AI agents call preview_data to retrieve information from Astro MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
preview_data retrieves and displays information about files (metadata, structure, samples) without modifying, executing code, deleting, or moving money. It is fundamentally a read operation. The low severity reflects that viewing file previews poses minimal risk—the worst outcome would be exposure of sensitive data already accessible to the user, not unintended modifications or deletions.
From the tool's definition Tool description states it 'Shows file metadata, structure, and sample data' and 'Provides Python code examples for manual file loading.' These are purely informational operations with no side effects.
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
Shows file metadata, structure, and sample data with full file paths for easy loading. Works with all file types from any data source. Provides Python code examples for manual file loading. It is categorised as a Read tool in the Astro MCP MCP Server, which means it retrieves data without modifying state.
Register the Astro MCP server in PolicyLayer and add a rule for preview_data: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Astro MCP. Nothing to install.
preview_data is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the preview_data rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for preview_data. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
preview_data is provided by the Astro MCP server (sandyyuan/astro_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
preview_data is one line of Astro's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
Teams ship this data inside their own products. See what a licence covers →