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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds value by enumerating what is computed and that it is a bundled read, but it never states the prerequisites (birth date/time and place or coordinates for both people) that drive the call.

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?

A single dense sentence with no filler, and the highest-value information (the two compatibility systems and Kuja evidence) is front-loaded. It could be marginally tighter, but nothing is wasted.

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 restated, and annotations cover safety. However, for a 6-parameter nested tool with 17% schema coverage, the description gives an agent no guidance on the required birth/geo inputs or the years, startDate, muhurta, and language parameters, leaving real gaps before invocation.

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 17% across 6 parameters, so the description is required to compensate and does not. Only 'each person' loosely signals the bride/groom objects, and 'marriage-planning windows' only hints at the muhurta parameter; startDate, years, and the language enum are left unexplained.

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 names a concrete, specific output bundle: Ashtakoota and Porutham compatibility, Kuja evidence, per-chart summaries, and marriage-planning windows, so an agent knows exactly what this tool produces. It implicitly distinguishes itself from calculate_compatibility and find_marriage_windows by framing the result as a combined one-call bundle, but it never names or contrasts those siblings directly.

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 phrase 'in one call' implies the intended context: use this when you want compatibility plus planning windows together rather than assembling several single-purpose tools. There is no explicit when-to-use, no exclusions, and no named alternatives, so the guidance stays at the implied level.

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