Resolve the Indian state/UT name from a GSTIN's first 2 characters (the TIN state code). Accepts a full GSTIN or just the 2-char prefix. Returns {state_code, state_name}, e.g. ('27', 'Maharashtra').
| Name | Required | Description | Default |
|---|---|---|---|
| gstin | Yes | Full GSTIN or 2-char state-code prefix. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description bears full responsibility. It outlines core behavior (accepts full GSTIN or prefix, returns state code and name) but omits error handling or edge cases (e.g., invalid prefix).
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?
The description is two sentences, front-loaded with the action, and includes an example output. Every sentence adds value without redundancy.
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?
For a simple 1-parameter lookup with no output schema, the description covers essential behavior (input, output format, example). It is mostly complete, though missing error or validation details.
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?
The single parameter 'gstin' has 100% schema coverage. The description reiterates the schema's text without adding new meaning, meriting the baseline score of 3.
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 clearly states the tool resolves Indian state/UT name from GSTIN's first 2 characters, with specific input and output examples. It is distinct from siblings like extract_pan and validate_gstin.
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 does not explicitly state when to use this tool versus alternatives. It implies usage for state resolution but lacks exclusion criteria or context-based guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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Each tool has a clearly distinct purpose: extracting PAN, resolving state, and full validation. No overlap or ambiguity.
All tool names follow a consistent verb_noun pattern with snake_case (extract_pan, state_from_gstin, validate_gstin).
Three tools is slightly below typical range but well-scoped for a focused validation server; each tool is essential and not redundant.
Covers the main validation needs (format, state, PAN, check digit). Minor gaps like a dedicated check-digit tool or batch processing exist but are non-essential.