null = null;
private projectPath: string;
constructor(projectPath: string) {
this.projectPath = projectPath;
this.transport = new StdioTransport();
}
/**
* Start the MCP server
*/
async start(): Promise<void> {
// Open CodeGraph for the project
if (!CodeGraph.isInitialized(this.projectPath)) {
throw new Error(`CodeGraph not initialized in ${this.projectPath}. Run 'codegraph init' first.`);
}
this.cg = await CodeGraph.open(this.projectPath);
this.toolHandler = new ToolHandler(this.cg);
// Start listening for messages
this.transport.start(this.handleMessage.bind(this));
// Keep the process running
process.on('SIGINT', () => this.stop());
process.on('SIGTERM', () => this.stop());
}
/**
* Stop the server
*/
stop(): void {
if (this.cg) {
this.cg.close();
this.cg = null;
}
this.transport.stop();
process.exit(0);
}
/**
* Handle incoming JSON-RPC messages
*/
private async handleMessage(message: JsonRpcRequest | JsonRpcNotification): Promise<void> {
// Check if it's a request (has id) or notification (no id)
const isRequest = 'id' in message;
switch (message.method) {
case 'initialize':
if (isRequest) {
await this.handleInitialize(message as JsonRpcRequest);
}
break;
case 'initialized':
// Notification that client has finished initialization
// No action needed - the client is ready
break;
case 'tools/list':
if (isRequest) {
await this.handleToolsList(message as JsonRpcRequest);
}
break;
case 'tools/call':
if (isRequest) {
await this.handleToolsCall(message as JsonRpcRequest);
}
break;
case 'ping':
if (isRequest) {
this.transport.sendResult((message as JsonRpcRequest).id, {});
}
break;
default:
if (isRequest) {
this.transport.sendError(
(message as JsonRpcRequest).id,
ErrorCodes.MethodNotFound,
`Method not found: ${message.method}`
);
}
}
}
/**
* Handle initialize request
*/
private async handleInitialize(request: JsonRpcRequest): Promise<void> {
// We accept the client's protocol version but respond with our supported version
this.transport.sendResult(request.id, {
protocolVersion: PROTOCOL_VERSION,
capabilities: {
tools: {},
},
serverInfo: SERVER_INFO,
});
}
/**
* Handle tools/list request
*/
private async handleToolsList(request: JsonRpcRequest): Promise<void> {
this.transport.sendResult(request.id, {
tools: tools,
});
}
/**
* Handle tools/call request
*/
private async handleToolsCall(request: JsonRpcRequest): Promise<void> {
const params = request.params as {
name: string;
arguments?: Record<string, unknown>;
};
if (!params || !params.name) {
this.transport.sendError(
request.id,
ErrorCodes.InvalidParams,
'Missing tool name'
);
return;
}
const toolName = params.name;
const toolArgs = params.arguments || {};
// Validate tool exists
const tool = tools.find(t => t.name === toolName);
if (!tool) {
this.transport.sendError(
request.id,
ErrorCodes.InvalidParams,
`Unknown tool: ${toolName}`
);
return;
}
// Execute the tool
if (!this.toolHandler) {
this.transport.sendError(
request.id,
ErrorCodes.InternalError,
'Server not initialized'
);
return;
}
const result = await this.toolHandler.execute(toolName, toolArgs);
this.transport.sendResult(request.id, result);
}
}
// Export for use in CLI
export { StdioTransport } from './transport';
export { tools, ToolHandler } from './tools';
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/**
* MCP Tool Definitions
*
* Defines the tools exposed by the CodeGraph MCP server.
