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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds the genuinely useful cost signal (100 credits, Tier 4), which matters for budget-aware planning, but says nothing about computation weight, response size, or how wide a date range is practical.

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?

A single front-loaded sentence that defines the deliverable, followed by compact metadata lines for group and cost. Nothing is padded, though the cost/group lines are structured metadata rather than descriptive value.

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 the 100-credit cost is disclosed. What is missing is any guidance on choosing this over sibling prognostics tools and any sense of practical date-range or orb boundaries, leaving the agent to guess at invocation strategy.

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 100%, so the nested natal/startDate/endDate/maxOrb/aspectAngles/transitPlanetIds parameters are already documented. The description indirectly maps to them ('month-by-month' implies the date range, 'ingresses and partile hits' implies aspect angles plus orb) but adds no explicit syntax or defaults beyond the schema. Baseline 3.

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 (build) and resource (transit calendar) with scope (month-by-month for a natal chart) and content (aspect ingresses and partile hits). An agent can distinguish it from a generic transit tool by the calendar/ingress framing, though it never names its closest siblings (astroway_prognostics_transits, astroway_prognostics_forecast_calendar).

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 says what the output is but not when to choose it over astroway_prognostics_transits or astroway_prognostics_forecast_calendar, and gives no prerequisites beyond the natal chart. The 'Group: Prognostics' tag and cost line are the only routing hints, which the agent must infer from.

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