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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the pricing tier ('10 credits, Tier 1'), which is genuinely useful context not present in structured fields, plus the HTTP endpoint. It adds no information about computation quirks or interpretation scope.

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?

One front-loaded sentence plus four bracketed metadata lines; nothing is padded or redundant. The tag format is dense and easy to scan, though the cost/endpoint lines occupy half the space relative to very thin functional content.

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 no explanation, but for a 16-parameter, interpretation-heavy astrological computation with weak schema coverage, the description omits flag semantics, zodiac/house-system selection guidance, and sibling differentiation. It is too thin for a tool of this complexity.

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% across 16 parameters, so the description is expected to compensate — it does not. '[Required: date, time, latitude, longitude]' merely restates the schema's required array, and no guidance is given for houseSystem, zodiacType, withTnp, cosmogram, or the compact-mode fields/precision controls.

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 resource and computation: 'All chart points in 90° cardinal modulus.' An agent can tell this produces a 90° dial listing of chart points, distinct from midpoint pictures or the cosmogram. It stops short of naming the sibling it competes with, and the jargon-heavy phrase 'cardinal modulus' carries most of the meaning.

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 guidance at all — nothing explains when a 90° dial is preferable to astroway_cosmobiology_cosmogram, midpoint_pictures, or sensitive_points, despite a cluster of closely related cosmobiology siblings. The bracketed metadata block only lists groups, endpoint, and cost.

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