AI agents call count_substring 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 search in |
substring | string | Yes | Substring to count |
overlapping | boolean | — | Count overlapping occurrences |
case_sensitive | boolean | — | Case sensitive counting |
Parameters from the server's own tool schema.
This is a pure data analysis function that examines an existing string and returns a count. It performs no write operations, does not execute arbitrary code, does not delete data, and has no financial implications. The blast radius of misuse is minimal—a malicious agent could only retrieve statistical information about strings, not modify or destroy data.
From the tool's definition The tool 'count_substring' retrieves or queries data by counting occurrences of a substring within a larger string. No modification, deletion, execution, or financial operations occur.
Attacks that exploit this kind of access
Count occurrences of a substring. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
count_substring accepts 4 parameters: text, substring, overlapping, case_sensitive. Required: text, substring. 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 count_substring: 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.
count_substring 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 count_substring 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 count_substring. 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.
count_substring 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.
count_substring 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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