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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine behavioral context beyond that: the exact degree range being tested, its status as a prohibition, and the 10-credit Tier 1 cost, which matters for budgeting repeated calls.

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 compact sentence delivers the purpose, range and astrological significance, followed by terse metadata lines for group, endpoint, required param and cost. Front-loaded and waste-free, though the ASC mention is a small inaccuracy that costs clarity.

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 carry the safety profile. The gap is input semantics: for a single-parameter tool the description never states what form moonLongitude takes, and it advertises an ASC check the tool cannot perform.

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 coverage is 67%; moonLongitude has no description in the schema, and the description only implies it is the Moon's longitude without specifying the coordinate convention (e.g. 0–360 absolute ecliptic degrees vs. sign-relative). The reference to ASC checks suggests a second input that does not exist, adding confusion rather than clarity.

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 a precisely bounded astronomical condition ('check if ... in the Via Combusta (15° Libra – 15° Scorpio)'), which clearly separates it from siblings like horary_moon_voc or horary_diagnostics. It loses a point because it claims to check 'the Moon or ASC' while no ASC input exists in the schema, leaving the actual scope slightly ambiguous.

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 phrase 'a classical prohibition in horary' implies why and when an agent would consult it, but there is no explicit when-to-use, when-not-to-use, or named alternative among the horary siblings. Usage is inferable rather than stated.

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