expression_evaluator
A execute tool on the Math MCP server.
This record as markdown: /tools/111-test-111-math-mcp-server/expression-evaluator.md
What expression_evaluator does on Math MCP Server
AI agents invoke expression_evaluator to trigger actions in Math MCP Server. 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.
Why expression_evaluator is rated High
An 'expression_evaluator' tool likely executes or interprets mathematical expressions, potentially including arbitrary code depending on implementation. Given the empty description, there is uncertainty, but expression evaluation commonly involves executing parsed input which could be misused (e.g., code injection). The most severe plausible category given the name and context is Execute.
From the tool's definition Tool name 'expression_evaluator' on a math server with sibling tools like 'calculus_engine' and 'mathematical_functions'; description is empty and uninformative.
Attacks that exploit this kind of access
The rule that runs expression_evaluator safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Math MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For expression_evaluator, this is the rule to start with:
expression_evaluator 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 Math MCP Server, apply this rule, and every expression_evaluator call is checked against it from then on.
Questions about expression_evaluator
expression_evaluator is a execute tool on the Math MCP Server MCP server. It is categorised as a Execute tool in the Math MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Math MCP Server MCP server in PolicyLayer and add a rule for expression_evaluator: 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 Math MCP Server. Nothing to install.
expression_evaluator 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 expression_evaluator 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 expression_evaluator. 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.
expression_evaluator is provided by the Math MCP Server MCP server (111-test-111/math-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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