*/
import CodeGraph from '../index';
import type { Node, SearchResult, Subgraph, TaskContext, NodeKind } from '../types';
/**
* MCP Tool definition
*/
export interface ToolDefinition {
name: string;
description: string;
inputSchema: {
type: 'object';
properties: Record<string, PropertySchema>;
required?: string[];
};
}
interface PropertySchema {
type: string;
description: string;
enum?: string[];
default?: unknown;
}
/**
* Tool execution result
*/
export interface ToolResult {
content: Array<{
type: 'text';
text: string;
}>;
isError?: boolean;
}
/**
* All CodeGraph MCP tools
*/
export const tools: ToolDefinition[] = [
{
name: 'codegraph_search',
description: 'Search for code symbols (functions, classes, methods) by name or semantic similarity. Returns matching nodes with their locations and signatures.',
inputSchema: {
type: 'object',
properties: {
query: {
type: 'string',
description: 'Search query - can be a symbol name or natural language description',
},
kind: {
type: 'string',
description: 'Filter by node kind',
enum: ['function', 'method', 'class', 'interface', 'type', 'variable', 'route', 'component'],
},
limit: {
type: 'number',
description: 'Maximum number of results to return (default: 10)',
default: 10,
},
},
required: ['query'],
},
},
{
name: 'codegraph_context',
description: 'Build relevant code context for a task or issue. Finds related symbols and their code, formatted for understanding the codebase.',
inputSchema: {
type: 'object',
properties: {
task: {
type: 'string',
description: 'Description of the task, bug, or feature to build context for',
},
maxNodes: {
type: 'number',
description: 'Maximum number of code symbols to include (default: 20)',
default: 20,
},
includeCode: {
type: 'boolean',
description: 'Include full code snippets (default: true)',
default: true,
},
},
required: ['task'],
},
},
{
name: 'codegraph_callers',
description: 'Find all functions/methods that call a specific symbol. Useful for understanding usage patterns and impact of changes.',
inputSchema: {
type: 'object',
properties: {
symbol: {
type: 'string',
description: 'Name of the function, method, or class to find callers for',
},
limit: {
type: 'number',
description: 'Maximum number of callers to return (default: 20)',
default: 20,
},
},
required: ['symbol'],
},
},
{
name: 'codegraph_callees',
description: 'Find all functions/methods that a specific symbol calls. Useful for understanding dependencies and code flow.',
inputSchema: {
type: 'object',
properties: {
symbol: {
type: 'string',
description: 'Name of the function, method, or class to find callees for',
},
limit: {
type: 'number',
description: 'Maximum number of callees to return (default: 20)',
default: 20,
},
},
required: ['symbol'],
},
},
{
name: 'codegraph_impact',
description: 'Analyze the impact radius of changing a symbol. Shows what code could be affected by modifications.',
inputSchema: {
type: 'object',
properties: {
symbol: {
type: 'string',
description: 'Name of the symbol to analyze impact for',
},
depth: {
type: 'number',
description: 'How many levels of dependencies to traverse (default: 2)',
default: 2,
},
},
required: ['symbol'],
},
},
{
name: 'codegraph_node',
description: 'Get detailed information about a specific code symbol, including its full code.',
inputSchema: {
type: 'object',
properties: {
symbol: {
type: 'string',
description: 'Name of the symbol to get details for',
},
includeCode: {
type: 'boolean',
description: 'Include full source code (default: true)',
default: true,
},
},
required: ['symbol'],
},
},
{
name: 'codegraph_status',
description: 'Get the status of the CodeGraph index, including statistics about indexed files, nodes, and edges.',
inputSchema: {
type: 'object',
properties: {},
},
},
];
/**
* Tool handler that executes tools against a CodeGraph instance
*/
export class ToolHandler {
constructor(private cg: CodeGraph) {}
/**
* Execute a tool by name
*/
async execute(toolName: string, args: Record<string, unknown>): Promise<ToolResult> {
try {
switch (toolName) {
case 'codegraph_search':
