import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import {
Actions,
ActionSchema,
PayloadSchemas,
ToolResult,
type ToolInput,
} from "./types.js";
import { Context7Client, ApiError } from "./client/index.js";
function getConfig() {
// API key is optional - Context7 works without it but with lower rate limits
const apiKey = process.env.CONTEXT7_API_KEY;
return { apiKey };
}
function success(data: unknown): ToolResult {
return {
content: [{ type: "text", text: JSON.stringify(data, null, 2) }],
};
}
function error(message: string, code?: string): ToolResult {
return {
content: [{ type: "text", text: JSON.stringify({ error: true, message, code }) }],
isError: true,
};
}
async function dispatch(input: ToolInput): Promise<ToolResult> {
const { action, payload = {} } = input;
try {
const config = getConfig();
const client = new Context7Client(config.apiKey);
// Validate and parse payload for the specific action
const schema = PayloadSchemas[action as keyof typeof PayloadSchemas];
const validatedPayload = schema.parse(payload);
switch (action) {
case Actions.RESOLVE_LIBRARY_ID: {
const p = validatedPayload as { libraryName: string; query?: string };
const result = await client.resolveLibraryId(p.libraryName, p.query);
return success({
matches: result,
message: result.length > 0
? `Found ${result.length} matching ${result.length === 1 ? 'library' : 'libraries'}. Use the 'id' field as context7CompatibleLibraryID for get_library_docs.`
: `No libraries found matching "${p.libraryName}". Try a different search term.`,
});
}
case Actions.GET_LIBRARY_DOCS: {
const p = validatedPayload as {
context7CompatibleLibraryID: string;
topic?: string;
tokens?: number;
};
const result = await client.getLibraryDocs(
p.context7CompatibleLibraryID,
{
topic: p.topic,
tokens: p.tokens,
}
);
return success(result);
}
default:
return error(`Unknown action: ${action}`);
}
} catch (err) {
if (err instanceof ApiError) {
return error(err.message, err.code);
}
return error(err instanceof Error ? err.message : String(err));
}
}
function buildDescription(): string {
const actions = Object.values(Actions).join(", ");
return `Context7 documentation operations. Actions: ${actions}. Use action parameter to select operation, payload for action-specific parameters. Provides up-to-date, version-specific library documentation.`;
}
export function registerTools(server: McpServer): void {
server.tool(
"context7",
buildDescription(),
{
action: ActionSchema.describe("Action to perform"),
payload: z.record(z.unknown()).optional().describe("Action-specific parameters"),
},
async (args) => {
return dispatch(args);
}
);
}
