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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed world), and the description adds genuinely useful context beyond them: AI-written (not pre-generated), grounded in current Moon phase/transits, multi-language, and a 50-credit cost. These are behavioral traits an agent benefits from knowing before calling.

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?

Front-loaded with a clear purpose sentence, followed by two brief supporting clauses and cost/group tags. Appropriately sized with no wasted prose, though the bracketed metadata adds minor clutter.

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 explained, and annotations cover safety. However, for a 6-parameter tool with low schema coverage, the description omits parameter-level guidance and any routing versus the horoscope siblings, leaving meaningful gaps.

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% (date, sign, language, disclaimer_inline are undocumented), so the description carries more of the burden. It only alludes to the language parameter via 'Multi-language' and says nothing about date, precision, fields, or disclaimer_inline, leaving the coverage gap unaddressed.

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 ('Generate') and resource ('daily horoscope') scoped by zodiac sign. The 'daily' cadence implicitly contrasts with siblings like weekly/monthly/yearly, but the description never names or explicitly differentiates itself from them.

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 when-to-use, when-not-to-use, or alternatives guidance. It describes what the tool is ('grounded in real ephemeris data', 'AI-written') but never tells the agent when to pick this over astroway_horoscope_weekly, _monthly, or _yearly.

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