return await this.handleSearch(args);
case 'codegraph_context':
return await this.handleContext(args);
case 'codegraph_callers':
return await this.handleCallers(args);
case 'codegraph_callees':
return await this.handleCallees(args);
case 'codegraph_impact':
return await this.handleImpact(args);
case 'codegraph_node':
return await this.handleNode(args);
case 'codegraph_status':
return await this.handleStatus();
default:
return this.errorResult(`Unknown tool: ${toolName}`);
}
} catch (err) {
return this.errorResult(`Tool execution failed: ${err instanceof Error ? err.message : String(err)}`);
}
}
/**
* Handle codegraph_search
*/
private async handleSearch(args: Record<string, unknown>): Promise<ToolResult> {
const query = args.query as string;
const kind = args.kind as string | undefined;
const limit = (args.limit as number) || 10;
const results = this.cg.searchNodes(query, {
limit,
kinds: kind ? [kind as NodeKind] : undefined,
});
if (results.length === 0) {
return this.textResult(`No results found for "${query}"`);
}
const formatted = this.formatSearchResults(results);
return this.textResult(formatted);
}
/**
* Handle codegraph_context
*/
private async handleContext(args: Record<string, unknown>): Promise<ToolResult> {
const task = args.task as string;
const maxNodes = (args.maxNodes as number) || 20;
const includeCode = args.includeCode !== false;
const context = await this.cg.buildContext(task, {
maxNodes,
includeCode,
format: 'markdown',
});
// buildContext returns string when format is 'markdown'
if (typeof context === 'string') {
return this.textResult(context);
}
// If it returns TaskContext, format it
return this.textResult(this.formatTaskContext(context));
}
/**
* Handle codegraph_callers
*/
private async handleCallers(args: Record<string, unknown>): Promise<ToolResult> {
const symbol = args.symbol as string;
const limit = (args.limit as number) || 20;
// First find the node by name
const results = this.cg.searchNodes(symbol, { limit: 1 });
if (results.length === 0 || !results[0]) {
return this.textResult(`Symbol "${symbol}" not found in the codebase`);
}
const node = results[0].node;
const callers = this.cg.getCallers(node.id);
if (callers.length === 0) {
return this.textResult(`No callers found for "${symbol}"`);
}
// Extract just the nodes from the { node, edge } tuples
const callerNodes = callers.slice(0, limit).map(c => c.node);
const formatted = this.formatNodeList(callerNodes, `Callers of ${symbol}`);
return this.textResult(formatted);
}
/**
* Handle codegraph_callees
*/
private async handleCallees(args: Record<string, unknown>): Promise<ToolResult> {
const symbol = args.symbol as string;
const limit = (args.limit as number) || 20;
// First find the node by name
const results = this.cg.searchNodes(symbol, { limit: 1 });
if (results.length === 0 || !results[0]) {
return this.textResult(`Symbol "${symbol}" not found in the codebase`);
}
const node = results[0].node;
const callees = this.cg.getCallees(node.id);
if (callees.length === 0) {
return this.textResult(`No callees found for "${symbol}"`);
}
// Extract just the nodes from the { node, edge } tuples
const calleeNodes = callees.slice(0, limit).map(c => c.node);
const formatted = this.formatNodeList(calleeNodes, `Callees of ${symbol}`);
return this.textResult(formatted);
}
/**
* Handle codegraph_impact
*/
private async handleImpact(args: Record<string, unknown>): Promise<ToolResult> {
const symbol = args.symbol as string;
const depth = (args.depth as number) || 2;
// First find the node by name
const results = this.cg.searchNodes(symbol, { limit: 1 });
if (results.length === 0 || !results[0]) {
return this.textResult(`Symbol "${symbol}" not found in the codebase`);
}
const node = results[0].node;
const impact = this.cg.getImpactRadius(node.id, depth);
const formatted = this.formatImpact(symbol, impact);
return this.textResult(formatted);
}
/**
* Handle codegraph_node
*/
private async handleNode(args: Record<string, unknown>): Promise<ToolResult> {
const symbol = args.symbol as string;
