Moon Phase

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

Annotations already cover read-only, idempotent, non-destructive, closed-world, so the safety profile needs no repetition. The description adds distinct value beyond them: the computational basis (Meeus Ch.48 geocentric Sun-Moon elongation), the endpoint, and the cost (10 credits, Tier 1), which the agent needs for budgeting.

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 output fields come first, followed by the method note and the compact bracketed metadata block. Every element earns its place, though the inline group/endpoint/cost tags slightly fragment the prose.

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 needn't be described, and cost/endpoint/method are covered. But for a 13-parameter tool with thin schema coverage and no when-to-use guidance, the description leaves the agent guessing about the sidereal/house-system options and alternative tools.

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 must carry real weight here, and it does not. It names the four required parameters but that duplicates the schema's required array, and it says nothing about the nine optional parameters (ayanamsa, zodiacType, houseSystem, timezone/timezoneOffset interplay, cosmogram, city/name) that are largely undocumented elsewhere.

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 concrete verb and resource ('moon phase at a given moment') and enumerates the exact outputs (illumination %, age, elongation, waxing/waning, sun/moon signs), so an agent knows what it gets. It does not explicitly differentiate itself from nearby siblings such as astroway_render_moon_phase or astroway_calendar_lunar_calendar, which keeps it below 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?

The only usage-adjacent content is the '[Required: date, time, latitude, longitude]' tag, which restates the schema's required list. There is no statement of when to pick this over astroway_render_moon_phase, astroway_stream_lunar_phase, or astroway_calendar_lunar_calendar, and no exclusions or prerequisites.

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