<?xml version='1.0' encoding='UTF-8'?>
<rfc xmlns:xi="http://www.w3.org/2001/XInclude" version="3" category="std" consensus="true" docName="draft-zhao-nmop-nma-nti-yang-00" ipr="trust200902" submissionType="IETF" tocInclude="true" sortRefs="true">
  <front>
    <title abbrev="NMA NTI YANG">Framework and YANG Data Model for the NMA Northbound Task Interface (NTI)</title>
    <seriesInfo name="Internet-Draft" value="draft-zhao-nmop-nma-nti-yang-00"/>
    <author fullname="Xing Zhao" initials="X." surname="Zhao">
      <organization abbrev="CAICT">China Academy of Information and Communication Technology</organization>
      <address>
        <postal>
          <country>China</country>
        </postal>
        <email>zhaoxing@caict.ac.cn</email>
      </address>
    </author>
	    <author fullname="Minxue Wang">
      <organization>China Mobile</organization>
      <address>
        <postal>
          <city>Beijing</city>
          <country>China</country>
        </postal>
        <email>wangminxue@chinamobile.com</email>
      </address>
    </author>
	<author fullname="Daniele Ceccarelli">
      <organization>Cisco</organization>
      <address>
        <email>dceccare@cisco.com</email>
      </address>
    </author>
    <author fullname="Yunbin Xu" initials="Y." surname="Xu"><organization abbrev="CAICT">China Academy of Information and Communications Technology</organization><address><postal><country>China</country></postal><email>xuyunbin@caict.ac.cn</email></address></author><date day="2" month="November" year="2026"/>
    <area>Operations and Management</area>
    <workgroup>Network Management Operations</workgroup>
    <keyword>NMA</keyword>
    <keyword>NTI</keyword>
    <keyword>YANG</keyword>
    <keyword>Network Management Agent</keyword>
    <abstract>
      <t>This document describes a framework and a YANG data model for the Northbound Task Interface (NTI) of a Network Management Agent (NMA). The NTI is a logical northbound interface through which upper-layer consumers, including OSS/BSS, orchestrators, management applications, and other agents, can submit network management tasks to an NMA and obtain task processing results.</t><t>This document specifies a YANG-based realization of the NTI, including operational state data, RPC operations, and notifications for capability discovery, intent submission, task lifecycle management, execution plan exposure, confirmation handling, and result reporting. The model is intended to reuse existing IETF network management models for domain-specific information.</t><t>The NTI does not mandate a dedicated communication protocol. NETCONF and RESTCONF can be used for the YANG-based realization, while A2A-based mechanisms may also be used to realize NTI interactions. This document does not define or extend generic agent interaction protocols.</t></abstract>
  </front>
  <middle>
    <section anchor="introduction">
      <name>Introduction</name>
      <t>Telecommunication networks are becoming increasingly complex in scale, technology composition, service diversity, and operational requirements. Traditional manual operation and fixed API-based management are often insufficient to support highly automated and adaptive network operations.</t>
      <t>As defined in <xref target="I-D.zhao-nmop-network-management-agent"/>, a Network Management Agent (NMA) is an autonomous network management entity with intent management, network context awareness, analysis, decision-making, and execution capabilities. It can interpret user goals, plan management actions, invoke tools and interfaces, monitor execution, and report results.</t>
      <t>To allow upper-layer consumers to invoke NMA capabilities in a structured and interoperable manner, the NMA architecture introduces the Northbound Task Interface (NTI). The NTI is a logical northbound task service interface that is independent of the type of consumer.</t>
      <t>The NTI interface supports:</t>
      <ul>
        <li>network management task capability discovery;</li>
        <li>natural-language or structured intent submission;</li>
        <li>task lifecycle monitoring;</li>
        <li>execution plan exposure;</li>
        <li>human-in-the-loop confirmation;</li>
        <li>task progress notification;</li>
        <li>consistent error reporting.</li>
      </ul>
      <t>OSS/BSS systems, orchestrators, management applications, and upper-layer agents or NMAs may consume NMA capabilities through the NTI. Existing A2A-based mechanisms, including telecommunications extensions such as TM Forum A2A-T <xref target="TMF-IG1453-A2A-T"/>, may also be used to realize NTI interactions. This document focuses on the YANG-based realization and does not duplicate generic agent communication mechanisms.</t>
      <t>The NTI YANG data model defines operational state data, RPC operations, and notifications for task-oriented network management. It does not define configuration datastore nodes for network resources and does not replace existing service, topology, alarm, incident, or performance management models. Task information can refer to domain-specific data defined by existing IETF YANG modules.</t>
