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

Annotations already declare read-only, idempotent, non-destructive behavior, so the safety profile is covered. The description adds real value beyond them: the equal-share subdivision rule (parent_years / 12), the ordering convention (next sign first, parent sign last per K.N. Rao), and the credit cost.

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 that front-load what is computed before the algorithm detail, plus compact group/cost tags. Minimal waste, though the K.N. Rao attribution and subdivision formula are specialized jargon an outsider must parse.

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 no explanation. Given the read-only annotations and the algorithmic detail provided, an agent has enough to call this correctly; only the routing against sibling dasha levels is missing.

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 carries most parameter meaning; baseline is 3. The description adds only that targetDate defaults to today UTC, leaving targetTime, targetTzOffset, fields and precision untouched.

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 resource (Chara Antardasha) and describes exactly what it computes: the 12 sub-periods of the running Mahadasha. The 'antar' level is clear against the dasha hierarchy, though it never names the sibling levels (chara_pratyantar, chara_prana, chara_sookshma) an agent might confuse it with.

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?

Usage is implied by the timing anchor ('at targetDate, default today UTC') but there is no explicit when-to-use, when-not-to, or routing guidance to the other Chara dasha tools. An agent must infer it from the 'Antardasha' label alone.

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