Evaluate an arithmetic expression with + - * / // % and parentheses. No functions, no names.
AI agents call do_math to retrieve information from Nexus Core without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
do_math performs a pure computational read: it takes a mathematical expression as input and returns its evaluated result. No state is changed, no files are created or deleted, no external systems are called. This is a deterministic information retrieval operation with zero side effects, fitting squarely in the Read category.
From the tool's definition Tool evaluates arithmetic expressions with basic operators (+, -, *, /, //, %, **) and parentheses only. No data modification, no code execution, no external side effects. Description explicitly states 'No functions, no names.'
Attacks that exploit this kind of access
Evaluate an arithmetic expression with + - * / // % and parentheses. No functions, no names. It is categorised as a Read tool in the Nexus Core MCP Server, which means it retrieves data without modifying state.
Register the Nexus Core MCP server in PolicyLayer and add a rule for do_math: 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 Nexus Core. Nothing to install.
do_math 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 do_math 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 do_math. 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.
do_math is provided by the Nexus Core MCP server (noumenon-ai/nexus-core). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
do_math is one line of Nexus Core'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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