const includeCode = args.includeCode !== false;
// Find the node by name
const results = this.cg.searchNodes(symbol, { limit: 1 });
if (results.length === 0 || !results[0]) {
return this.textResult(`Symbol "${symbol}" not found in the codebase`);
}
const node = results[0].node;
let code: string | null = null;
if (includeCode) {
code = await this.cg.getCode(node.id);
}
const formatted = this.formatNodeDetails(node, code);
return this.textResult(formatted);
}
/**
* Handle codegraph_status
*/
private async handleStatus(): Promise<ToolResult> {
const stats = this.cg.getStats();
const lines: string[] = [
'## CodeGraph Status',
'',
`**Files indexed:** ${stats.fileCount}`,
`**Total nodes:** ${stats.nodeCount}`,
`**Total edges:** ${stats.edgeCount}`,
`**Database size:** ${(stats.dbSizeBytes / 1024 / 1024).toFixed(2)} MB`,
'',
'### Nodes by Kind:',
];
for (const [kind, count] of Object.entries(stats.nodesByKind)) {
if ((count as number) > 0) {
lines.push(`- ${kind}: ${count}`);
}
}
lines.push('', '### Languages:');
for (const [lang, count] of Object.entries(stats.filesByLanguage)) {
if ((count as number) > 0) {
lines.push(`- ${lang}: ${count}`);
}
}
return this.textResult(lines.join('\n'));
}
// =========================================================================
// Formatting helpers
// =========================================================================
private formatSearchResults(results: SearchResult[]): string {
const lines: string[] = [`## Search Results (${results.length} found)`, ''];
for (const result of results) {
const { node, score } = result;
const location = node.startLine ? `:${node.startLine}` : '';
lines.push(`### ${node.name} (${node.kind})`);
lines.push(`**Location:** ${node.filePath}${location}`);
lines.push(`**Score:** ${Math.round(score * 100)}%`);
if (node.signature) lines.push(`**Signature:** ${node.signature}`);
lines.push('');
}
return lines.join('\n');
}
private formatNodeList(nodes: Node[], title: string): string {
const lines: string[] = [`## ${title} (${nodes.length} found)`, ''];
for (const node of nodes) {
const location = node.startLine ? `:${node.startLine}` : '';
lines.push(`- **${node.name}** (${node.kind}) - ${node.filePath}${location}`);
}
return lines.join('\n');
}
private formatImpact(symbol: string, impact: Subgraph): string {
const nodeCount = impact.nodes.size;
const edgeCount = impact.edges.length;
const lines: string[] = [
`## Impact Analysis for "${symbol}"`,
'',
`**Nodes affected:** ${nodeCount}`,
`**Relationships:** ${edgeCount}`,
'',
'### Affected Symbols:',
'',
];
// Group by file
const byFile = new Map<string, Node[]>();
for (const node of impact.nodes.values()) {
const existing = byFile.get(node.filePath) || [];
existing.push(node);
byFile.set(node.filePath, existing);
}
for (const [file, nodes] of byFile) {
lines.push(`**${file}:**`);
for (const node of nodes) {
const location = node.startLine ? `:${node.startLine}` : '';
lines.push(` - ${node.name} (${node.kind})${location}`);
}
lines.push('');
}
return lines.join('\n');
}
private formatNodeDetails(node: Node, code: string | null): string {
const location = node.startLine ? `:${node.startLine}` : '';
const lines: string[] = [
`## ${node.name} (${node.kind})`,
'',
`**Location:** ${node.filePath}${location}`,
`**Language:** ${node.language}`,
];
if (node.signature) {
lines.push(`**Signature:** ${node.signature}`);
}
if (node.docstring) {
lines.push('', '### Documentation:', '', node.docstring);
}
if (code) {
lines.push('', '### Code:', '', '```' + node.language, code, '```');
}
return lines.join('\n');
}
private formatTaskContext(context: TaskContext): string {
return context.summary || 'No context found';
}
private textResult(text: string): ToolResult {
return {
content: [{ type: 'text', text }],
};
}
private errorResult(message: string): ToolResult {
return {
content: [{ type: 'text', text: `Error: ${message}` }],
isError: true,
};
}
}
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/**
* MCP Stdio Transport
*
* Handles JSON-RPC 2.0 communication over stdin/stdout for MCP protocol.
