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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered by structured data. The description adds the domain rule being checked and a cost/tier indicator (20 credits, Tier 2), which is useful context an agent can't get from annotations, but it says nothing about what the response contains or how the presence/absence result is shaped.

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 short lines with the yoga criterion front-loaded and cost/group metadata fenced off into bracketed tags. No filler, though the second sentence ('one of the most-cited classical combinations') is decorative rather than operational.

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 don't need explanation, and the cost tier is disclosed. However, for a 15-parameter calculation tool with low schema coverage, the description leaves the agent without any sense of which inputs drive the result or when to prefer this single-yoga tool over the aggregate yoga tools.

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 33% across 15 parameters, and the description adds zero parameter-level information — no hint about which inputs are required (date, time, latitude, longitude) or how ayanamsa/houseSystem affect the yoga calculation. The description does not compensate for the coverage gap.

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 the specific yoga (Gajakesari) and gives its exact technical criterion (Jupiter in a kendra — 1, 4, 7, 10 — from the Moon), which pins down precisely what the tool evaluates and distinguishes it from generic yoga tools like parashara_full. The verb is only implied (it doesn't literally say 'detects/reports'), but the resource and scope are unambiguous.

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 statement of when to call this instead of the many sibling yoga tools (parashara_full, pancha_mahapurusha, jaimini_*). The agent gets a definition of the yoga but no routing guidance or prerequisites beyond the cost note.

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