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 genuinely new behavioral information by promising paisa-exact results, which tells the agent about rounding/quantization behavior absent from the schema. It stops short of describing the exact response shape, which matters with no output schema.

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?

A single dense sentence that front-loads the verb and resource, then layers the two modes and the tax split in dependency order. No filler or restated title text.

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?

Complete enough to call correctly: inputs, defaults, modes, and precision are all clear. The remaining gap is the return shape (whether it returns the split components, total, and rate breakdown), which an agent must infer since no output schema exists.

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 coverage is 100%, with both enum values, defaults, and formats already documented, so the schema carries the load. The description reinforces the semantic mapping (supply → CGST/SGST vs IGST, inclusive vs exclusive pricing) but adds no syntax or edge-case detail beyond what the schema states; baseline 3 applies.

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 and resource (calculate Indian GST) plus the two operations it supports: adding GST to a pre-tax price or extracting it from an inclusive price. The CGST/SGST vs IGST split further distinguishes its domain from all sibling calculators, which cover unrelated finance topics.

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?

Explicitly frames the two usage modes — add GST to a price before tax, or take it out of a GST-inclusive price — and ties intra-state vs inter-state to the correct tax split. It doesn't name sibling tools or state exclusions, but the siblings are unrelated calculators, so the routing risk is low.

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