This record as markdown: /tools/io-tinyfn-tinyfn/add-query-param.md
What add_query_param does on TinyFn
AI agents use add_query_param to create or update resources in TinyFn, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your TinyFn environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
key | string | Yes | Parameter key |
url | string | Yes | URL to modify |
value | string | Yes | Parameter value |
Parameters from the server's own tool schema.
Why add_query_param is rated Medium
This tool creates or modifies a URL by appending query parameters. This is a reversible write operation—the original URL can be reconstructed or the parameter removed. It does not execute code, delete data, or trigger external operations. The impact is limited to string manipulation with no side effects on external systems.
From the tool's definition Tool description: 'Add a query parameter to a URL.' The verb 'Add' indicates modification of data (the URL string) in a reversible manner.
Risk signalsAccepts URL/endpoint input (url)
Attacks that exploit this kind of access
The rule that runs add_query_param 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 add_query_param, this is the rule to start with:
add_query_param stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. 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 add_query_param call is checked against it from then on.
Questions about add_query_param
Add a query parameter to a URL. It is categorised as a Write tool in the TinyFn MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
add_query_param accepts 3 parameters: key, url, value. Required: key, url, value. 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 add_query_param: 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.
add_query_param is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the add_query_param 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 add_query_param. 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.
add_query_param 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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