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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: 10-credit cost with only successful calls charged, a free sandbox key returning a fixed sample, and determinism ('same input always gives the same answer').

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?

Four short sentences are front-loaded with purpose and constraints, followed by one long but high-information example. The example costs length but earns its place by illustrating the deeply nested required arguments; no sentence is filler.

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 an output schema present, return values need no explanation, and the input schema documents all nine parameters. The description covers cost, determinism, place semantics, and an example, leaving only sibling-relative routing unaddressed.

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 baseline is 3; the description still adds value by providing a complete example argument object showing the nested subject/eventPlace shapes, and by stressing that eventPlace (not the subject's birthplace) drives the pañcāṅga computation.

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 (scans/ranks) and resource (auspicious muhūrta windows in a date range), and the second sentence clarifies the ranking basis (the subject's chart). An agent can distinguish this from read-only siblings like get_forecast or resolve_timing from the name-plus-description alone.

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 implies usage (range scanning, ranking windows, cost per call, sandbox behavior) and warns that the pañcāṅga is computed at eventPlace, never the birthplace. However it never names when to prefer this over sibling tools such as resolve_timing or get_forecast, so alternative selection is left to inference.

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