      <t>The model is intended for use with existing YANG-based management protocols. This document does not define a separate transport protocol, a new HTTP resource API, or a separate notification delivery mechanism. Notification subscription and delivery reuse existing YANG notification mechanisms.</t>
    </section>
    <section anchor="terminology">
      <name>Terminology</name>
      <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 <xref target="RFC2119"/>
        <xref target="RFC8174"/> when, and only when, they appear in all capitals.</t>
		<t> The following terms are defined in this document:</t>
	  <dl newline="true" spacing="compact">
        <dt>Northbound Task Interface (NTI)</dt>
        <dd>A logical northbound interface through which upper-layer consumers submit network management tasks to an NMA and obtain task processing information and results.</dd>
        <dt>Network Management Agent (NMA)</dt>
        <dd>A network management entity defined in <xref target="I-D.zhao-nmop-network-management-agent"/> with autonomous task processing capabilities, which can interpret user goals, plan management actions, invoke tools and interfaces, monitor execution, and report results.</dd>
        <dt>NTI Consumer</dt>
        <dd>An upper-layer entity that consumes NMA capabilities through the NTI. Examples include OSS/BSS systems, orchestrators, management portals, automation systems, human-facing applications, and other agents or NMAs.</dd>
        <dt>Intent</dt>
        <dd>A goal description submitted to the NMA. It can be expressed using natural language or structured data.</dd>
        <dt>Task</dt>
        <dd>A management operation unit instantiated by the NMA for an accepted intent.</dd>
        <dt>Plan</dt>
        <dd>A sequence of steps generated by the NMA to execute a task.</dd>
        <dt>Confirmation</dt>
        <dd>A pending decision object generated when a task requires explicit approval, rejection, modification, or escalation.</dd>
        <dt>NTI Notification</dt>
        <dd>A YANG notification generated by the NMA to report task progress or state changes through the YANG-based NTI realization.</dd>
        <dt>A2A Interface</dt>
        <dd>An Agent-to-Agent interaction mechanism used between agents or NMAs. Non-agent applications may also act as A2A clients. Its protocol definition is outside the scope of this document.</dd>
      <dt>YANG-based NTI Realization</dt><dd>A realization of NTI task interactions using YANG operational state data, RPC operations, and notifications over existing YANG-based management protocols.</dd></dl>
    </section>
    <section anchor="scope">
      <name>Scope</name><t>This document specifies a YANG-based realization of the NMA Northbound Task Interface (NTI), including interface positioning, reference framework, information model, operational state data, RPC operations, and notifications. It also provides non-normative JSON examples illustrating NTI payloads and reuse of existing IETF domain models.</t><t>This document does not define a new transport protocol, a generic agent interaction protocol, a new HTTP resource API, or a new notification delivery mechanism. It does not replace existing network management information models, controller interfaces, or A2A-based interaction protocols. Detailed mappings to other agent interaction protocols, domain-specific service models, and internal NMA implementation mechanisms are outside the scope of this document.</t></section>
    <section anchor="nti-interface-positioning">
      <name>NTI Interface Positioning</name><t>The NTI is a logical northbound task service interface of an NMA. It enables upper-layer consumers to delegate network management tasks to an NMA and obtain information about task processing and outcomes.</t><t>The NTI is independent of the type of consumer and the communication protocol used. For example, an OSS/BSS system may access NMA task services using NETCONF or RESTCONF, while an upper-layer agent may use an A2A-based mechanism to invoke similar capabilities.</t><t>The NTI and A2A-based mechanisms, including TM Forum A2A-T <xref target="TMF-IG1453-A2A-T"/>, are not mutually exclusive. A2A-based mechanisms may realize NTI interactions, but may also support peer-agent collaboration outside the NTI. This document specifies the YANG-based realization and does not redefine generic agent task exchange or collaboration protocols.</t><t>The YANG-based NTI model is intended for integration with existing IETF network management systems and models. It describes task-related management information and operations, including intent submission, processing state, execution plans, confirmation handling, and result reporting. Domain-specific information may be carried using existing IETF management models.</t><t>A related NTI problem statement is discussed in <xref target="I-D.wu-nmop-nma-nti-problem-statement"/>.</t></section>
    <section anchor="nti-reference-framework">
