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

Annotations already declare the full safety profile (readOnly, idempotent, non-destructive, closed-world), so the description is not required to explain mutation risk. It does add two useful operational facts beyond the annotations: the POST endpoint and the 10-credit Tier 1 cost, which matters for cost-aware agents. It says nothing about rate limits, payload size, or response shape.

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 definition is tightly front-loaded: the domain concept leads, followed by bracketed metadata lines that are easy to scan. Nothing is padded, though the bracketed lines occupy space that could have carried the missing usage and parameter guidance.

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, but this is a 16-parameter tool with three enums and a sophisticated sidereal/house-system surface, and the description provides no orientation to any of it. For a tool of this complexity, the bare required-parameter list and cost note are not enough for an agent to invoke it confidently.

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 31%, well under the threshold where the schema can carry the burden, so the description needs to compensate and does not. It merely restates the four required parameters already marked required in the schema, leaving the twelve optional parameters (houseSystem enum, withTnp, cosmogram, ayanamsa, zodiacType, fields, precision) unexplained anywhere except the schema's own text.

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?

"A=B/C structures with sentence form" names a domain-specific artifact and its output shape, which is slightly more than the title alone, but it never states the plain-language operation (compute midpoint pictures) or the subject of the computation. It also fails to distinguish itself from close siblings like astroway_cosmobiology_transit_midpoints or astroway_cosmobiology_cosmogram, whose names overlap heavily in this same group.

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 lists required inputs and a cost tier but gives no when-to-use guidance and no alternatives. An agent choosing among nine cosmobiology siblings gets no signal about which produces midpoint pictures versus dials, cosmograms, or transit midpoints.

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