> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pidgeon.health/llms.txt
> Use this file to discover all available pages before exploring further.

# Message Generation

> Generate realistic HL7, FHIR, and NCPDP test messages in seconds — no manual creation, no production data copying, no compliance risk.

Every code uses real reference datasets — ICD-10, LOINC, NDC, SNOMED CT, CVX, RxNorm, HCPCS — so generated messages pass downstream validation the same way production data would.

## Supported Standards

<CodeGroup>
  ```bash HL7 v2 theme={null}
  pidgeon generate ADT^A01 --count 5
  pidgeon generate ORU^R01 --count 3
  pidgeon generate ORM^O01
  ```

  ```bash FHIR R4 theme={null}
  pidgeon generate Patient --count 5
  pidgeon generate Observation
  pidgeon generate Bundle
  ```

  ```bash NCPDP SCRIPT theme={null}
  # NCPDP is license-gated — see below
  pidgeon generate NewRx
  pidgeon generate RxFill
  pidgeon generate CancelRx
  ```
</CodeGroup>

<Note>HL7 v2 and FHIR R4 generation are free. NCPDP SCRIPT generation is **closed by default**: it requires confirming NCPDP membership and installing the licensed standards package (`pidgeon data install ncpdp-script --accept-license`). Until then the CLI and apps report NCPDP as license-required rather than emitting a message.</Note>

## HL7 v2 Coverage

Post's HL7 v2 parsing and generation is structurally broad, but the number that matters is what's proven end-to-end: generate → validate → round-trip against the published spec. That verified set is **279 HL7 message-type × version combinations** — 38 message types, each across some or all of HL7 v2.3 through v2.8 — from the engine's own runtime capability matrix, not a hand-maintained table:

```bash theme={null}
pidgeon --output-format json capabilities --standard hl7
```

<AccordionGroup>
  <Accordion title="ADT — Admit, Discharge, Transfer" icon="bed">
    `ADT^A01` Admission, `ADT^A02` Transfer, `ADT^A03` Discharge, `ADT^A04` Registration, `ADT^A05` Pre-admit, `ADT^A08` Update patient info, `ADT^A11` Cancel admit, `ADT^A12` Cancel transfer, `ADT^A13` Cancel discharge
  </Accordion>

  <Accordion title="Orders & Results" icon="flask">
    `ORM^O01` General order, `ORU^R01` Observation result, `OML^O21` Lab order (multi-order), `RSP^K11`/`K21`/`K22` Query responses, `QBP^Q11`/`Q21`/`Q22` Query by parameter
  </Accordion>

  <Accordion title="RDE / RGV / RAS — Pharmacy" icon="pills">
    `RDE^O11` Pharmacy/treatment encoded order, `RDE^O25` Pharmacy/treatment refill authorization, `RGV^O15` Pharmacy/treatment give, `RAS^O17` Pharmacy/treatment administration
  </Accordion>

  <Accordion title="SIU — Scheduling" icon="calendar">
    `SIU^S12` New appointment, `SIU^S13` Request rescheduling, `SIU^S14` Modification notification, `SIU^S15` Cancellation notification, `SIU^S17` Deletion notification
  </Accordion>

  <Accordion title="MDM — Medical Documents" icon="file-medical">
    `MDM^T02` Original with content, `MDM^T04`/`T06`/`T08`/`T10` document addenda, status changes, and replacements
  </Accordion>

  <Accordion title="BAR / DFT — Financial & Billing" icon="file-invoice-dollar">
    `BAR^P01` Add patient account, `BAR^P02` Purge patient account, `BAR^P05` Update account, `DFT^P03` Post detail financial transaction
  </Accordion>

  <Accordion title="VXU — Immunization" icon="syringe">
    `VXU^V04` Unsolicited vaccination update
  </Accordion>

  <Accordion title="ACK — Acknowledgment" icon="check">
    `ACK` general acknowledgment
  </Accordion>
</AccordionGroup>

<Tip>Shell-safe syntax is supported: `ADT-A01`, `ADT_A01`, and `ADT.A01` all work as alternatives to `ADT^A01`.</Tip>

<Note>This list is the current spec-validated set, not a ceiling — Post's parser handles a broader range of HL7 v2 structurally. Run `pidgeon capabilities` for the live matrix rather than trusting this page to stay current.</Note>

