Dashas: Vimshottari Mahadasha

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuine domain behavior — the truncation of the first period by elapsed fraction in the Moon's nakshatra — and the cost tier, but says nothing about output shape, period boundaries or time handling.

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 focused sentences front-load the key definition, followed by a compact metadata block (group, endpoint, cost) that is useful, not filler. The planet enumeration is slightly listy but does convey the sequence order, so little is wasted.

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, return values need not be described, and the rich body schema plus safe annotations carry the mechanics. The definition is complete enough for an agent to call it on a birth chart, with only the targetDate semantics and sibling routing left to inference.

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 100% and the nested body schema documents date/time/coords/timezone extensively, so the baseline of 3 applies. The description adds nothing about parameters, notably leaving the optional targetDate/targetTime/targetTzOffset trio unexplained — whether they shift the dasha listing to a future moment is not addressed anywhere.

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 the exact resource the tool returns — the canonical Vimshottari Mahadasha sequence — and specifies its defining properties (9-planet order, 120-year cycle, start from the Moon's nakshatra lord, truncated first period). However, it never explicitly separates itself from the many sub-period siblings (vimshottari_antar, _pratyantar, _sookshma); the agent must infer 'maha' = top level.

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?

'Canonical' implies this is the default Vimshottari view, which is a weak usage signal. There is no statement of when to choose this over ashtottari/yogini/chara dashas or over the antar/prana drill-down tools, and no prerequisites are stated (birth data requirement is inferable only from the schema).

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