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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds genuinely useful context in the form of the credit cost (20 credits, Tier 2) and the return contents, but says nothing about the required coordinate/date inputs or response shape.

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 compact lines that are front-loaded with the core definition, followed by tidy group and cost tags. No wasted prose, though the definition could be slightly more explicit about scope.

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 the return format needn't be spelled out, and the description wisely names the key outputs. However, with 15 inputs, low schema coverage, and no sibling routing, the definition is only marginally complete for a niche Vedic endpoint.

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 33% across 15 parameters, so the schema leaves many parameters (city, name, cosmogram, zodiacType, ayanamsaId, houseSystem) undocumented. The description compensates with nothing about parameters, explaining only the astronomical output, so it fails to fill the coverage gap.

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 gives a precise definition of the resource ('Lunar day (1-30): Moon-Sun elongation / 12°') and lists the returned values (paksha, tithi name, % complete), so an agent knows exactly what computation this is. It does not, however, distinguish itself from sibling panchang tools such as panchang_full, panchang_karana, or panchang_yoga.

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 no statement of when to use this tool versus the many other vedic panchang siblings, nor any prerequisite guidance (e.g., that date/time/latitude/longitude are required). The only contextual note is a cost tag, which is not usage guidance.

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