droid-mcp-core/io.droidmcp.core/ToolResult

ToolResult

data class ToolResult(val isSuccess: Boolean, val data: Map<String, Any?>?, val errorMessage: String?, val images: List<ToolImage> = emptyList())

The outcome of an McpTool.execute call. Exactly one of data / errorMessage is meaningful, selected by isSuccess. The protocol layer maps a result onto the MCP tools/call response: success becomes content, failure becomes an isError: true payload.

Construct via the success / error factories rather than the primary constructor.

Constructors

ToolResult

constructor(isSuccess: Boolean, data: Map<String, Any?>?, errorMessage: String?, images: List<ToolImage> = emptyList())

Types

Companion

object Companion

Properties

data

val data: Map<String, Any?>?

Result map on success; its keys are part of the tool's wire contract. Null on failure.

errorMessage

val errorMessage: String?

Failure description on error; null on success. See the error overloads for the prose vs. short-form (code: detail) conventions.

images

val images: List<ToolImage>

Images to send to MCP clients as image content blocks. Attach them with withImage; in-process callers still read the base64 from data.

isSuccess

val isSuccess: Boolean

Whether the tool completed its work.

Functions

withImage

fun withImage(dataKey: String, mimeType: String): ToolResult

Marks the base64 string at data[dataKey] as an image of mimeType. Over MCP it is sent as an image content block and dataKey is left out of the JSON text and structuredContent, so the payload travels once and clients render it as a picture. data is unchanged, so in-process callers keep reading data[dataKey]. No-op if the key isn't a string.