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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the bar is low; the description adds the useful facts that the result is a stability/transition window analysis and that the call costs 50 credits (Tier 3) at POST /v1/hd/sensitivity. It stops short of saying how the perturbation is performed (step size, range of minutes), which is the one behavior an agent would want to know.

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 with the purpose front-loaded, followed by compact metadata lines for group, endpoint, required fields and cost. The required-fields line duplicates the schema's required array, a minor redundancy, but nothing else is wasted.

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-value explanation is not needed, and the safety profile is covered by annotations. However, for a 15-parameter tool at 33% schema coverage, the description leaves the agent unable to tell which optional parameters matter for an HD-type sensitivity run, and it never defines what a 'window' or 'transition' means quantitatively.

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?

15 parameters with only 33% schema description coverage, and the description adds no parameter meaning at all beyond restating the four required fields already declared in the schema's required array. The many optional astrology parameters (zodiacType, houseSystem, ayanamsa/ayanamsaId, cosmogram, precision, fields) are left undocumented here, and the description gives no hint which of them actually influence an HD sensitivity result.

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 a specific verb and resource: analyzing HD chart type/authority sensitivity to birth-time changes, and even previews the return shape ('windows where the chart is stable vs. in transition'). It is clearly distinct from sibling chart-computation tools like astroway_hd_human_design, though it never names an alternative to differentiate against.

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?

Usage is implied rather than stated: an agent can infer this is for validating whether a known birth time is precise enough to fix HD type/authority, but there is no explicit when-to-use, when-not-to-use, or pointer to a sibling when sensitivity is irrelevant.

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