Add pagination support to HTTP request tools

src/main/kotlin/net/portswigger/mcp/tools/McpTool.kt

@@ -10,6 +10,7 @@ import kotlinx.serialization.json.Json
 import kotlinx.serialization.serializer
 import net.portswigger.mcp.schema.asInputSchema
 import kotlin.experimental.ExperimentalTypeInference
+import kotlin.math.ceil
 
 @OptIn(InternalSerializationApi::class)
 inline fun <reified I : Any> Server.mcpTool(
@@ -108,6 +109,48 @@ inline fun <reified I : Paginated> Server.mcpPaginatedTool(
     })
 }
 
+/**
+ * Variant of mcpPaginatedTool for tools that return a single (potentially large) string.
+ *
+ * Here, [offset] is a **byte offset** into the response and [count] is the **maximum number
+ * of bytes** to return in this page. The caller (Claude) should start with offset=0 and keep
+ * calling with offset += count until it receives a page whose length is less than count, or
+ * it receives the "Reached end of response" message.
+ *
+ * A safe default page size is 800 000 bytes, which stays well under the 1 MB MCP tool-result
+ * limit even after JSON encoding overhead.
+ */
+inline fun <reified I : Paginated> Server.mcpPaginatedBytesTool(
+    description: String,
+    crossinline execute: I.() -> String
+) {
+    mcpTool<I>(description, execute = {
+        val full = execute(this)
+        val bytes = full.toByteArray(Charsets.UTF_8)
+        val totalBytes = bytes.size
+
+        if (offset >= totalBytes) {
+            val totalPages = ceil(totalBytes.toDouble() / count).toInt().coerceAtLeast(1)
+            "Reached end of response (total bytes: $totalBytes, total pages at this page size: $totalPages)"
+        } else {
+            val end = (offset + count).coerceAtMost(totalBytes)
+            val chunk = bytes.sliceArray(offset until end).toString(Charsets.UTF_8)
+            val remaining = totalBytes - end
+            val totalPages = ceil(totalBytes.toDouble() / count).toInt()
+            val currentPage = ceil(end.toDouble() / count).toInt()
+
+            buildString {
+                appendLine("=== Page $currentPage of $totalPages | bytes $offset–$end of $totalBytes | ${if (remaining > 0) "$remaining bytes remaining" else "last page"} ===")
+                if (remaining > 0) {
+                    appendLine("Call again with offset=$end to get the next page.")
+                }
+                appendLine()
+                append(chunk)
+            }
+        }
+    })
+}
+
 @OptIn(ExperimentalTypeInference::class)
 @OverloadResolutionByLambdaReturnType
 @JvmName("mcpNamedToolString")
@@ -156,5 +199,4 @@ fun String.toLowerSnakeCase(): String {
 interface Paginated {
     val count: Int
     val offset: Int
-}
-
+}

src/main/kotlin/net/portswigger/mcp/tools/Tools.kt

@@ -44,13 +44,13 @@ private fun truncateIfNeeded(serialized: String): String {
 
 fun Server.registerTools(api: MontoyaApi, config: McpConfig) {
 
-    mcpTool<SendHttp1Request>("Issues an HTTP/1.1 request and returns the response.") {
+    mcpPaginatedBytesTool<SendHttp1Request>("Issues an HTTP/1.1 request and returns the response. Response is paginated") {
         val allowed = runBlocking {
             HttpRequestSecurity.checkHttpRequestPermission(targetHostname, targetPort, config, content, api)
         }
         if (!allowed) {
             api.logging().logToOutput("MCP HTTP request denied: $targetHostname:$targetPort")
-            return@mcpTool "Send HTTP request denied by Burp Suite"
+            return@mcpPaginatedBytesTool "Send HTTP request denied by Burp Suite"
         }
 
         api.logging().logToOutput("MCP HTTP/1.1 request: $targetHostname:$targetPort")
@@ -63,7 +63,7 @@ fun Server.registerTools(api: MontoyaApi, config: McpConfig) {
         response?.toString() ?: "<no response>"
     }
 
-    mcpTool<SendHttp2Request>("Issues an HTTP/2 request and returns the response. Do NOT pass headers to the body parameter.") {
+    mcpPaginatedBytesTool<SendHttp2Request>("Issues an HTTP/2 request and returns the response. Do NOT pass headers to the body parameter. Response is paginated") {
         val http2RequestDisplay = buildString {
             pseudoHeaders.forEach { (key, value) ->
                 val headerName = if (key.startsWith(":")) key else ":$key"
@@ -83,7 +83,7 @@ fun Server.registerTools(api: MontoyaApi, config: McpConfig) {
         }
         if (!allowed) {
             api.logging().logToOutput("MCP HTTP request denied: $targetHostname:$targetPort")
-            return@mcpTool "Send HTTP request denied by Burp Suite"
+            return@mcpPaginatedBytesTool "Send HTTP request denied by Burp Suite"
         }
 
         api.logging().logToOutput("MCP HTTP/2 request: $targetHostname:$targetPort")
@@ -193,8 +193,8 @@ fun Server.registerTools(api: MontoyaApi, config: McpConfig) {
 
         mcpTool<GenerateCollaboratorPayload>(
             "Generates a Burp Collaborator payload URL for out-of-band (OOB) testing. " +
-            "Inject this payload into requests to detect server-side interactions (DNS lookups, HTTP requests, SMTP). " +
-            "Use get_collaborator_interactions with the returned payloadId to check for interactions."
+                    "Inject this payload into requests to detect server-side interactions (DNS lookups, HTTP requests, SMTP). " +
+                    "Use get_collaborator_interactions with the returned payloadId to check for interactions."
         ) {
             api.logging().logToOutput("MCP generating Collaborator payload${customData?.let { " with custom data" } ?: ""}")
 
@@ -210,8 +210,8 @@ fun Server.registerTools(api: MontoyaApi, config: McpConfig) {
 
         mcpTool<GetCollaboratorInteractions>(
             "Polls Burp Collaborator for out-of-band interactions (DNS, HTTP, SMTP). " +
-            "Optionally filter by payloadId from generate_collaborator_payload. " +
-            "Returns interaction details including type, timestamp, client IP, and protocol-specific data."
+                    "Optionally filter by payloadId from generate_collaborator_payload. " +
+                    "Returns interaction details including type, timestamp, client IP, and protocol-specific data."
         ) {
             api.logging().logToOutput("MCP polling Collaborator interactions${payloadId?.let { " for payload: $it" } ?: ""}")
 
@@ -341,8 +341,8 @@ data class SendHttp1Request(
     val content: String,
     override val targetHostname: String,
     override val targetPort: Int,
-    override val usesHttps: Boolean
-) : HttpServiceParams
+    override val usesHttps: Boolean, override val count: Int, override val offset: Int
+) : HttpServiceParams, Paginated
 
 @Serializable
 data class SendHttp2Request(
@@ -351,8 +351,8 @@ data class SendHttp2Request(
     val requestBody: String,
     override val targetHostname: String,
     override val targetPort: Int,
-    override val usesHttps: Boolean
-) : HttpServiceParams
+    override val usesHttps: Boolean, override val count: Int, override val offset: Int
+) : HttpServiceParams, Paginated
 
 @Serializable
 data class CreateRepeaterTab(