*/
import * as readline from 'readline';
/**
* JSON-RPC 2.0 Request
*/
export interface JsonRpcRequest {
jsonrpc: '2.0';
id: string | number;
method: string;
params?: unknown;
}
/**
* JSON-RPC 2.0 Response
*/
export interface JsonRpcResponse {
jsonrpc: '2.0';
id: string | number | null;
result?: unknown;
error?: JsonRpcError;
}
/**
* JSON-RPC 2.0 Error
*/
export interface JsonRpcError {
code: number;
message: string;
data?: unknown;
}
/**
* JSON-RPC 2.0 Notification (no id, no response expected)
*/
export interface JsonRpcNotification {
jsonrpc: '2.0';
method: string;
params?: unknown;
}
// Standard JSON-RPC error codes
export const ErrorCodes = {
ParseError: -32700,
InvalidRequest: -32600,
MethodNotFound: -32601,
InvalidParams: -32602,
InternalError: -32603,
} as const;
export type MessageHandler = (message: JsonRpcRequest | JsonRpcNotification) => Promise<void>;
/**
* Stdio Transport for MCP
*
* Reads JSON-RPC messages from stdin and writes responses to stdout.
*/
export class StdioTransport {
private rl: readline.Interface | null = null;
private messageHandler: MessageHandler | null = null;
/**
* Start listening for messages on stdin
*/
start(handler: MessageHandler): void {
this.messageHandler = handler;
this.rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
terminal: false,
});
this.rl.on('line', async (line) => {
await this.handleLine(line);
});
this.rl.on('close', () => {
process.exit(0);
});
}
/**
* Stop listening
*/
stop(): void {
if (this.rl) {
this.rl.close();
this.rl = null;
}
}
/**
* Send a response
*/
send(response: JsonRpcResponse): void {
const json = JSON.stringify(response);
process.stdout.write(json + '\n');
}
/**
* Send a notification (no id)
*/
notify(method: string, params?: unknown): void {
const notification: JsonRpcNotification = {
jsonrpc: '2.0',
method,
params,
};
process.stdout.write(JSON.stringify(notification) + '\n');
}
/**
* Send a success response
*/
sendResult(id: string | number, result: unknown): void {
this.send({
jsonrpc: '2.0',
id,
result,
});
}
/**
* Send an error response
*/
sendError(id: string | number | null, code: number, message: string, data?: unknown): void {
this.send({
jsonrpc: '2.0',
id,
error: { code, message, data },
});
}
/**
* Handle an incoming line of JSON
*/
private async handleLine(line: string): Promise<void> {
const trimmed = line.trim();
if (!trimmed) return;
let parsed: unknown;
try {
parsed = JSON.parse(trimmed);
} catch {
this.sendError(null, ErrorCodes.ParseError, 'Parse error: invalid JSON');
return;
}
// Validate basic JSON-RPC structure
if (!this.isValidMessage(parsed)) {
this.sendError(null, ErrorCodes.InvalidRequest, 'Invalid Request: not a valid JSON-RPC 2.0 message');
return;
}
if (this.messageHandler) {
try {
await this.messageHandler(parsed as JsonRpcRequest | JsonRpcNotification);
} catch (err) {
const message = parsed as JsonRpcRequest;
if ('id' in message) {
this.sendError(
message.id,
ErrorCodes.InternalError,
`Internal error: ${err instanceof Error ? err.message : String(err)}`
);
}
}
}
}
/**
* Check if message is a valid JSON-RPC 2.0 message
*/
private isValidMessage(msg: unknown): boolean {
if (typeof msg !== 'object' || msg === null) return false;
const obj = msg as Record<string, unknown>;
if (obj.jsonrpc !== '2.0') return false;
if (typeof obj.method !== 'string') return false;
return true;
}
}