Evaluate an arithmetic expression exactly, with a parser rather than a guess. Numbers, + - * / % ^, parentheses, and a fixed set of functions. Anything else is a parse error; nothing here executes code.
| Name | Required | Description | Default |
|---|---|---|---|
| expression | Yes | e.g. "(1+2)^3 / 7" |
Changes observed during successful MCP inspections. Dates show when Glama detected each change.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full responsibility for behavior. It discloses that evaluation uses a parser (not estimation), that invalid input causes a parse error, and that no code execution occurs—covering safety and error behavior comprehensively.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two sentences, front-loading the primary purpose, then detailing supported syntax, error handling, and safety. Every sentence adds value with no redundancy, making it both concise and well-structured.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple arithmetic tool, the description covers the essential aspects: input format, error behavior, and non-execution. It does not explicitly state the return format or type (e.g., number, string), which is a minor gap, but overall it is reasonably complete given the tool's simplicity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema only defines 'expression' as a string, but the description enriches this by explaining what constitutes a valid expression (numbers, operators, parentheses, functions) and the consequence of invalid input. While the set of functions is not enumerated, the description adds sufficient meaning beyond the basic schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: 'Evaluate an arithmetic expression exactly,' with a specific verb and resource. It further specifies the supported operators and functions, leaving no ambiguity about what the tool does.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for arithmetic evaluation and explicitly states that anything else results in a parse error, providing clear boundaries. However, it does not mention alternatives (e.g., other tools) or when to choose this over them, though the context of the sibling tools may make this implicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.