Planetary Phases

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely useful operational metadata (POST endpoint, 20 credits / Tier 2 cost) but says nothing about frame of reference (geocentric vs heliocentric), whether the phase is computed for an instant or a range, or how geography affects the result.

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?

One dense sentence followed by a compact bracketed metadata block; the core purpose is front-loaded with no filler. The required-parameter line is redundant with the schema, a small waste, but overall the definition is tight.

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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. However, for a 13-parameter tool at 23% schema coverage, the description leaves the optional astrological configuration parameters (zodiacType, houseSystem, ayanamsa) entirely uncontextualized, which is a meaningful gap for correct invocation.

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 23% across 13 parameters, so the description is expected to compensate — instead it merely repeats the four required fields already declared in the schema's required array. The nine optional parameters (zodiacType, houseSystem, ayanamsa, timezone, cosmogram, city, name, etc.) and whether they alter phase output are never addressed.

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 a specific verb and resource ('Calculate the synodic phase of each planet relative to the Sun') and enumerates the eight phase names, which disambiguates the term 'synodic phase' without needing the schema. It does not explicitly distinguish itself from near-siblings such as astroway_calendar_planetary_cycles or astroway_psychological_modern_rudhyar_lunation_phase, so it falls short of a 5.

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 statement of when to use this tool, when not to, or which sibling to prefer for overlapping cycle/phase questions. The only contextual hints are the '[Group: Calendar & Cycles]' tag and the required-parameter line, neither of which guides selection.

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