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

Annotations already declare this as a safe, idempotent, non-destructive read (readOnlyHint/idempotentHint/destructiveHint), so the safety profile is covered. The description adds two genuinely useful behavioral facts beyond the schema: the 20-credit Tier 2 cost and the POST endpoint. It does not describe the returned structure, though an output schema exists.

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 core purpose is a single front-loaded sentence, with bracketed metadata for group, endpoint, required inputs, and cost. It is compact and easy to scan. Minor waste in the redundant required-parameter bracket, but overall efficient.

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?

For a 15-parameter tool the definition covers purpose, required inputs, cost, and endpoint, and the output schema carries the return contract, so the agent can call it. What is missing is any guidance on the optional parameters (timezone vs timezoneOffset, ayanamsa, fields) and on when to prefer this over sibling KP tools.

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% across 15 parameters, so the description must compensate and it does not. It merely repeats the four required parameters (date, time, latitude, longitude), which the schema already lists in its required array, and says nothing about the 11 optional parameters such as fields, ayanamsa, timezone, precision, or houseSystem.

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 and resource: it returns the KP sub-lord chain for every cusp plus every planet (lagna, 9 grahas including Ketu). This is clearly more than a tautology. However, it never contrasts itself against close siblings like astroway_vedic_kp_cusps (cusps only) or astroway_vedic_kp_sub_sub_lord (deeper chain), so sibling differentiation is left to inference.

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 gives no when-to-use guidance, no exclusions, and never names an alternative tool. An agent must infer from the title alone that this is the full cusp+planet sub-lord table rather than the cusps-only or sub-sub-lord variant. Only the required-input list and cost are provided, neither of which is usage guidance.

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