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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds useful behavioral context — that each school withholds different gems and orders results differently, and that malefics are surfaced as gems to avoid — but says nothing about response shape, credits consumed (20) or error behavior in the description text itself.

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 front-loaded sentences with no filler: the deliverable comes first, then the school mechanics. Dense Vedic terminology is justified by the domain, though the school sentence is long and could be split for scanability.

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?

With an output schema present and a fully-described input schema, the description need not document returns or parameters. It adequately covers purpose and mode selection; the one real gap is disambiguation from astroway_vedic_gemstones_navaratna and the omission of the coordinate-non-defaulting caveat that the schema carries.

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 100%, so the baseline is 3. The description goes beyond it by explaining what lagna-lord prescribes (1st/9th/5th lords as life/lucky/benefic stones) and what functional-benefic does (classification by owned houses, yogakaraka-led, malefics flagged as avoid), giving an agent a reason to pick a school rather than just an enum label.

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 deliverable — which of the nine gems to wear — and grounds it in the sidereal lagna, then distinguishes two implementation schools by name. It does not, however, distinguish this tool from the sibling astroway_vedic_gemstones_navaratna, which an agent must resolve to choose correctly.

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 description never says when to pick this tool over the navaratna sibling or other Vedic endpoints, nor does it state prerequisites (e.g. that coordinates are mandatory and non-defaulting). It explains the two schools' logic but leaves tool selection entirely to inference.

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