Mastra vs Vertex AI Agent Builder

as AI assistants see them, week of 2026-10-19

brag about it: X · LinkedIn

Mastra and Vertex AI Agent Builder both sit near the bottom of the pack, with overall scores of 8 and 9 out of 100. Mastra is named in 12 of 71 answers, Vertex AI Agent Builder in 14 of 71. Mastra does best on "Which AI agent framework should a developer choose?" and "What's the best tool for building multi-agent systems?" (2 of 3 answers each), while Vertex AI Agent Builder is named in every answer (4 of 4) for "What are the best platforms for building AI agents?" Head-to-head, they're evenly matched: each wins 4 questions outright, with 12 ties. Neither is ever mentioned for voice agents, non-technical founders, or self-hosted setups.

Head to head

metric	Mastra	Vertex AI Agent Builder
score	11	12
questions won	14	13

By assistant

Mastra

assistant	score	named in, this week	usual spot, this week
ChatGPT	6	10% of answers	#6.0
Claude	21	45% of answers	#7.3
Gemini	not sampled this week
Perplexity	11	22% of answers	#5.3

Vertex AI Agent Builder

assistant	score	named in, this week	usual spot, this week
ChatGPT	14	20% of answers	#5.8
Claude	11	30% of answers	#11.3
Gemini	not sampled this week
Perplexity	13	33% of answers	#5.5

Where they differ

Only Mastra gets named for

What's the best platform to build AI agents that use MCP tools?
What's the best tool to build an AI agent that answers customer emails?
Which AI agent platform has the best pricing for a small team?

Only Vertex AI Agent Builder gets named for

What's the best platform to build and deploy AI agents for a startup?
What's the best tool to automate a business workflow with AI agents?

More comparisons

Not sold on either?

Scores count how often each assistant names a product, weighted by position. How the score works · Full AI agent builders leaderboard