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

Annotations already declare readOnly, idempotent, non-destructive, so safety is covered. The description adds the cost tier (20 credits, Tier 2) and the exact computed output content, which is useful context, but says nothing about what inputs drive the result (notably which ayanamsa governs the sidereal position) or any limits.

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?

Front-loaded with the essential computation, followed by the output fields and bracketed cost/group metadata. No filler, though the metadata lines are boilerplate rather than tool-specific guidance.

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 re-explained, but for a 15-parameter location/time tool with only 33% schema coverage, no usage guidance, and an ambiguity around sidereal settings, the description leaves too much for the agent to infer.

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%, and the description adds zero parameter semantics. It never mentions required date/time/latitude/longitude, nor the ayanamsa choice that determines a sidereal Nakshatra (Lahiri default) despite that being the single most consequential parameter for this tool's correctness.

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 specific verb+resource: the Moon's sidereal Nakshatra at a given moment, plus the returned sub-fields (Pada 1-4, percent-complete). This is distinct from sibling panchang tools like tithi/yoga/karana, though the description never names those siblings or the full-panchang tool to draw the line explicitly.

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?

No when-to-use, when-not-to-use, or alternative-tool guidance is given. In a family with panchang_full, tithi, yoga, karana, choghadia, rahu_kaal and a standalone nakshatras reference tool, the agent gets no help choosing among them.

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