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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, and the description adds real domain behavior: Savya/Apasavya direction from nakshatra group, paramayu varying 100/85/83/86 years per pada, and truncation of the first Mahadasha by the elapsed pada fraction. These are non-obvious traits an agent could not derive from structured fields.

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?

Front-loaded with the defining clause, then the mechanics, then the return shape, in one tight paragraph with no filler. Slightly dense/run-on with parenthetical jargon, but every sentence carries information.

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, the description needn't enumerate return fields, but it still states what is returned (9 Mahadashas of the running cycle, first truncated). For a read-only Tier-2 computation tool this is close to complete; only explicit sibling routing is missing.

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 nested birth-data schema already documents date/time/latitude/longitude, timezone handling, and the fields precision compact-mode parameter. The description adds no parameter-level guidance, so the baseline 3 applies.

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 and scope: 'Kalachakra Dasha ... Returns the 9 Mahadashas of the running cycle from birth'. It also disambiguates from the sibling Kalachakra tools (antar/pratyantar/prana/sookshma) by naming the Mahadasha level and from other dasha systems by defining the rasi-dasha rule that lords are signs, not planets.

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 implies the use case (getting Mahadasha-level Kalachakra periods) but never says when to prefer this tool over astroway_vedic_dashas_kalachakra_antar or the other dasha families, nor does it state prerequisites beyond the birth data. Usage is inferable from the name and content, not stated.

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