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

Annotations already declare readOnly/idempotent/non-destructive, so the safety bar is met. The description adds real behavioral context beyond that: the computation is a rasi-dasha governed by sign lords, direction depends on nakshatra group, cycle length varies per pada, and the first Mahadasha is truncated by elapsed pada fraction. That is substantive, non-obvious disclosure.

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?

The text is dense but front-loaded with the defining characteristic of the dasha, then structure, then return shape. Each clause carries domain information rather than filler, though the trailing truncation ('first MD truncated by elapsed pada-f…') leaves the last sentence dangling.

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 documented input schema, the description need not restate returns or parameters, and it supplies the domain framing an agent needs to interpret results. The only material gap is absent routing to the kalachakra sub-period siblings.

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% and the birth-data schema is richly annotated (timezone, houseSystem, coord validation), so the burden is on the schema. The description adds no parameter-level detail, making baseline 3 correct.

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?

The description names a specific dasha system and immediately characterizes it ('Kalachakra Dasha (rasi-dasha: Mahadasha lords are signs, not planets)'), distinguishing it from planetary dashas like Vimshottari. It also states the return set ('the 9 Mahadashas of the running cycle from birth'), which separates it from the lower-level kalachakra_antar/pratyantar/prana/sookshma siblings without naming them directly.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no sibling is named as an alternative (e.g. kalachakra_antar for sub-periods). The description explains how the system works (Savya/Apasavya direction, paramayu) but never tells an agent which Kalachakra level to pick for a given need.

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