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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered without the description. The description adds output-shape context (what the 24 hours contain, sunrise/sunset, day ruler) and cost tier, but says nothing about timezone sensitivity, ayanamsa dependence, or rate limits.

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?

Very short and front-loaded, with the output content stated first and cost tacked on as a tag. No wasted sentences, though the brevity is partly under-specification rather than tightness.

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 fields need not be explained, and the description does convey the high-level output. But for a 15-parameter, location- and timezone-sensitive tool with a documented sibling overlap, it omits all input and selection guidance, leaving the agent to infer almost everything from the schema.

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% across 15 parameters, so the description is expected to compensate and does not. It never mentions the required date/time/latitude/longitude inputs, nor that timezone/timezoneOffset and ayanamsa materially change the hora boundaries, which is exactly the ambiguity this tool carries.

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 resource and output: 24 planetary hours (hora) assigned by Chaldean order plus sunrise/sunset and day ruler. That is concrete enough to distinguish from generic list tools, but it never names or differentiates from close siblings like astroway_calendar_planetary_hours or astroway_horary_planetary_hours, which produce overlapping concepts.

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 guidance at all. It does not say when a Vedic hora table is preferable to the calendar or horary planetary-hour tools, nor any prerequisites. The only contextual hints are the [Group: Vedic] and [Cost] tags, which are metadata rather than usage direction.

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