This record as markdown: /tools/io-tinyfn-tinyfn/null.md
What null does on TinyFn
AI agents call null as a supporting operation in TinyFn workflows.
Why null is rated Low
This tool simply returns a null value with no side effects, no data retrieval, no execution, and no modification. It is a pure deterministic utility that produces a constant output, fitting 'Other' as it does not meaningfully belong to any other category.
From the tool's definition Returns null. For when you need a null.
Attacks that exploit this kind of access
The rule that runs null 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 null, this is the rule to start with:
null gets a rate cap, and 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 null call is checked against it from then on.
Questions about null
Returns null. For when you need a null. It is categorised as a Other tool in the TinyFn MCP Server, which means it performs auxiliary operations.
Register the TinyFn MCP server in PolicyLayer and add a rule for null: 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.
null is a Other tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the null 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 null. 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.
null 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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