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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows this is a safe read operation. The description adds useful behavioral context like 'complete list' and 'from Ashwini to Revati', but it does not describe response shape, pagination, or any other runtime behavior. This is adequate given the annotations.

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?

Three sentences with no wasted words. The opening sentence front-loads the main 'list all 27' intent, the second sentence enumerates the return fields, and the third sentence gives practical usage context.

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?

The description is rich enough for a list operation with no output schema: it covers the 27-item scope, the exact fields returned, and practical use cases. A minor omission is lack of explicit routing to the ID-based sibling, but the singular/plural distinction and 'complete list' wording make it inferable.

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 enum, defaults, and behavior offall lang and compact parameters are fully documented in the schema. The description adds no parameter details, but that is fine because the schema already carries the burden.

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 states a specific verb and resource: 'Get the complete list of 27 nakshatras (lunar mansions) in Vedic astrology.' It clearly distinguishes this list/sibling from get_vedic_astrology_nakshatras_id by emphasizing completeness ('all 27', 'from Ashwini to Revati').

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 description gives concrete use cases: 'nakshatra lookup tables, dasha period calculations, muhurta selection, and astrology app reference data.' It does not explicitly mention when not to use it or point to the ID variant, but the use context is clear.

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