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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely new behavioral context the annotations do not: the frame is sidereal (not tropical), the input domain is bounded 0..360, and the call is priced at 20 credits (Tier 2), which is real cost-awareness for an agent.

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?

Two tight sentences, front-loaded with what is returned before the use case, followed by compact group/cost tags. No filler; the only mild waste is restating the 0..360 range that the schema already enforces.

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 described, and the two optional compact-mode params are schema-documented. The description supplies purpose, frame, and cost. The remaining gap is selection context against the near-identical KP sub-lord sibling, which is not addressed.

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 coverage is 67% — 'fields' and 'precision' are documented in the schema, while 'longitude' has only min/max bounds and no description. The description partially compensates by specifying that the longitude is sidereal, which the schema does not say, but it adds nothing about units/format beyond the 0..360 bound already in the schema.

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 and resource — it 'Returns the full sub-lord chain (sign/star/sub/sub-sub)' — and pins the input domain to 'any sidereal longitude 0..360', which is concrete and testable. It does not, however, differentiate itself from the very similarly named sibling astroway_vedic_kp_sub_lords, so an agent must infer that this one is longitude-addressable while that one is chart-based.

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?

It offers a usage context ('useful for transit-trigger and dasha-bhukti exact-moment analysis'), which implies when the tool is applicable. But it gives no when-not guidance and never names an alternative (e.g. astroway_vedic_kp_sub_lords for chart-based lookups), so routing between the two KP sub-lord tools 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.