Add AGENTS.md SDK agent instructions

AGENTS.md

@@ -0,0 +1,76 @@
+# Veryfi SDK Agent Instructions
+
+These instructions apply to any Veryfi SDK regardless of implementation
+language (Kotlin, Java, PHP, Node.js, Python, C#, etc.). Apply the rules using
+the conventions, tooling, and idioms of the SDK's language.
+
+## Source of truth
+
+The official Veryfi API documentation is:
+
+https://docs.veryfi.com/
+
+When working on API coverage, API methods, parameters, request handling,
+or SDK functionality, the official documentation is the source of truth.
+
+Do not assume the existing SDK represents the complete or current API.
+
+Before implementing or changing an API method:
+
+1. Find the corresponding endpoint in https://docs.veryfi.com/
+2. Read the complete endpoint documentation.
+3. Verify:
+   - HTTP method
+   - API path
+   - path parameters
+   - query parameters
+   - request body parameters
+   - required vs optional parameters
+   - accepted file formats / request encoding
+   - authentication requirements
+   - response structure
+   - async behavior
+   - pagination behavior
+   - examples and documented edge cases
+
+## SDK implementation rules
+
+- Preserve backward compatibility.
+- Do not rename or remove existing public methods unless explicitly requested.
+- Follow the architecture and conventions already used in this repository.
+- Reuse the existing HTTP client and authentication implementation.
+- Do not introduce another HTTP library.
+- Add tests for every new endpoint.
+- Add tests for newly supported parameters.
+- Update the language's inline API documentation and type definitions/signatures
+  where applicable (for example KDoc for Kotlin, Javadoc for Java, PHPDoc for
+  PHP, JSDoc / TypeScript definitions for Node.js, docstrings/type hints for
+  Python).
+- Update README examples for newly exposed functionality.
+
+## API coverage analysis
+
+When asked to analyze API coverage:
+
+Do not immediately implement code.
+
+First compare the complete public Veryfi API documentation against this SDK.
+
+Classify each API operation as:
+
+- IMPLEMENTED
+- PARTIAL
+- MISSING
+- UNCERTAIN
+
+IMPLEMENTED means the SDK exposes the endpoint and supports the currently
+documented parameters.
+
+PARTIAL means the SDK exposes the endpoint but is missing documented
+parameters, options, behavior, or response handling.
+
+MISSING means no public SDK method exposes the operation.
+
+UNCERTAIN means coverage cannot be proven from the repository and documentation.
+
+Always include the documentation URL used to validate each endpoint.