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 useful scope context (which grahas are included, future-only interval), but says nothing about how crossings are reported or ordering of results.

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 tight sentence with no filler, and the scoping detail (bodies plus interval) is front-loaded. Nothing needs trimming.

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 for a 9-parameter tool with six required fields and zero schema documentation, the description omits any parameter guidance or usage routing. The result is too thin to call the tool confidently without opening the schema.

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 0% across 9 parameters, and the description compensates for none of them: date, days, place, latitude, longitude, timezoneOffset, timezone and language are all left unexplained. 'Explicit future interval' only loosely gestures at date/days and adds no format, bounds, or coordinate-system detail.

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 (finds sign-boundary crossings), names the exact bodies covered (Sun through Saturn and the lunar nodes), and the temporal scope (explicit future interval). It does not, however, distinguish itself from close siblings such as build_slow_transit_calendar or calculate_gochara, which also deal with planetary movement over time.

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, no exclusions, and no naming of alternatives. The phrase 'explicit future interval' implies a forward-looking constraint but never states that past dates are rejected or when another transit tool would be preferable.

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