fix(library): link the marketing platform vs agent builder guide

Author: waleedlatif1

apps/sim/content/library/best-marketing-automation-platforms-ai-workflows-2026/index.mdx

@@ -117,6 +117,8 @@ AI workflow builders commonly center on capabilities such as:
 
 A traditional suite is usually the better primary purchase when marketing needs one place to manage contacts and campaigns. An AI workflow builder is usually the better primary purchase when the main requirement is to coordinate models and tools around existing systems. Our [marketing automation agent guide](https://www.sim.ai/library/ai-agents-for-marketing-automation) explores practical applications in more detail.
 
+To decide which category your team needs before comparing vendors, read [Marketing Automation Platform vs AI Agent Builder](https://www.sim.ai/library/marketing-automation-platform-vs-ai-agent-builder).
+
 ## How were the best marketing automation platforms scored?
 
 This Sim comparison scores each platform from 1 to 5 on six buyer criteria, with 5 indicating the strongest fit for that criterion rather than the best product overall.