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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds the definitional boundary of the arc, but it claims to check 'the Moon or ASC' while the schema exposes only moonLongitude — a materially misleading statement about behavior that the agent must reconcile.

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?

Two tight sentences that front-load the core operation and its numeric range, plus compact group/cost metadata. Nothing is wasted, though the ASC clause adds ambiguity rather than value.

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 no explanation, and annotations cover the safety profile. What remains missing is the meaning/format of the sole required parameter and any resolution of the Moon-vs-ASC discrepancy, which an agent needs in order to call this 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?

The required moonLongitude parameter has no description in the schema at all (bare anyOf number/null), and the description never clarifies its expected format, reference frame, or units. Worse, the description advertises an ASC input that does not exist as a parameter, so it actively confuses rather than compensates for the coverage gap.

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+resource ('Check if the Moon or ASC is in the Via Combusta') and even defines the exact arc (15° Libra – 15° Scorpio), so the agent knows precisely what is tested. It does not, however, differentiate itself from adjacent horary tools like astroway_horary_moon_voc or astroway_calendar_moon_voc, leaving the agent to infer which check applies.

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 context is 'a classical prohibition in horary,' which names the domain but not the trigger condition. There is no guidance on when to invoke this versus astroway_horary_moon_voc, astroway_horary_diagnostics, or the broader astroway_horary_horary tool.

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