Secondary progressions + solar arc + progressed Moon report.
Shows how the natal chart evolves from birth to the target date.
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | Birth data for chart calculation. IMPORTANT: month is the NUMERIC month (1=January … 12=December). | |
| target_day | Yes | ||
| target_year | Yes | ||
| target_month | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
There are no annotations, so the description must carry the transparency burden. It discloses the calculation methods and the conceptual behavior (evolution over time), but does not mention output format, whether the report is textual, or any prerequisites. This is adequate but with clear gaps.
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?
Two concise sentences, front-loaded with the key purpose and methodology. Every word earns its place, and the structure is clear and scannable.
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 tool has moderate complexity (nested birth data, four required parameters) and no annotations. The description explains the core purpose but omits guidance on target date formatting, report output, or potential constraints. An output schema exists but the description does not integrate it effectively. Adequate but with notable gaps.
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 25% (only the nested 'data' object has a description), yet the tool description does not explain the target_date parameters beyond the generic phrase 'target date.' It fails to compensate for the low schema coverage, leaving the agent without specific guidance for required fields.
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 specifies a clear verb ('Shows') and identifies the exact resource (natal chart evolution) and method (secondary progressions, solar arc, progressed Moon). This distinguishes it from sibling tools like birth_chart or current_transits, which serve different purposes.
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 implies a clear use case (how the natal chart evolves to a target date) and differentiates it from static chart tools. However, it does not explicitly state when not to use it or compare it to alternatives, so it earns 4 rather than 5.
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.
Each tool targets a distinct astrological function: reference lookups (sign, planet, house, aspect), chart calculations (birth_chart, planetary_positions), transit analysis (current_transits, transit_search), progression, calendar generation, and prompt management. Even similar tools like current_transits and transit_search are clearly differentiated by scope (current vs. period-based).
Naming is largely lowercase_snake_case but inconsistent in verb usage: get_* for reference lookups, while others are noun phrases (birth_chart, planetary_positions) or arbitrary verbs (generate_calendar_events). The pattern is readable but not uniform across the set.
12 tools is well within the ideal range for a domain-specific server. Each tool covers a distinct need without redundancy, and the count feels balanced for an astrology API.
The tool surface covers the core astrological workflow: reference data (signs, planets, houses, aspects), chart generation (birth, positions), transits, progressions, and calendar events. The inclusion of prompt tools also supports interpretation, leaving no obvious dead ends.