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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is already communicated. The description adds value by disclosing the exact output contract: which bodies are included, what fields each entry contains, and that no interpretation is returned. This goes beyond the annotations without contradicting them.

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 description is longer than average but each sentence contributes: the first specifies the returned data and scope, the second enumerates the exact per-entry fields, and the final sentence clarifies the purely data-oriented nature. Some redundancy exists in listing both the field names and their examples, but it remains efficient and readable.

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?

With no output schema present, the description effectively serves as the output specification, listing all returned fields, their value ranges, and the full set of chart bodies included. Combined with a 100%-covered input schema and safety annotations, an agent has everything needed to call this tool correctly.

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 the schema already documents all parameters clearly. The description does not add parameter-level detail, but it does not need to; the baseline of 3 applies because the schema carries the full parameter documentation 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 starts with a specific action ('Return the birth (sidereal) nakshatra...') and precisely identifies the resource: nakshatra, pada, lord, and degrees for every chart body. It also explicitly differentiates itself from interpretive tools by stating 'Data only — no interpretation is included,' making its scope clear relative to siblings.

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 makes it clear what data will be returned, so an agent can infer that this tool is for raw nakshatra/pada data rather than interpretation or synthesis. However, it provides no explicit when-to-use guidance, no exclusions, and does not name or contrast any sibling tool, leaving selection to inference.

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