## FHIR R4 Resources

**24 resource types** at spec-validated level, spanning clinical, administrative, and financial domains:

<AccordionGroup>
  <Accordion title="Patient & Demographics" icon="user">
    Patient, RelatedPerson
  </Accordion>

  <Accordion title="Clinical" icon="stethoscope">
    Observation, DiagnosticReport, Condition, AllergyIntolerance, Immunization
  </Accordion>

  <Accordion title="Medications & Procedures" icon="pills">
    Medication, MedicationRequest, MedicationAdministration, MedicationDispense, Procedure, ServiceRequest
  </Accordion>

  <Accordion title="Care Management" icon="clipboard-list">
    Encounter, CareTeam, CarePlan
  </Accordion>

  <Accordion title="Administrative" icon="building">
    Organization, Location, Practitioner, PractitionerRole
  </Accordion>

  <Accordion title="Infrastructure" icon="layer-group">
    Bundle, DocumentReference
  </Accordion>

  <Accordion title="Financial" icon="file-invoice-dollar">
    Coverage, Claim
  </Accordion>
</AccordionGroup>

```bash theme={null}
pidgeon --output-format json capabilities --standard fhir
```

## NCPDP SCRIPT 2017071

<Warning>NCPDP SCRIPT generation is **closed by default** and license-gated. NCPDP's SCRIPT XSDs are member-only, so the standards material is not shipped: confirm your NCPDP membership, then run `pidgeon data install ncpdp-script --accept-license` to enable generation. Until the package is installed, NCPDP is reported as license-required.</Warning>

Once enabled, the SCRIPT transaction set spans the prescription workflow with XML serialization and structural validation:

<AccordionGroup>
  <Accordion title="Prescriptions" icon="prescription">
    NewRx, RxChangeRequest, RxChangeResponse, RefillRequest, RefillResponse, CancelRx, CancelRxResponse
  </Accordion>

  <Accordion title="Fills & History" icon="prescription-bottle">
    RxFill, RxHistoryRequest, RxHistoryResponse, ResupplyRequest, ResupplyResponse
  </Accordion>

  <Accordion title="Prior Authorization & Eligibility" icon="clipboard-check">
    PriorAuth, PriorAuthResponse, Predetermination, Eligibility, BenefitsCoordination
  </Accordion>

  <Accordion title="Formulary, Clinical & Infrastructure" icon="server">
    Formulary, DUR, DrugAlert, Interaction, Allergy, ClinicalInfo, Verify, Status, Error, Acknowledgment, and more
  </Accordion>
</AccordionGroup>

<Note>Run `pidgeon --output-format json capabilities --standard ncpdp` for the exact enabled set on your machine — it reports the license-required state until the `ncpdp-script` package is installed.</Note>

## Generation Modes

<AccordionGroup>
  <Accordion title="Procedural (Free)" icon="gear">
    Deterministic generation using reference datasets (ICD-10, LOINC, NDC, SNOMED). Fast and reproducible. Available to all users.

    ```bash theme={null}
    pidgeon generate ADT^A01 --mode procedural
    ```
  </Accordion>

  <Accordion title="Local AI (Pro)" icon="microchip">
    Uses a local AI model for enhanced clinical narratives and realistic note text.

    ```bash theme={null}
    pidgeon generate ORU^R01 --mode local-ai
    ```
  </Accordion>

  <Accordion title="API AI (Pro)" icon="cloud">
    Cloud AI provider for highest quality clinical narratives. Requires BYOK configuration.

    ```bash theme={null}
    pidgeon generate MDM^T02 --mode api-ai
    ```
  </Accordion>
</AccordionGroup>

## Reproducibility

Use `--seed` for deterministic output. The same seed always produces the same message, making tests repeatable across machines and CI runs:

```bash theme={null}
# Same seed = identical output every time
pidgeon generate ADT^A01 --seed 42

# With --count, every message uses the same seed (identical copies)
pidgeon generate ADT^A01 --count 10 --seed 42
```

## Vendor-Specific Generation

```bash theme={null}
pidgeon generate ADT^A01 --vendor epic_er --count 20
```

See [Vendor Profiles](/post/vendor-profiles) for creating and managing vendor configurations.

## Output Options

```bash theme={null}
# Write to a file
pidgeon generate ADT^A01 --output ./messages/admit.hl7

# JSON format for FHIR
pidgeon generate Patient --format json

# NDJSON for bulk loading
pidgeon generate Observation --count 100 --format ndjson
```