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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely non-annotation context: the 20-credit Tier 2 cost, the targetDate default of today UTC, and the computation formula that explains what the returned period lengths mean.

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?

Purpose and scope are front-loaded in the first sentence, the formula follows as supporting detail, and the group/cost tags close it out. No sentence is redundant and nothing is buried.

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?

With an output schema present, return values need no explanation, and the input schema is fully documented. What is missing for a tool embedded in a large dasha family is routing context: nothing tells the agent why to pick Antardasha over Kalachakra pratyantar or over the Vimshottari/Ashtottari equivalents.

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 baseline is 3. The description still adds value by documenting that targetDate defaults to today UTC, a default the schema itself does not state, and by explaining how the depth parameterizes the returned periods. It leaves targetTime and targetTzOffset to the schema.

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 gives a specific resource (Kalachakra Antardasha) with an explicit level and scope: '9 sub-periods of the running MD at targetDate'. The formula for the sign-level sub-period pins down what an Antardasha is in this system. It does not, however, name which sibling depth (maha/pratyantar/sookshma) to use instead, so differentiation relies on the reader knowing the dasha-level convention.

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 or when-not-to-use guidance, and no alternative tool is named despite ten other dasha systems each exposing an `_antar` variant and three other Kalachakra depths existing as siblings. The only usage hint is the targetDate default.

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