> ## Documentation Index > Fetch the complete documentation index at: https://docs-test.symmetry.com/llms.txt > Use this file to discover all available pages before exploring further. # Generate AI-powered tax calculation explanations > Accepts 1-10 tax IDs with a PayCalc context or STE session and returns employee-friendly explanations ## OpenAPI ````yaml /ste/api-reference/stl-api.yaml post /v1/explain openapi: 3.1.0 info: title: Symmetry Tax Logic API description: >- NOTE: All `/v1/*` endpoints require a Bearer token. **To authenticate:** call `GET /authentication/login` on the Symmetry API with your API key in the `api-key` header, then use the returned `accessToken` as the Bearer token below. contact: name: Symmetry Software url: https://www.symmetry.com/ email: support@symmetry.com license: name: Terms of Use url: https://www.symmetry.com/terms version: 2026.7.1 servers: - url: https://api.symmetry.com/stl security: - BearerAuth: [] tags: - name: Symmetry Tax Logic description: >- Generate AI-powered tax calculation explanations using the Symmetry Tax Engine paths: /v1/explain: post: tags: - Symmetry Tax Logic summary: Generate AI-powered tax calculation explanations description: >- Accepts 1-10 tax IDs with a PayCalc context or STE session and returns employee-friendly explanations operationId: explain_tax_v1_v1_explain_post requestBody: content: application/json: schema: $ref: '#/components/schemas/ExplainInput' required: true responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/ExplainOutput' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' components: schemas: ExplainInput: properties: taxIds: anyOf: - type: string - items: type: string type: array title: Taxids description: >- Tax ID(s) to analyze. String for single tax, array for multiple (max 10) context: $ref: '#/components/schemas/PayCalcContext' description: PayCalc context or session data type: object required: - taxIds - context title: ExplainInput description: >- Input for tax calculation explanation. Supports 1-10 tax IDs per request. examples: - context: payCalc: employeeID: employee 1 payrollRunParameters: payDate: '2020-01-01' payPeriodNumber: 0 payPeriodsPerYear: 52 taxJurisdictionParms: [] wages: [] taxIds: 00-000-0000-FICA-000 - context: payCalc: employeeID: employee 1 payrollRunParameters: payDate: '2020-01-01' payPeriodNumber: 0 payPeriodsPerYear: 52 taxJurisdictionParms: [] wages: [] taxIds: - 00-000-0000-FICA-000 - 00-000-0000-MEDI-000 - context: session: base64-encoded-session-string... taxIds: 00-000-0000-FICA-000 ExplainOutput: properties: id: type: string title: Id description: Conversation ID for the entire request summary: anyOf: - type: string - type: 'null' title: Summary description: >- Overall narrative summary of all taxes (only present for multiple taxes) results: items: $ref: '#/components/schemas/TaxExplanationResult' type: array title: Results description: >- Individual results for each tax ID (always an array, even for single tax) ai_disclosure: type: string title: Ai Disclosure description: Static AI-generated content disclaimer for client display (FR-7) default: >- This explanation is generated using AI and is provided for informational purposes only. It does not constitute tax, legal, or financial advice. AI can make mistakes. type: object required: - id - results title: ExplainOutput description: |- Response for tax explanation requests. Always returns a results array (even for a single tax). Summary is populated when 2+ taxes are requested. examples: - ai_disclosure: >- This explanation is generated using AI and is provided for informational purposes only. It does not constitute tax, legal, or financial advice. AI can make mistakes. id: 01KGJGT4J1798EX9TCJVDFHDZ9 results: - response: Your Social Security Tax is **$477.96**... taxId: 00-000-0000-FICA-000 usage: input_tokens: 56549 output_tokens: 136 - ai_disclosure: >- This explanation is generated using AI and is provided for informational purposes only. It does not constitute tax, legal, or financial advice. AI can make mistakes. id: 01KGJGT4J1798EX9TCJVDFHDZ9 results: - response: Your Social Security Tax is **$477.96**... taxId: 00-000-0000-FICA-000 usage: input_tokens: 56549 output_tokens: 136 - response: Your Medicare Tax is **$111.78**... taxId: 00-000-0000-MEDI-000 usage: input_tokens: 54321 output_tokens: 98 summary: Your paycheck has 3 federal taxes totaling **$785.42**... - ai_disclosure: >- This explanation is generated using AI and is provided for informational purposes only. It does not constitute tax, legal, or financial advice. AI can make mistakes. id: 01KGJGT4J1798EX9TCJVDFHDZ9 results: - response: Your Social Security Tax is **$477.96**... taxId: 00-000-0000-FICA-000 usage: input_tokens: 56549 output_tokens: 136 - error: Tax ID not found in profiler output taxId: 99-999-9999-INVALID-000 HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError PayCalcContext: properties: payCalc: anyOf: - additionalProperties: true type: object - type: 'null' title: Paycalc description: >- Single employee PayCalc object (flat structure - no PayCalcRequest wrapper) session: anyOf: - type: string - type: 'null' title: Session description: Base64-encoded STE session string type: object title: PayCalcContext description: |- Context containing a single employee's payCalc data OR a session string. Provide exactly one of payCalc or session. TaxExplanationResult: properties: taxId: type: string title: Taxid description: Tax ID that was processed response: anyOf: - type: string - type: 'null' title: Response description: AI explanation (only present on success) usage: anyOf: - $ref: '#/components/schemas/TokenUsage' - type: 'null' description: Token usage (only present on success) error: anyOf: - type: string - type: 'null' title: Error description: Error message (only present on failure) type: object required: - taxId title: TaxExplanationResult description: |- Single tax explanation result (success or failure). Success result includes: taxId, response, usage Error result includes: taxId, error examples: - response: Your Social Security Tax is **$477.96**... taxId: 00-000-0000-FICA-000 usage: input_tokens: 56549 output_tokens: 136 - error: Tax ID not found in the provided payroll data taxId: 99-999-9999-INVALID-000 ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type type: object required: - loc - msg - type title: ValidationError TokenUsage: properties: input_tokens: type: integer title: Input Tokens description: Number of input tokens sent to the model output_tokens: type: integer title: Output Tokens description: Number of output tokens generated by the model type: object required: - input_tokens - output_tokens title: TokenUsage description: Token usage statistics from the LLM invocation. securitySchemes: BearerAuth: type: http scheme: bearer description: >- Obtain a token by calling GET /authentication/login with your Symmetry API key in the api-key header. Paste the accessToken value here. ````