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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds genuinely behavioral context beyond that: results may include 'boundary warnings' and 'unresolved lineage-specific source keys', signalling partial or flagged output. It stops short of explaining failure modes or how those warnings surface.

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 tight sentences, front-loaded with the returned content and ending with the sibling distinction; no filler. The long comma list of outputs blends computed limbs with caveat fields, which slightly muddies the structure but does not waste words.

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 explaining return values is optional, and the annotations carry the safety profile; the description is complete enough on those axes. Its remaining gap is the parameter branch (place vs explicit coordinates), which the schema's anyOf covers structurally even though the description adds nothing.

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 only 38%, and the description supplies zero parameter guidance — nothing about date/time format, the place-vs-coordinates branch, or the timezoneOffset fallback. With low coverage, the description should compensate but does not, leaving most parameters (date, name, time, latitude, longitude) undocumented.

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 concrete verb (Returns) and enumerates the specific resources computed (Vara, Tithi class, Nakshatra lord, Yoga, Karana, Paksha Bala, plus warnings and unresolved source keys). It explicitly names the sibling it is not ('distinct from daily Panchanga'), so an agent can separate it from get_panchanga without opening either schema.

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 closing sentence routes the agent by contrasting this tool with 'daily Panchanga', implying natal use versus daily use. However, it never states an explicit condition, prerequisite, or 'use X when / use Y when' rule, so the routing is inferred rather than spelled out.

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