Course Teacher Assignments Assess

Assess student assignment submissions by accepting or rejecting them. Teachers can batch multiple decisions in a single transaction.

API Endpoint

POST /v2/tx/course/teacher/assignments/assess

Cost Summary

Cost Type	Amount	Notes
Transaction Fee	~0.27 ADA	Network fee
MinUTxO Refund	~-0.07 ADA	Datum shrinks on accept
Protocol Fee	0 ADA	No service fee
Total Wallet Delta	~0.21 ADA	Teacher may get small refund

The wallet delta is lower than the tx fee because the datum shrinks when an assignment is accepted (pending → completed), releasing some locked ADA.

Request Body

{
  "alias": "james",
  "course_id": "23a6bbce3a8deca8985764e847594f6956c9dc643e3f6c8efdba04e4",
  "assignment_decisions": [
    {
      "outcome": "accept",
      "alias": "student_001"
    }
  ]
}

Field	Type	Required	Description
`alias`	string	Yes	Teacher's access token alias
`course_id`	string	Yes	Course NFT policy ID (56 char hex)
`assignment_decisions`	object[]	Yes	List of assessment decisions
`assignment_decisions[].outcome`	string	Yes	"accept" or "refuse"
`assignment_decisions[].alias`	string	Yes	Student's alias

Transaction Pattern

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

┌─────────────────────────────────────────────────────────────────┐
│                ASSIGNMENTS ASSESS TRANSACTION                   │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  INPUTS                          OUTPUTS                        │
│  ──────                          ───────                        │
│  ┌─────────────────┐            ┌─────────────────┐            │
│  │ Course State    │───────────▶│ Course State    │            │
│  │ (student's      │  SPEND     │ (UPDATED:       │            │
│  │  pending)       │            │  completed)     │            │
│  └─────────────────┘            └─────────────────┘            │
│                                                                 │
│  ┌─────────────────┐            ┌─────────────────┐            │
│  │ Wallet          │───────────▶│ User Wallet     │            │
│  │ (u-token + ADA) │            │ (u-token +      │            │
│  └─────────────────┘            │  change)        │            │
│                                  └─────────────────┘            │
│  NO MINTING                                                     │
│                                                                 │
│  REFERENCE INPUTS                                               │
│  ────────────────                                               │
│  • global-state-v2 script ref                                   │
│  • LocalStateToken (course validator)                           │
│  • Governance UTxO (teacher verification)                       │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Inputs

Input	Type	Validator	Description
Course State	Script	course-state-validator	Student's pending assignment
Access Token	Wallet	-	Teacher's u-token
Wallet UTxOs	Wallet	-	ADA for fees

Outputs

Output	Validator	Value	Description
Course State	course-state-validator	~1.38 ADA + token	Updated: completed
User Wallet	wallet	u-token + change	Access token returned

Datum Changes

The course state datum changes when an assignment is accepted:

Before (Constructor 1 - active commitment):

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

After (Constructor 0 - no active commitment):

Constructor 0:
└── completed_modules: ["{slt_hash}"]

The slt_hash moves from the commitment fields to the completed_modules list.

Redeemers

Script	Constructor	Fields	Description
course-state-validator (spend)	2	teacher_alias	Assess action

{
  "constructor": 2,
  "fields": [
    { "bytes": "<teacher_alias>" }
  ]
}

Reference Inputs

UTxO	Description
Script Ref	global-state-v2 script reference
LocalStateToken	Course's LocalStateToken (validator script_ref)
Governance	Course governance UTxO (verifies teacher authorization)

Batching

Multiple assignment decisions can be batched in a single transaction:

{
  "assignment_decisions": [
    { "outcome": "accept", "alias": "student_001" },
    { "outcome": "accept", "alias": "student_002" },
    { "outcome": "refuse", "alias": "student_003" }
  ]
}

Key Notes

Teacher spends the student's course state UTxO
Authorization via teacher alias in redeemer + governance reference input
Datum shrinks on accept (drops assignment_info), reducing minUTxO
Completed SLT hashes accumulate in a list for credential claims
No protocol fee for assessments