ephemeris_progressed_chart

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

The description discloses returned data (planet positions, house cusps, aspects, retrograde status) and credit costs beyond the readOnlyHint annotation. It also mentions extra credit for visual rendering. No contradictions with annotations.

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 three sentences plus a code block; it includes useful but slightly verbose elements. The essential information is present, but some redundancy exists (e.g., repeating ISO 8601 format). Could be more succinct.

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 outlines general return content but lacks details on output structure or pagination. Given no output schema, more specific information about response format (e.g., JSON structure) would improve completeness.

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 already provides 100% parameter descriptions. The description adds an example and notes on credit cost for the 'include_visual' parameter, but does not significantly enhance parameter meaning beyond what the schema offers.

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 states the tool calculates a progressed chart (Secondary Progressed, Solar Arc, or Tertiary) and explicitly details the symbolic advancement method. It distinguishes itself from sibling ephemeris tools like transits or solar returns by focusing on progression methods.

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 an example usage and enumerates methods, but does not explicitly guide when to use this tool versus alternatives like ephemeris_natal_transits or ephemeris_solar_return. The context of when-not-to-use or prerequisite conditions is absent.

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