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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description usefully discloses the computational scope: carefully bounded slow-transit periods over a future interval plus Vimshottari intersections. It adds no auth, performance, or output-format context.

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 led by the verb 'Returns' with no filler. It is dense with domain jargon but every clause names a distinct output, so little 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 structure needn't be explained, and the description enumerates the main outputs. However, for an 11-parameter tool it omits why both a natal birth moment and a future interval are required, leaving a real gap.

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 9% across 11 parameters, so the description must compensate but largely does not. Only 'selected future interval' loosely maps to startDate/years; the seven required natal inputs (date, time, place, latitude, longitude, timezoneOffset) and their relationship to the interval are never explained.

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 output: Saturn/Jupiter/Rahu/Ketu sidereal sign periods, Sade Sati/Dhaiya ranges, and Vimshottari intersections. An agent can tell what it computes, but nothing distinguishes it from close siblings like calculate_ingress_timeline, calculate_gochara, or fuse_timing, which likely produce overlapping transit data.

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?

No when-to-use, when-not, or alternative guidance is given. With many transit/timing siblings (calculate_gochara, analyze_transit_activation, get_timing_context, query_vimshottari_date), the agent has no basis from the description to choose this tool over them.

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