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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds two genuinely useful behavioral facts — results are returned step by step, and trig honors a degrees/radians mode — but says nothing about error handling for malformed expressions or the 500-char input limit's consequences.

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?

Front-loaded with a concrete example and the capability list in two tight sentences. The trailing website URL is promotional padding that serves no invocation purpose, but the rest earns its place.

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?

There is no output schema, so the description carries the return-value burden — and 'get each step back' is an adequate if brief account of the step-by-step result. With a trivial two-parameter schema and full annotation coverage, what remains missing (error behavior, precision/rounding) is minor.

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 both `expr` (with its operator/function syntax) and the `angle` enum are already documented in the schema. The description restates the same example expression and mentions degrees or radians, adding no syntax detail beyond what the schema provides. 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?

States a concrete verb (evaluate/type an expression) plus the resource (scientific expression) and enumerates the covered operation families — powers, roots, trig, logs, factorials, nCr, π — which implicitly separates it from the narrower siblings like exponent_calculator, square_root_calculator and logarithm_calculator. An agent can tell what this does without opening the schema.

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?

Usage is implied by the worked example and the operation list, so an agent can infer this is the general-purpose expression evaluator. However, it never explicitly says when to prefer it over the single-purpose siblings (exponent_calculator, logarithm_calculator, square_root_calculator) or states any exclusions.

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