Function mcpResultToExecutableOutput

packages/agent-core/src/mcp/output.ts:150–192

(
  result: MCPToolResult,
  qualifiedToolName: string,
  options: McpOutputOptions = {},
)

 * wrap when the result is media-only, so the model can attribute binary parts.
 */
export async function mcpResultToExecutableOutput(
  result: MCPToolResult,
  qualifiedToolName: string,
  options: McpOutputOptions = {},
): Promise<{ output: string | ContentPart[]; isError: boolean; truncated?: true }> {
  const converted: ContentPart[] = [];
  for (const block of result.content) {
    const part = convertMCPContentBlock(block);
    if (part !== null) {
      converted.push(part);
    }
  }

  const wrapped = wrapMediaOnly(converted, qualifiedToolName);
  // Text budget FIRST, on the tool's own text only: captions inserted by the
  // compression step below must never compete with a chatty tool's text for
  // the budget — an evicted or mid-string-sliced caption silently
  // reintroduces the downsampling this pipeline promises to announce.
  const budgeted = applyTextBudget(wrapped);
  // Shrink oversized images BEFORE the per-part byte cap, so a large but
  // compressible screenshot is downsampled and kept rather than dropped to a
  // text notice. Compression is never silent: each re-encoded image gains a
  // caption stating what the original was, and the original bytes are
  // persisted (best effort, into the session's media-originals dir when
  // known) so the model can read detail back via ReadMediaFile + region.
  // Parts that cannot be compressed pass through.
  const compressed = await compressImageContentParts(budgeted.parts, {
    annotate: {
      persistOriginal: (bytes, mimeType) =>
        persistOriginalImage(
          bytes,
          mimeType,
          options.originalsDir === undefined ? {} : { dir: options.originalsDir },
        ),
    },
  });
  const capped = applyBinaryPartCap(compressed);
  const truncated = budgeted.truncated || capped.truncated;
  const output = collapseSingleText(capped.parts);
  return truncated
    ? { output, isError: result.isError, truncated: true }
    : { output, isError: result.isError };
}

/**
 * If `parts` contains media but no non-empty text, surround it with