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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real value beyond that: cost (20 credits, Tier 2), the endpoint, the default-to-today behavior, and the period-length formula. Cost and default semantics are things annotations cannot express.

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 dense sentences plus metadata tags; the resource and depth are front-loaded and nothing is wasted. The formula is arguably jargon but it earns its place by clarifying the antardasha computation.

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?

Output schema exists, so return values need no explanation. The description supplies cost, endpoint, default date behavior, and result count (9 sub-periods). The only gap is an explicit pointer to the sibling depth levels for choosing this tool correctly.

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 schema already documents the nested birth body, fields, and precision parameters. The description only adds the `targetDate` default (today UTC) and the internal formula, so the baseline 3 is appropriate rather than a higher score.

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+resource: 'Kalachakra Antardasha: 9 sub-periods of the running MD at targetDate'. The depth level (sub-periods of the running MD) implicitly distinguishes it from the maha/pratyantar/prana/sookshma siblings, though it never names them. Clear but not explicitly differentiated from siblings.

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?

Implies usage via 'at `targetDate` (default today UTC)', giving a default when the agent omits the date. But there is no explicit guidance on when to choose antardasha over the neighbouring depth levels (maha, pratyantar, prana, sookshma), which is the key decision an agent faces with ~70 siblings.

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