Course Student Assignment Update

Update an existing assignment submission with new information while keeping the same SLT hash commitment.

API Endpoint

POST /v2/tx/course/student/assignment/update

Cost Summary

Cost Type	Amount	Notes
Transaction Fee	~0.27 ADA	Network fee
MinUTxO Delta	~0.06 ADA	If datum grows
Protocol Fee	0 ADA	No service fee
Total Wallet Delta	~0.33 ADA	May vary with datum size

The minUTxO increases when the datum grows (longer assignment_info string).

Request Body

{
  "alias": "student_001",
  "course_id": "e276a1f2729f06036299998f046765ffdde7ad8fd47f689690fbe2b1",
  "slt_hash": "10dde6f0936b3dba3339356838e59b1af0f511a777a8701c49d941351b3abcf0",
  "assignment_info": "updated assignment evidence hash"
}

Field	Type	Required	Description
`alias`	string	Yes	Student's access token alias
`course_id`	string	Yes	Course NFT policy ID (56 char hex)
`slt_hash`	string	Yes	Module token name (must match current commitment)
`assignment_info`	string	Yes	Updated evidence hash or description

Transaction Pattern

Spend and Recreate - No minting. Consumes and recreates course state UTxO with updated datum.

┌─────────────────────────────────────────────────────────────────┐
│                 ASSIGNMENT UPDATE TRANSACTION                   │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  INPUTS                          OUTPUTS                        │
│  ──────                          ───────                        │
│  ┌─────────────────┐            ┌─────────────────┐            │
│  │ Course State    │───────────▶│ Course State    │            │
│  │ (current        │  SPEND     │ (UPDATED        │            │
│  │  submission)    │            │  submission)    │            │
│  └─────────────────┘            └─────────────────┘            │
│                                                                 │
│  ┌─────────────────┐            ┌─────────────────┐            │
│  │ Wallet          │───────────▶│ User Wallet     │            │
│  │ (u-token + ADA) │            │ (u-token +      │            │
│  └─────────────────┘            │  change)        │            │
│                                  └─────────────────┘            │
│  NO MINTING                                                     │
│                                                                 │
│  REFERENCE INPUTS                                               │
│  ────────────────                                               │
│  • global-state-v2 script ref                                   │
│  • LocalStateToken (course validator)                           │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Inputs

Input	Type	Validator	Description
Course State	Script	course-state-validator	Student's course state (spent)
Access Token	Wallet	-	Student's u-token
Wallet UTxOs	Wallet	-	ADA for fees

Outputs

Output	Validator	Value	Description
Course State	course-state-validator	~1.50 ADA + token	Updated assignment info
User Wallet	wallet	u-token + change	Access token returned

Datum Changes

Only the assignment_info field changes - the SLT hash and completed_modules remain the same:

Before:

Constructor 1:
├── slt_hash: "{module_token_name}"
├── assignment_info: "original info"
└── completed_modules: []

After:

Constructor 1:
├── slt_hash: "{module_token_name}"
├── assignment_info: "updated assignment info"
└── completed_modules: []

Redeemers

Script	Constructor	Fields	Description
course-state-validator (spend)	1	slt_hash, assignment_info	Update action

{
  "constructor": 1,
  "fields": [
    { "bytes": "<slt_hash>" },
    { "bytes": "<new_assignment_info>" }
  ]
}

Note: The redeemer is a flat constructor 1 with two fields, NOT a nested structure.

Reference Inputs

UTxO	Description
Script Ref	global-state-v2 script reference
LocalStateToken	Course's LocalStateToken (validator script_ref)

Key Notes

SLT hash is unchanged between input and output
Datum stays as constructor 1 (active commitment state)
MinUTxO increases when assignment_info grows (student pays the difference)
No protocol fee for assignment updates
Student must own the course state token being updated