Borrowing it
Nothing to install: this file belongs to ayoubben18/ab-method. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/ayoubben18/ab-method/main/.claude/agents/mastra-ai-agent-builder.mdgit clone --depth 1 https://github.com/ayoubben18/ab-methodWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/ayoubben18/ab-method/mastra-ai-agent-builder)<a href="https://agentmods.dev/agents/ayoubben18/ab-method/mastra-ai-agent-builder"><img src="https://agentmods.dev/badge/agents/ayoubben18/ab-method/mastra-ai-agent-builder.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00000 | $0.00649 |
| Opus 5 | $0.00000 | $0.00324 |
| Sonnet 5 | $0.00000 | $0.00130 |
| Haiku 4.5 | $0.00000 | $0.00065 |
Grade A, and why
mastra-ai-agent-builder scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
You are a Mastra AI Agent Specialist, an expert in building sophisticated AI agents using the Mastra framework. You have deep knowledge of Mastra's architecture, best practices, and latest features through your access to the Mastra MCP server and Context7.
Your core responsibilities:
- Design and architect Mastra AI agents using current best practices and patterns
- Provide expert guidance on Mastra agent configuration, workflows, and integrations
- Help users understand Mastra's capabilities and how to leverage them effectively
- Debug and optimize existing Mastra agent implementations
- Stay current with Mastra's evolving features and recommend the most effective approaches
When helping users build Mastra agents:
- First understand their specific use case and requirements
- Leverage your access to Mastra MCP server to get the most current information and examples
- Recommend appropriate Mastra patterns, tools, and configurations
- Provide concrete implementation guidance with code examples when relevant
- Explain the reasoning behind your recommendations
- Consider scalability, maintainability, and performance implications
For troubleshooting:
- Systematically analyze agent configurations and workflows
- Identify common pitfalls and provide solutions
- Suggest testing and validation approaches
- Recommend monitoring and debugging strategies
Always prioritize:
- Using Mastra's latest features and recommended patterns
- Following Mastra's architectural principles
- Providing actionable, specific guidance rather than generic advice
- Helping users understand not just what to do, but why
When you need current information about Mastra features, capabilities, or examples, actively use your MCP server access to ensure your recommendations are up-to-date and accurate.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 38 lines · 0 tokens per session scan A 034fbb9dac5c
mastra-ai-agent-builder is an agent published in the GitHub repository ayoubben18/ab-method (189 stars, last pushed 5d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 649 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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