      <name>NTI Reference Framework</name><t>The figure below illustrates the NTI as a logical task service that can be realized through different interaction mechanisms. This document specifies the YANG-based realization. The deployment relationship between the NMA and controllers is illustrative, and no separate transport or endpoint is mandated.</t><figure><name>Reference Framework of the NTI and Its Realization Mechanisms</name><artwork align="center" type="ascii-art"><![CDATA[+-----------------------------------------------------------------------+
|                   Upper-Layer Consumers                               |
|                                                                       |
| OSS/BSS | Orchestrator | Management Apps | Upper Agents / NMAs        |
+----------------------------------+------------------------------------+
                                   |
                         Logical NTI Task Service
                                   |
             +---------------------+---------------------+
             |                                           |
             v                                           v
+-------------------------------+        +------------------------------+
| YANG-based Realization        |        | A2A-based Realization        |
| (Scope of This Document)      |        | (Outside Scope)              |
|                               |        |                              |
| NETCONF / RESTCONF            |        | A2A / A2A-T mechanisms       |
| State / RPC / Notifications   |        | Agent/task interactions      |
+---------------+---------------+        +--------------+---------------+
                |                                       |
                +-------------------+-------------------+
                                    |
                                    v
+-----------------------------------------------------------------------+
|                   Network Management Agent (NMA)                      |
|                                                                       |
| Intent Management | Awareness | Analysis | Decision | Execution       |
+-----------------------------------+-----------------------------------+
                                    |
                         Existing Controller Functions
                                    |
                              Physical Network]]></artwork></figure><t>The YANG-based realization reuses existing management protocols and provides capability information, intent submission, task state access, confirmation resolution, notifications, and result reporting. A2A or A2A-T may provide an alternative interaction mechanism, but protocol bindings and mappings to the YANG model are not specified here.</t><t>A2A may also be used for inter-agent collaboration independently of the NTI. Thus, the logical task service does not imply that all A2A interactions are NTI interactions or that both realization mechanisms must be deployed.</t></section>
    <section anchor="nti-design-principles">
      <name>NTI Design Principles</name>
      <section anchor="protocol-binding-independence">
        <name>YANG-Based Management Protocol Reuse</name>
        <t>The NTI model is defined as a YANG module containing operational state data, RPC operations, and notifications. It is intended to be carried by existing YANG-based management protocols rather than by a dedicated new protocol.</t>
        <t>Protocol-specific details such as transport, URI layout, message framing, subscription establishment, and notification delivery are outside the scope of this document.</t>
      </section>
      <section anchor="unified-intent-entry">
        <name>Unified Intent Entry</name>
        <t>Natural-language and structured input share the same intent submission entry and the same task lifecycle. The mode field distinguishes the input type.</t>
      </section>
      <section anchor="unified-task-lifecycle">
        <name>Task State Representation</name>
        <t>After an intent is accepted, the NMA creates or associates a task. The task lifecycle includes:</t>
        <figure>
          <name>Lifecycle of a task</name>
          <artwork type="ascii-art"><![CDATA[PENDING -> ANALYZING -> PLANNING -> AWAITING_CONFIRMATION
        -> EXECUTING -> COMPLETED / FAILED / ABORTED]]></artwork>
        </figure>
        <t>Clarification may be requested when input is incomplete or ambiguous.</t>
      <t>These states represent task processing phases exposed by the YANG-based NTI realization. They do not replace or constrain task lifecycle representations used by other agent interaction protocols.</t></section>
      <section anchor="human-in-the-loop-confirmation">
        <name>Operational Confirmation and Authorization</name>
        <t>When a task violates a policy, affects critical resources, or requires human review, the NMA creates a confirmation object and suspends execution until the confirmation is resolved.</t>
      <t>Confirmation is distinct from authorization. Access to NTI operational data and RPC operations can be controlled using existing management access control mechanisms, such as NACM <xref target="RFC8341"/>. Authorization to invoke an NTI RPC does not automatically authorize subsequent network operations; relevant controller and network policies still apply.</t></section>
