This record as markdown: /tools/io-tinyfn-tinyfn/string-length.md
What string_length does on TinyFn
AI agents call string_length 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 | The text to measure |
Parameters from the server's own tool schema.
Why string_length is rated Low
This is a pure computation tool that reads a string parameter and returns a numeric result (its length). It performs no writes, executions, deletions, or financial operations. The deterministic nature of the tool and its utility as a validation/analysis helper in the TinyFn suite confirms it is a safe read operation with minimal risk even if misused by an AI agent.
From the tool's definition Tool name 'string_length' and description 'Get the length of a string' indicate a query operation that retrieves/computes a property of input data with no side effects or state modifications.
Attacks that exploit this kind of access
The rule that runs string_length 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 string_length, this is the rule to start with:
string_length 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 string_length call is checked against it from then on.
Questions about string_length
Get the length of a string. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
string_length accepts 1 parameter: text. Required: text. 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 string_length: 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.
string_length 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 string_length 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 string_length. 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.
string_length 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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