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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered structurally. The description adds one genuinely useful behavioral constraint — inputs must contain only 0/1 digits — but says nothing about error behavior for invalid digits, divide-by-zero, or how results are formatted as binary.

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, front-loaded with the operations and ending with the input constraint. Nothing is wasted and no reading is required before the key information.

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?

With an output schema present, return values need not be explained, and with 100% parameter coverage the schema carries the input contract. The only real gap is the absence of a route away from similar sibling tools, which keeps it short of a 5.

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 description coverage is 100%, so all three parameters are already documented with types, examples, and the operation list; the schema even supplies examples like "1010" and "add". The description's mention of the five operations and the 0/1 constraint merely restates that, so baseline 3 applies.

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 names specific operations (add, subtract, multiply, divide, modulo) against a specific resource (binary numbers) and states the domain constraint (digits 0/1 only), so the agent knows exactly what computation it performs. It doesn't explicitly distinguish itself from close siblings like calculator_binary_decimal (conversion) or calculator_modulo (decimal modulo).

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?

Use is implied by the operation list and the 0/1 constraint, but there is no statement of when to prefer this over calculator_basic, calculator_modulo, or calculator_binary_decimal, and no mention of prerequisites such as operand length limits or matching widths.

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