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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It does not state whether this is a read-only calculation or if it has side effects (it likely is read-only, but the agent can't be sure). It also doesn't mention any limitations or assumptions (e.g., valid date ranges, accuracy). It adds some value by noting it's 'adapted for Western audiences' and returns an 'English' reading, but it falls short of fully disclosing behavior.

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?

The description is concise, at about two sentences, and front-loads the core purpose. It includes the trigger phrases, which is useful for routing. It is not overly verbose, but it could be slightly more structured (e.g., separating the 'use when' clause), but overall it is efficient and free of fluff.

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 tool with no output schema and no annotations, the description does a decent job of explaining the return value (an English destiny reading). However, it does not provide details on the format of the reading (e.g., length, structure), nor does it mention any edge cases (e.g., invalid dates). It is complete enough to allow an agent to call the tool, but not rich enough to set expectations about the output.

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?

Although the schema already provides full descriptions for all 5 parameters (100% coverage), the description adds valuable context: it explains that gender affects the reading and that the method uses birth date and time. This goes beyond the schema's simple type descriptions by highlighting the significance of gender in determining the outcome. However, it doesn't add details on how each parameter influences the calculation, but that is not required given the schema 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?

The description clearly identifies the tool's purpose: calculating 'destiny weight' from birth data and providing an English reading. It names the specific method (Yuan Tiangang) and distinguishes it from generic fortune-telling, making it unambiguous. It also provides explicit trigger phrases, further clarifying when to use it.

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 includes specific usage triggers ('when the user asks about...'), which is strong guidance. However, it does not mention any alternative tools or when NOT to use it, but since there are no sibling tools listed, this is not a major gap. The explicit 'use when' condition is a clear guideline.

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