Compute a deterministic BaZi (八字) / Korean Saju (사주) Four Pillars chart from a solar birth date: Heavenly Stems, Earthly Branches, Day Master, and five-element distribution. KASI-validated engine, no AI.
| Name | Required | Description | Default |
|---|---|---|---|
| day | Yes | ||
| hour | No | 0–23, or -1 if birth time unknown | |
| year | Yes | 1920–2050 | |
| month | Yes | ||
| gender | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so description carries full burden. It states the tool is 'deterministic' and 'KASI-validated', giving some insight into computation reliability. However, it does not disclose potential error conditions, authentication needs, or side effects. For a compute-only tool, this is adequate but not comprehensive.
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 a single concise sentence that immediately states the purpose and outputs. It is front-loaded with the key action. No unnecessary words, making it efficient for an agent to parse.
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?
Given the tool has no output schema, the description adequately lists the chart components (Stems, Branches, Day Master, distribution). It covers what the agent needs to know about the result. Missing error handling or edge cases, but for a compute tool this is reasonably 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?
Schema coverage is only 40%, meaning most parameters (day, month, gender) lack description. The tool description does not add meaning beyond listing the chart components. It does not explain how parameters like 'gender' or 'hour' influence the output, leaving ambiguity for the agent.
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?
Description clearly states the tool computes a deterministic BaZi/Saju chart from solar birth date, listing outputs (Heavenly Stems, Earthly Branches, Day Master, five-element distribution). The name and description distinguish it from the sibling tool 'bazi_compatibility' by focusing on single chart computation.
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 mentions 'KASI-validated engine, no AI' implying reliability but does not explicitly state when to use this tool versus the sibling 'bazi_compatibility'. There is no guidance on prerequisites or when not to use. The context of a single sibling suggests the alternative is for compatibility, but it's not stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
The two tools have clearly distinct purposes: one computes an individual's BaZi chart, the other calculates compatibility between two people. No overlap or ambiguity.
Both tools follow a consistent 'bazi_' prefix with snake_case and descriptive nouns ('chart' and 'compatibility'), forming a predictable pattern.
With only 2 tools, the server is narrowly scoped but still provides the core BaZi functionalities. The count is slightly below the typical 3-15 range but suits the focused purpose.
The server covers the essential BaZi operations: chart generation and compatibility calculation. Minor gaps exist (e.g., no detailed interpretation or advance forecasting), but the basic use cases are well-covered.