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

Annotations already declare readOnly=true, idempotent=true, destructive=false, openWorld=false, so the safety profile is fully covered by structured data. The description adds domain behavior (which planets are included/excluded, the seed nakshatra, the period distribution) that is useful context but says nothing about return shape, time span coverage, or how the Mahadasha list is bounded — gaps that the output schema presumably fills.

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 domain facts are front-loaded and information-dense, but the exhaustive sequence enumeration Sun(11)→...→Venus(18) reads like a data dump that arguably belongs in the output rather than the selection description, and the final sentence trails off mid-word, hurting structure.

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 not be explained, and the description does supply the domain meaning an agent needs to understand what the tool computes. It is nonetheless incomplete: no sibling routing, no explicit statement of what comes back, and a truncated applicability rule.

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 deeply documented `body` object already explains birth-data requirements, ayanamsa, timezone handling, plus the compact-mode `fields`/`precision` params. The description adds no parameter-level syntax or constraints, 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?

The description names a specific resource — the Shodashottari Mahadasha cycle — and pins down its defining details (116-year cycle, BPHS Adhyaya 46, planet sequence). However, it never states the operation explicitly (that it returns the Mahadasha-level periods) and does nothing to distinguish itself from the sibling shodashottari_antar/pratyantar/prana/sookshma tools; the agent must infer the 'maha' level from the name alone.

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 a partial applicability condition ('applicable when lagna in Chandra hora during Krishna paksha'), which is genuine domain-level when-to-use guidance, but the sentence is truncated and there is no routing guidance among the four other Shodashottari depth-level siblings. Usage is implied rather than stated.

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