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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely non-schema information: the credit cost (10 credits, Tier 1) and the fact that this is a duplicate alias of another endpoint, which helps an agent avoid double-billing for the same computation.

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?

Front-loaded domain term followed by bracketed structured metadata (group, endpoint, required, cost, alias). No filler sentences, though the body is arguably too terse to be self-sufficient.

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 explained, and annotations cover safety. But for a 15-parameter astrological computation with only 33% schema description coverage, the description leaves the caller without an explanation of the technique, the effect of ayanamsa/houseSystem/zodiacType, or how results are shaped.

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%, with 15 parameters including enums for ayanamsa, zodiacType and houseSystem. The description merely restates the four required fields already declared in the schema's required list and adds no syntax, defaults, or meaning for the undocumented parameters, so it neither compensates for the gap nor adds value.

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 the deliverable ('equinoctial contra-antiscia') and, via the alias note, distinguishes itself from the canonical sibling astroway_hellenistic_greenbaum_contra_antiscia. However, it never states what the tool actually computes or returns (positions? aspect pairs?) – it is a bare domain noun phrase with no verb, opaque to anyone not already versed in Greenbaum Hellenistic technique.

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?

There is no when-to-use or when-not guidance. The alias note ('Cursor-friendly alias for ...') implicitly tells the agent either name works, which is marginally useful, but nothing explains when contra-antiscia analysis is the right choice versus siblings like astroway_helg_antiscia_hellenistic or astroway_hellenistic_greenbaum_dodekatemoria.

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