This record as markdown: /tools/io-github-kivanccakmak-yaver/calculate.md
What calculate does on Yaver
AI agents invoke calculate to trigger actions in Yaver. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
| Parameter | Type | Required | Description |
|---|---|---|---|
expression | string | Yes | Math expression (e.g. '2^10', 'sqrt(144)', '3.14 * 5^2') |
Parameters from the server's own tool schema.
Why calculate is rated High
Evaluating a math expression involves executing computation logic. While this is generally low-risk (no file system, network, or data access implied), it falls under Execute because it runs code/expressions dynamically. Blast radius is low assuming it is sandboxed to pure math evaluation with no side effects.
From the tool's definition "Evaluate a math expression" — the tool actively evaluates/executes an expression rather than simply reading static data.
Risk signalsAccepts freeform code/query input (expression)
Attacks that exploit this kind of access
The rule that runs calculate safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Yaver, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For calculate, this is the rule to start with:
calculate stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Yaver, apply this rule, and every calculate call is checked against it from then on.
Questions about calculate
Evaluate a math expression. It is categorised as a Execute tool in the Yaver MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
calculate accepts 1 parameter: expression. Required: expression. The full parameter table on this page comes from the server's own tool schema.
Register the Yaver MCP server in PolicyLayer and add a rule for calculate: 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 Yaver. Nothing to install.
calculate is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the calculate 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 calculate. 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.
calculate is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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