Varga D3: Drekkana

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

Annotations already declare the read-only, idempotent, non-destructive safety profile, and an output schema exists. The description adds genuinely new operational facts: the POST endpoint and a 20-credit (Tier 2) cost, which matters for tool selection. It says nothing about latency, caching, or sidereal defaults.

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?

Tight, front-loaded: the concept comes first, then bracketed metadata for group, endpoint, required inputs and cost. No filler sentences, though the bracket block is somewhat list-like rather than explanatory.

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?

Return values are covered by the output schema and safety by annotations, but for a 13-parameter chart computation with low schema coverage the definition is thin — it never states which ayanamsa/zodiac defaults apply to a Vedic varga or how the optional parameters change the result.

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 23%, so the description should carry more weight, but it merely restates the four required fields already listed in the schema's required array. Nine optional parameters (houseSystem, zodiacType, cosmogram, city, name, ayanamsaId, etc.) get no explanation in the description, leaving the agent to infer Vedic defaults.

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?

Names a specific resource (Drekkana / D3 divisional chart) and glosses its domain meaning (siblings, courage; trinal third-of-sign division), which an agent can map to Vedic varga work. It does not explicitly contrast with the D1/D9/D10 siblings, though the D3 designation in name and title does most of the disambiguation.

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?

The description gives required parameters and cost but no guidance on when to call this versus another varga (D9, D10, etc.) or a full kundli tool. The only routing signal is the implicit D3 label.

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