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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), so the description's job is to add domain behavior — and it does: Ketu exclusion, the block-based nakshatra anchoring at Ardra, and the BPHS 46.23 applicability condition (day Krishna OR night Shukla). The credit cost (20, Tier 2) adds practical context, though nothing is said about performance or time range of returned periods.

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 essential identification (108-year Ashtottari, Ardradi) and compressed into a few dense but information-bearing sentences. The period and nakshatra enumerations are verbose yet directly relevant to the calculation, 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?

An output schema exists, so return-value documentation is not required, and the description still notes the applicability flag it emits. Combined with annotations covering safety, the remaining gap is purely the absence of usage/routing guidance among dashed 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%, so birth-data fields, timezone rules, ayanamsa and compact-mode fields are all documented in the schema itself. The description adds no parameter-level meaning beyond that, which is the expected baseline when the schema does the heavy lifting.

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 calculation: Ashtottari Mahadasha under the Ardradi tradition, with planetary periods and nakshatra mapping enumerated. An agent understands what is being computed. It does not, however, distinguish itself from the ashtottari_antar/pratyantar/sookshma/prana siblings that share the same scheme at sub-period levels.

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?

No when-to-use guidance and no mention of the four sibling tools at deeper dasha levels (antar, pratyantar, sookshma, prana) that an agent must choose between. The only implicit cue is 'maha' in the name, which is not explained in the description.

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