import { McpSessionContext } from '../../context';
import {
Tool,
ToolInput,
ToolInputSchema,
ToolOutput,
ToolOutputSchema,
} from '../types';
import { z } from 'zod';
const DEFAULT_MAX_TEXT_LENGTH = 50_000;
export interface GetAsTextInput extends ToolInput {
selector?: string;
maxLength: number;
}
export interface GetAsTextOutput extends ToolOutput {
output: string;
}
export class GetAsText implements Tool {
name(): string {
return 'content_get-as-text';
}
description(): string {
return 'Gets the visible text content of the current page.';
}
inputSchema(): ToolInputSchema {
return {
selector: z
.string()
.describe(
'CSS selector to limit the text content to a specific container.'
)
.optional(),
maxLength: z
.number()
.int()
.positive()
.describe(
`Maximum number of characters to return (default: "${DEFAULT_MAX_TEXT_LENGTH}").`
)
.optional()
.default(DEFAULT_MAX_TEXT_LENGTH),
};
}
outputSchema(): ToolOutputSchema {
return {
output: z
.string()
.describe('The requested text content of the page.'),
};
}
async handle(
context: McpSessionContext,
args: GetAsTextInput
): Promise<GetAsTextOutput> {
const { selector, maxLength } = args;
const visibleText: string = await context.page.evaluate(
({ selector }): string => {
const root: Element | null = selector
? document.querySelector(selector)
: document.body;
if (!root) {
throw new Error(
`Element with selector "${selector}" not found`
);
}
const walker: TreeWalker = document.createTreeWalker(
root,
NodeFilter.SHOW_TEXT,
{
acceptNode: (node: Node) => {
const style: CSSStyleDeclaration =
window.getComputedStyle(node.parentElement!);
return style.display !== 'none' &&
style.visibility !== 'hidden'
? NodeFilter.FILTER_ACCEPT
: NodeFilter.FILTER_REJECT;
},
}
);
let text: string = '';
let node;
while ((node = walker.nextNode())) {
const trimmedText: string | undefined =
node.textContent?.trim();
if (trimmedText) {
text += trimmedText + '\n';
}
}
return text.trim();
},
{ selector }
);
// Truncate logic
let output: string = visibleText;
if (output.length > maxLength) {
output =
output.slice(0, maxLength) +
'\n[Output truncated due to size limits]';
}
return {
output,
};
}
}
