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

No annotations are supplied, so the description carries the full burden. It implies a pure, side-effect-free calculation, and it does add genuine behavioral context by disclosing the paid-access model ('5 free trial calls per signed wallet'). However, it never states determinism, input tolerance, or the unit of the returned value.

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 front-loaded sentence delivering the verb, resource, and formula, followed by a short promo line. The formula earns its place; the emoji/free-trial blurb is peripheral but does convey cost.

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-input math utility with no annotations and no output schema, the description is close to sufficient, but it omits the unit/period of the result and the output shape, and leaves the input format unaddressed. Minimum viable rather than complete.

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?

With one parameter and 0% schema coverage, the description has to compensate, and it does: 'rate/100' resolves the key ambiguity of whether rate is a decimal or a percent. It does not specify the accepted string format or explain why a compute input is optional (0 required params), which keeps it short of a 5.

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 ('Computes doubling time') and pins it down with the exact formula ln(2)/ln(1+rate/100), which meaningfully separates it from near-neighbors like rule-of72, rule-of69, and half-life even though those siblings are never named. The name/title alone would be ambiguous, but the formula makes the purpose unambiguous.

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 only implied: 'for a percentage rate' hints at the input convention, but there is no statement of when to pick this over rule-of72/rule-of69 approximations, and no exclusions or prerequisites. Adequate for a trivial math utility, but nothing routes the agent away from siblings.

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