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), so the description's added value is the computational basis (Pushya/Hasta nakshatras, shubha tithis, universal Panchang criteria) and the top-N output shape. It adds useful domain context without contradiction, though it omits output details and any constraints on the search window.

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 single sentence stating purpose and criteria, followed by compact structured metadata (group, cost tier). Little waste, though the bracketed metadata is 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 explained, and the description covers purpose, criteria, and activity scope. It is adequate for invocation, though the sparse parameter documentation is a gap for a 10-param geo/astronomy tool.

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 40%, and the description adds no guidance on the key parameters (latitude, longitude, timezoneOffset, ayanamsa, fields, precision) — all of which materially affect results. Only a vague reference to 'top-N days' touches a parameter, so the description does not compensate for 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?

States a concrete verb+resource ('favourable-window finder') and scopes it precisely as the general/fallback case for when no specific activity applies. This directly distinguishes it from the many activity-specific muhurat siblings (marriage, travel, investment, surgery, etc.).

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?

Explicitly tells the agent when to use it (no specific activity, Sankalpa, prayer, fallback), which by implication routes to the specific muhurat siblings when an activity does apply. No ambiguity about selection.

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