Dashas: Dwadashottari Mahadasha

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

Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description adds meaningful context beyond them: the lord-year allotments, the omission of Venus, and the fact that periods are returned even when `applicable` is false, which prevents the agent from misreading an inapplicable result as an error.

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 dense sentences front-load the identity of the dasha, then the calculation rule, then the applicability caveat. The year enumeration is compact and load-bearing (it explains the 112-year total), though the BPHS citation adds little for an agent deciding how to call the tool.

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 values need no explanation, and the description still flags `initial.applicable` as the key output signal. For a read-only single-parameter computation tool, what remains is minor routing guidance toward the sibling period-level tools.

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?

There is a single `body` parameter with 100% schema description coverage, including detailed notes on timezone handling, coordinate forms and house-system letters. The description adds nothing about parameters beyond the navamsa applicability field, so the baseline 3 for schema-covered input is appropriate.

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 specific system (Dwadashottari Dasha), its structure (112-year nakshatra cycle of 8 lords) and its source (BPHS 46.27-28), so an agent knows exactly which dasha computation this is. It does not explicitly contrast itself with the antar/prana/pratyantar siblings or other dasha systems, so sibling differentiation is left to the tool name.

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?

It gives a real usage condition: the dasha is given for a lagna in a Venus navamsa, `initial.applicable` reports whether that holds, and periods are computed either way. That tells the agent the call is valid regardless of applicability, but there is no guidance on choosing this system over Vimshottari/Ashtottari or on drilling down into the antar/prana siblings.

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