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

Annotations already declare this readOnlyHint=true and descriptiveHint=false, so the description doesn't need to re-establish that calling it has no destructive side effects. It adds useful details about output content—Nadi/Bhakoot dosha detection, cancellation analysis, and marriage recommendation. However, it does not discuss rate limits, auth requirements, result size, or behavioral limitations; with annotations covering the safety profile, this is adequate but not rich.

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 a single, well-organized sentence that front-loads the main action and payoff, followed by one applicers sentence. Pharmacy phrases like 'accurate' and 'perfect for' are slightly promotional and could be trimmed, but the rest of the information is relevant: kootoor breakdown, doseha details, traditional sourcess, and use cases. It is not bloated or unorganized, so it earns more than a mid score.

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?

There is no output schema, but the description compensates by stating that the result contains a 36-point Guna Milan scale, a breakdown across the 8 kootas, Nadi and Bhakoot dosha detection, cancellation analysis, and a marriage recommendation. For a side-output API with 6 parameters and nested person objects, this is a nearly complete picture. It could further clarify response particle or how errors from incomplete birth data are handled, but the description covers the essential outcome.

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 covers 100% of the 6 parameters, including nested person1/person2 fields, timezone, ayanamsa, language, and compact mode. The description adds only that person1 and person2 are 'between two people,' which is already obvious from the schema. Since the schema carries the parameter-documentation burden and the description doesn't materially add semantic detail, the baseline of 3 is appropriate.

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 verb and resource: 'Calculate detailed Ashtakoot compatibility (Gun Milan) for kundli matching between two people.' It explicitly names the 36-point scale, the 8 kootas, unique doseha analysis, and marriage recommendation. This makes it distinguishable from sibling astronomy endpoints, which handle charts, dongh/birth, panchang, or ayanamsa. The title reinforces the purpose without obscuring it.

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 clearly identifies the ideal use: 'kunderra clustering for marriage, matrimonial platforms, horoscope compatibility, and Vedic matchmaking services.' It does not, however, explicitly say when not to use this tool versus alternatives such as manglik dosha, sadhesati dosha, or individual chart endpoints. Because there are many sibling tools but no explicit exclusion/alternative routing, this is 'clear context, no exclusions'.

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