AI agents call starts_with to retrieve information from TinyFn without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
text | string | Yes | The text to check |
prefix | string | Yes | The prefix to look for |
Parameters from the server's own tool schema.
This is a deterministic utility function that performs a read-only text validation check. It retrieves no sensitive data, modifies nothing, executes no external operations, and poses minimal risk if misused by an AI agent. The tool is purely informational.
From the tool's definition Tool name 'starts_with' and description 'Check if text starts with a prefix' indicate a simple string comparison operation that queries/validates input data without modification or side effects.
Attacks that exploit this kind of access
Check if text starts with a prefix. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
starts_with accepts 2 parameters: text, prefix. Required: text, prefix. The full parameter table on this page comes from the server's own tool schema.
Register the TinyFn MCP server in PolicyLayer and add a rule for starts_with: 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 TinyFn. Nothing to install.
starts_with 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 starts_with 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 starts_with. 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.
starts_with is provided by the TinyFn MCP server (https://api.tinyfn.io/mcp/all/). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
starts_with is one line of TinyFn's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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