AI agents call text_format to retrieve information from Onion without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool formats text (JSON, YAML, whitespace removal) and returns a transformed result. It does not persist data, execute code, or interact with external systems. It is a pure text transformation operation, most closely aligned with Read (query/process with no side effects), though it could be considered Write if output is stored.
From the tool's definition 格式化文本内容，支持 JSON、YAML（需 pyyaml）、去除多余空白 — formatting/transforming text without any storage or external side effects
Attacks that exploit this kind of access
格式化文本内容，支持 JSON、YAML（需 pyyaml）、去除多余空白。. It is categorised as a Read tool in the Onion MCP Server, which means it retrieves data without modifying state.
Register the Onion MCP server in PolicyLayer and add a rule for text_format: 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 Onion. Nothing to install.
text_format 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 text_format 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 text_format. 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.
text_format is provided by the Onion MCP server (onion-ai/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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