Stream Lunar Phase

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

Structurally this tool already declares openWorldHint=true, readOnlyHint=false and idempotentHint=false, yet the description explains none of them — notably why a 'current phase' read is flagged non-read-only. It does add real value with the cost disclosure (10 credits, Tier 1) and the endpoint path, but says nothing about stream connection semantics, whether frames repeat, or latency.

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 content sentence up front, followed by three bracketed metadata lines that each carry distinct information (group, endpoint, price). Nothing is padded or repeated.

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 and annotations already cover the return shape and safety profile, so the description does not need to restate them. What is missing is the distinction from the moon-phase calendar and render siblings and any hint about how the streaming behaviour manifests — the two things an agent actually cannot infer from structured fields.

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 tool takes zero parameters and the schema is empty, so there is nothing for the description to disambiguate; baseline 4 applies. A note on whether the phase is computed for 'now' in a default timezone would help, but the absence of parameters means low risk of mis-invocation.

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 states the payload contents precisely ('current 8-phase + countdown to next major phase'), so an agent knows roughly what comes back. But there is no explicit verb and no differentiation from close siblings such as astroway_calendar_moon_phase, astroway_render_moon_phase, or astroway_psychological_modern_rudhyar_lunation_phase, all of which concern lunar phase; the 'stream' framing in the name is never explained in the text.

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?

No indication of when to call this instead of the calendar or render lunar-phase siblings, no mention of polling/repeat use for a streaming endpoint, and no exclusions. The agent must guess the selection rule from the name alone.

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