Western Compatibility

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

Annotations already cover readOnly/idempotent/destructive hints, so the bar is lower. The description adds useful context by mentioning the output score range, the workflow, and a link to the full output/error contract, which goes beyond the bare annotations without contradicting them.

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 uses clear sections (WORKFLOW, INPUT CONTRACT, DO NOT CONFUSE WITH) and each sentence serves a purpose. It is a bit verbose with all-caps labels but remains well-structured and easy to scan. No fluff or repetition.

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 complexity (nested objects, two persons, many sibling tools), the description provides enough context to select and invoke the tool correctly. It includes a link to the full output/error contract, clarifying what to expect, and it differentiates from the most similar alternatives. A full inline output schema would make it perfect, but the URL suffices.

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?

The input schema has 100% description coverage for every parameter, including nested objects, enums, and defaults. The description itself adds no extra semantic information about parameters; it merely repeats 'person1, person2 — WesternBirthData' which is already in the schema. Hence baseline 3.

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 clearly that it computes a compatibility score (0–100) between two natal charts, and lists the specific components (element affinity, synastry aspects, sign comparisons). It explicitly distinguishes itself from two sibling tools (synastry and zodiac compatibility) which is crucial for disambiguation.

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?

Provides explicit workflow guidance: optional prior call to western_natal, and a follow-up call to western_synastry when more raw aspect detail is needed. Also explicitly states when NOT to use this tool (for raw aspects or sign-only compatibility) by naming alternatives.

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