extract_groups
Extract capture groups from a pattern match.
This record as markdown: /tools/io-tinyfn-tinyfn/extract-groups.md
What extract_groups does on TinyFn
AI agents call extract_groups to retrieve information from TinyFn without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
text | string | Yes | Text to search |
pattern | string | Yes | Pattern with capture groups |
Parameters from the server's own tool schema.
Why extract_groups is rated Low
This tool performs string pattern matching and data extraction. It reads and returns captured groups from text without side effects, making it a Read category tool. The severity is low because misuse would only return unexpected string data without affecting system state, data integrity, or external operations.
From the tool's definition Tool description states 'Extract capture groups from a pattern match' - this is a read-only operation that retrieves data from a regex pattern without modifying, deleting, or executing external operations.
Attacks that exploit this kind of access
The rule that runs extract_groups safely
PolicyLayer is an MCP gateway: it sits between your AI agents and TinyFn, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For extract_groups, this is the rule to start with:
extract_groups is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect TinyFn, apply this rule, and every extract_groups call is checked against it from then on.
Questions about extract_groups
Extract capture groups from a pattern match. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
extract_groups accepts 2 parameters: text, pattern. Required: text, pattern. 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 extract_groups: 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.
extract_groups 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 extract_groups 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 extract_groups. 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.
extract_groups 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.
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