Description

The @theia/ai-chat extension provides the concept of a language model chat to Theia. It serves as the basis for @theia/ai-chat-ui to provide the Chat UI.

Tool Context Patterns

When implementing tool handlers, there are two patterns depending on whether your tool requires chat-specific features:

Generic Tools (no chat dependency)

For tools that only need basic context like cancellation support:

import { ToolInvocationContext, ToolProvider, ToolRequest } from '@theia/ai-core';

@injectable()
export class MyGenericTool implements ToolProvider {
    getTool(): ToolRequest {
        return {
            id: 'myTool',
            name: 'myTool',
            description: 'A generic tool',
            parameters: { type: 'object', properties: {} },
            handler: async (args: string, ctx?: ToolInvocationContext) => {
                if (ctx?.cancellationToken?.isCancellationRequested) {
                    return JSON.stringify({ error: 'Operation cancelled' });
                }
                // Tool implementation
                return 'result';
            }
        };
    }
}

Chat-Bound Tools (requires chat session)

For tools that need access to the chat session, request model, or response:

import { assertChatContext, ChatToolContext } from '@theia/ai-chat';
import { ToolInvocationContext, ToolProvider, ToolRequest } from '@theia/ai-core';

@injectable()
export class MyChatTool implements ToolProvider {
    getTool(): ToolRequest {
        return {
            id: 'myChatTool',
            name: 'myChatTool',
            description: 'A chat-bound tool',
            parameters: { type: 'object', properties: {} },
            handler: async (args: string, ctx?: ToolInvocationContext) => {
                assertChatContext(ctx); // Throws if not in chat context
                if (ctx.cancellationToken?.isCancellationRequested) {
                    return JSON.stringify({ error: 'Operation cancelled' });
                }
                // Access chat-specific features
                const sessionId = ctx.request.session.id;
                ctx.request.session.changeSet.addElements(...);
                return 'result';
            }
        };
    }
}

The assertChatContext() function serves as both a runtime validator and TypeScript type guard, ensuring the context is a ChatToolContext with request and response properties.

Additional Information

• API documentation for @theia/ai-chat
• Theia - GitHub
• Theia - Website

License

• Eclipse Public License 2.0
• 一 (Secondary) GNU General Public License, version 2 with the GNU Classpath Exception

Trademark

"Theia" is a trademark of the Eclipse Foundation https://www.eclipse.org/theia