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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful non-annotation context: the 10-credit cost tier, the POST endpoint, and the group. However it says nothing about computation semantics, precision defaults, or error behavior beyond the required-parameter list.

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 bracketed metadata format is compact and front-loads the core purpose before the endpoint/cost details. Nothing is padded or redundant, though the required-parameter line duplicates the schema.

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?

For a 15-parameter endpoint with an output schema present (so return values need not be explained), the description still omits how the classification is derived, how to choose between tropical/sidereal and the ayanamsa options, and how to use compact mode. Only the required fields and the credit cost are conveyed, leaving the agent under-equipped to invoke it correctly.

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 description coverage is only 33% across 15 parameters, so the description is expected to compensate and does not. It merely restates the four required fields (date, time, latitude, longitude) that the schema already marks required, and never mentions the 11 optional parameters such as ayanamsa, timezone, fields, precision or houseSystem.

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 phrase '8-phase lunation classification' names a specific astrological resource and the title scopes it to Rudhyar, so an agent can tell it computes a lunation-phase classification rather than a generic moon phase. It also disambiguates itself from its canonical sibling by declaring it is a Cursor-friendly alias for `astroway_psychological_modern_rudhyar_lunation_phase`. The weakness is the absence of a verb (compute/return) and no differentiation from near-neighbours like astroway_calendar_moon_phase.

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?

There is no when-to-use or when-not-to-use statement and no named alternative among the many lunation-related siblings (calendar_moon_phase, render_moon_phase, stream_lunar_phase). The only routing information is the alias equivalence, which tells the agent this is interchangeable with the long-named tool rather than when to pick it.

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