Western Solar Arc

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

The annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint, so the safety profile is fully covered. The description adds meaningful behavioral context by explaining the calculation rule and the uniform rate of progression, which helps callers understand what the tool does without needing to infer it from the name alone.

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) with no redundant or filler language. Every sentence contributes either the calculation method, the prerequisite, the input default, or a disambiguation from sibling tools.

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?

The description is complete for the tool's complexity: it states the prerequisite chart, the optional target date, the disambiguation from similar tools, and points to a full output/error contract URL. Since an output schema is present, describing return values inline is not necessary, and the provided link covers any additional output details.

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 covers 100% of the parameters with detailed descriptions, including nested birth fields, enums, defaults, and formats, so the baseline is met. The description's INPUT CONTRACT adds little beyond restating target_date's default and naming 'WesternBirthData', which does not materially enhance the schema's already thorough semantics.

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 as computing Solar Arc Directions for a target date and explains the method (progressed Sun minus natal Sun, uniformly applied). It explicitly distinguishes itself from secondary progressions and daily transits among sibling tools, leaving no ambiguity about its unique purpose.

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 provides a concrete workflow prerequisite by stating BEFORE: asterwise_get_western_natal and notes AFTER: None. It also gives explicit when-not-to-use guidance by contrasting with secondary progressions and daily transits, and documents the target_date default so callers know when it can be omitted.

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