mcp-playwright

Instructions

Implementation Reference

• src/tools/api/requests.ts:34-72 (handler)

  PostRequestTool class with execute method implementing the HTTP POST request logic using Playwright's request context, handling JSON parsing, headers including auth token, and response formatting.

  export class PostRequestTool extends ApiToolBase {
    /**
     * Execute the POST request tool
     */
    async execute(args: any, context: ToolContext): Promise<ToolResponse> {
      return this.safeExecute(context, async (apiContext) => {
        // Check if the value is valid JSON if it starts with { or [
        if (args.value && typeof args.value === "string" && (args.value.startsWith("{") || args.value.startsWith("["))) {
          try {
            JSON.parse(args.value);
          } catch (error) {
            return createErrorResponse(`Failed to parse request body: ${(error as Error).message}`);
          }
        }
  
        const response = await apiContext.post(args.url, {
          data: typeof args.value === "string" ? JSON.parse(args.value) : args.value,
          headers: {
            "Content-Type": "application/json",
            ...(args.token ? { Authorization: `Bearer ${args.token}` } : {}),
            ...(args.headers || {}),
          },
        });
  
        let responseText: string;
        try {
          responseText = await response.text();
        } catch (_error) {
          responseText = "Unable to get response text";
        }
  
        return createSuccessResponse([
          `POST request to ${args.url}`,
          `Status: ${response.status()} ${response.statusText()}`,
          `Response: ${responseText.substring(0, 1000)}${responseText.length > 1000 ? "..." : ""}`,
        ]);
      });
    }
  }

• src/tools.ts:285-301 (schema)

  Input schema definition for the playwright_post tool, defining required url and value, optional token and headers.

    name: "playwright_post",
    description: "Perform an HTTP POST request",
    inputSchema: {
      type: "object",
      properties: {
        url: { type: "string", description: "URL to perform POST operation" },
        value: { type: "string", description: "Data to post in the body" },
        token: { type: "string", description: "Bearer token for authorization" },
        headers: {
          type: "object",
          description: "Additional headers to include in the request",
          additionalProperties: { type: "string" },
        },
      },
      required: ["url", "value"],
    },
  },

• src/toolHandler.ts:628-629 (registration)

  Dispatch in handleToolCall switch statement that calls the postRequestTool handler for 'playwright_post'.

  case "playwright_post":
    return await postRequestTool.execute(args, context);

• src/toolHandler.ts:408-408 (registration)

  Instantiation of PostRequestTool instance in initializeTools function.

  if (!postRequestTool) postRequestTool = new PostRequestTool(server);

• src/tools/api/requests.ts:7-29 (helper)

  Example of ApiToolBase extension (GetRequestTool), showing the base class provides safeExecute for API tools.

  export class GetRequestTool extends ApiToolBase {
    /**
     * Execute the GET request tool
     */
    async execute(args: any, context: ToolContext): Promise<ToolResponse> {
      return this.safeExecute(context, async (apiContext) => {
        const response = await apiContext.get(args.url);
  
        let responseText: string;
        try {
          responseText = await response.text();
        } catch (_error) {
          responseText = "Unable to get response text";
        }
  
        return createSuccessResponse([
          `GET request to ${args.url}`,
          `Status: ${response.status()} ${response.statusText()}`,
          `Response: ${responseText.substring(0, 1000)}${responseText.length > 1000 ? "..." : ""}`,
        ]);
      });
    }
  }