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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety and non-determinism profile is covered. The description adds genuinely new context by disclosing a concrete cost of 10 credits, which matters for invocation decisions. It does not describe failure modes (e.g., insufficient credits) or output shape, but an output schema exists so the latter is not required.

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?

Single-sentence core is front-loaded and efficient, and the credit note earns its place. However, the leading 'Fortune Teller: Fortune Teller' repeats the name and title twice before any substantive content, which is pure waste in a one-sentence description.

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 two-parameter, zero-required read-only generator with a full output schema and rich annotations, the description covers purpose, domain list, and cost—enough to call correctly. The remaining gap is the absence of routing guidance among the many divination-themed siblings, which is the one thing an agent still has to guess.

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 both parameters are already documented, establishing a baseline of 3. The description does add the category values (love, career, health, wealth, travel) that the schema omits—its category description is only 'Fortune category' with a single 'general' example—but it says nothing about the optional question parameter or its 500-character limit.

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 and resource: 'uses AI to generate personalized mystical fortunes,' and enumerates the topical domains (love, career, health, wealth, travel). It never distinguishes itself from close siblings like FortuneCookieGenerator, Magic8-Ball, or Horoscope, so an agent cannot tell which fortune-style tool to pick from the description alone.

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?

There is no when-to-use or when-not-to-use guidance, and no reference to any alternative tool. The category list implies the scope of requests it accepts, but nothing tells an agent whether to prefer this over FortuneCookieGenerator or Magic8-Ball, or whether a question is required for personalization.

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