> ## Documentation Index > Fetch the complete documentation index at: https://docs.decodahealth.com/llms.txt > Use this file to discover all available pages before exploring further. # List Candidate Modifiers > Candidate (NOT eligible) modifiers for a CPT/HCPCS code. Narrows the Super Bill editor's modifier picker to the union of: * PROCEDURE modifiers the AMA CPT Modifier Crosswalk associates with the line's code (``cpt_modifier`` -> ``modifier`` for the label), and * every INSURANCE modifier, regardless of code. The union exists because the crosswalk only catalogs *procedure* modifiers — facts about how a procedure was performed (26 professional component, 50 bilateral). INSURANCE modifiers (the CMS ABN family: GA/GX/GY/GZ) instead describe whether the PAYER covers the line, which turns on the patient's plan rather than the procedure — so no code->modifier crosswalk can express them, and their absence from it is guaranteed rather than evidence of invalidity. Crosswalk-only candidates hid GY from chiropractic billers, who need it on essentially every line that isn't 98940/98941/98942. Final correctness still depends on payer, documentation, POS, provider type, the other claim lines, and encounter context — so these are candidates, and the picker keeps its free-type escape. An unknown code returns the insurance modifiers (not ``[]``): they are code-independent, and free-typed lines carrying codes absent from the licensed ``cpt`` catalog (e.g. J-codes) are exactly where a biller reaches for GY. Each row carries ``crosswalked`` — whether the crosswalk pairs it with THIS code, as opposed to being present only because it is an insurance modifier. The picker warns about an off-list modifier only for a code the crosswalk actually has rows for; because insurance modifiers make the list never-empty, "no rows for this code" is no longer an empty list and needs this flag to stay detectable. It is derived per request, not the modifier's stored type. ## OpenAPI ````yaml get /medical-codes/cpt/{code}/candidate-modifiers openapi: 3.1.0 info: title: Decoda API description: External API documentation for the Decoda Health platform. version: '1.0' servers: [] security: [] paths: /medical-codes/cpt/{code}/candidate-modifiers: get: tags: - Medical Codes summary: List Candidate Modifiers description: >- Candidate (NOT eligible) modifiers for a CPT/HCPCS code. Narrows the Super Bill editor's modifier picker to the union of: * PROCEDURE modifiers the AMA CPT Modifier Crosswalk associates with the line's code (``cpt_modifier`` -> ``modifier`` for the label), and * every INSURANCE modifier, regardless of code. The union exists because the crosswalk only catalogs *procedure* modifiers — facts about how a procedure was performed (26 professional component, 50 bilateral). INSURANCE modifiers (the CMS ABN family: GA/GX/GY/GZ) instead describe whether the PAYER covers the line, which turns on the patient's plan rather than the procedure — so no code->modifier crosswalk can express them, and their absence from it is guaranteed rather than evidence of invalidity. Crosswalk-only candidates hid GY from chiropractic billers, who need it on essentially every line that isn't 98940/98941/98942. Final correctness still depends on payer, documentation, POS, provider type, the other claim lines, and encounter context — so these are candidates, and the picker keeps its free-type escape. An unknown code returns the insurance modifiers (not ``[]``): they are code-independent, and free-typed lines carrying codes absent from the licensed ``cpt`` catalog (e.g. J-codes) are exactly where a biller reaches for GY. Each row carries ``crosswalked`` — whether the crosswalk pairs it with THIS code, as opposed to being present only because it is an insurance modifier. The picker warns about an off-list modifier only for a code the crosswalk actually has rows for; because insurance modifiers make the list never-empty, "no rows for this code" is no longer an empty list and needs this flag to stay detectable. It is derived per request, not the modifier's stored type. operationId: >- list_candidate_modifiers_medical_codes_cpt__code__candidate_modifiers_get parameters: - name: TENANT in: header required: true schema: type: string title: Tenant description: The tenant you are making this request on behalf of - name: API-KEY in: header required: true schema: type: string title: Api-Key description: Your api key - name: code in: path required: true schema: type: string title: Code responses: '200': description: Successful Response content: application/json: schema: type: array items: $ref: '#/components/schemas/CandidateModifier' title: >- Response List Candidate Modifiers Medical Codes Cpt Code Candidate Modifiers Get '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' components: schemas: CandidateModifier: properties: code: type: string title: Code label: type: string title: Label crosswalked: type: boolean title: Crosswalked type: object required: - code - label - crosswalked title: CandidateModifier description: >- A *candidate* modifier for a CPT/HCPCS code — the modifiers the AMA CPT Modifier Crosswalk associates with the code, plus the insurance modifiers, which apply to every code. Narrows the Super Bill picker, not an eligibility verdict; ``label`` is the modifier's description. The picker keeps its free-type escape, so an off-list modifier can still be added. HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type input: title: Input ctx: type: object title: Context type: object required: - loc - msg - type title: ValidationError ````