Calculator

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It discloses the supported operators and gives an example, which is helpful, but it does not state what happens on invalid input, division by zero, or overflow, nor does it describe the return format (number, string, precision). For a simple calculator the behavior is fairly predictable, but these gaps remain.

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?

One sentence plus an illustrative example with zero waste. The purpose is front-loaded in the first few words, and the example reinforces the message efficiently.

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 single-parameter calculator with 100% schema coverage, the definition is mostly complete. It covers scope and usage. Minor gaps—return type and error behavior—are acceptable for such a simple, low-risk tool, though stating the result format would make it fully self-contained.

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?

Schema coverage is 100%, so the schema already documents the single 'expression' parameter. The description adds the supported operator list and an example, which marginally extends the schema's own example, but does not add meaningful new semantics beyond what the schema already conveys. Baseline 3 applies given the high coverage.

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?

States a specific verb ('Evaluate'), the resource ('arithmetic expression'), and the exact scope (+, -, *, /, parentheses, decimals) with a concrete example. The sibling tools (get_weather, get_current_time, add_note, etc.) are all clearly distinct, so there is no ambiguity about what this 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 makes clear it handles 'basic' arithmetic, which implies it is not for advanced math, but there is no explicit when-to-use or when-not-to-use statement. Sibling differentiation is not needed since no sibling overlaps, but the guidance is implied rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.