      <section anchor="yang-notification-reuse">
        <name>YANG Notification Reuse</name>
        <t>NTI task progress and state changes are reported using YANG notifications. This document defines the notification content in the NTI YANG module. Subscription, filtering, and delivery of NTI notifications are expected to use existing mechanisms such as Subscription to YANG Notifications <xref target="RFC8639"/>.</t>
        <t>Where an implementation supports subscription to operational datastore updates, YANG-Push <xref target="RFC8641"/> can also be used to observe changes to NTI operational state data such as task and confirmation state.</t>
      </section>
    </section>
    <section anchor="nti-information-model">
      <name>NTI Information Model</name>
      <t>The NTI information model contains five core components.</t>
      <section anchor="management-task-capabilities">
        <name>Management Task Capabilities</name>
        <t>The management-task-capabilities object describes network management
        task capabilities exposed by the NMA through the YANG-based NTI,
        including supported input schemas, confirmation requirements, and
        associated operational policies. The existing skills list represents
        the available task capabilities in this initial model.</t>
      <t>This management task capability information is scoped to the YANG-based NTI realization and is not intended to replace generic agent discovery mechanisms, such as A2A Agent Cards.</t></section>
      <section anchor="intent">
        <name>Intent</name>
        <t>The intent object represents a user or system goal.  Natural-language
        input includes the original user text.  Structured input includes the
        operation type, target resource, constraints, and priority.</t>
        <t>The intent-type identifies the high-level operation category.  It is
        not intended to encode all domain-specific subtypes.  Domain-specific
        details, such as service assurance objectives, fault symptoms, recovery
        constraints, or optimization policies, are carried in the constraints
        field.</t>
        <t>The constraints field of a structured intent is modeled as anydata,
        allowing it to carry domain-specific information objects defined by
        other IETF YANG modules.  For example, in fault handling and service
        assurance scenarios, the constraints MAY include incident information as
        defined in <xref target="I-D.ietf-nmop-network-incident-yang"/>, such
        as incident-id, incident-no, priority, category, sources,
        probable-causes, probable-events, and events, to provide the NMA with
        structured incident context for analysis and remediation.</t>
      </section>
      <section anchor="task">
        <name>Task</name>
        <t>The task object represents the lifecycle of an accepted intent.  It
        exposes task state, execution plan information, and task results.</t>
      </section>
      <section anchor="confirmation">
        <name>Confirmation</name>
        <t>The confirmation object represents a pending or resolved decision
        point.  It provides the context, allowed actions, status, and resolution
        information needed for human-in-the-loop or system-in-the-loop decision
        making.</t>
      </section>
      <section anchor="notification">
        <name>Notification</name>
        <t>NTI notifications report task progress and state changes.  The
        notification payload is modeled as a YANG choice so that different
        notification types can carry different payload structures.</t>
      </section>
    </section>
    <section anchor="yang-data-model">
      <name>YANG Data Model</name>
      <section anchor="model-design">
        <name>Model Design</name>
        <t>The model defined in this document (ietf-nma-nti) contains operational state data, RPC operations, and a YANG notification for the NTI interface. The operational state data expose NMA capabilities, submitted intents, tasks, and pending or resolved confirmations. RPC operations are used for intent submission, confirmation resolution, and task abort. The notification reports task progress and state changes.</t>
        <t>Domain-specific information can be carried using anydata fields with an associated schema identifier. For example, incident-related information can be aligned with <xref target="I-D.ietf-nmop-network-incident-yang"/> without redefining the incident model in this document.</t>
      </section>
      <section anchor="yang-tree">
        <name>YANG Tree</name>
        <t>The following tree provides a non-normative overview of the defined YANG model.</t>
        <figure>
          <name>YANG tree of ietf-nma-nti YANG model</name>
          <artwork type="ascii-art"><![CDATA[
module: ietf-nma-nti

  +--ro nti
     +--ro management-task-capabilities
     |  +--ro agent-id                    string
     |  +--ro version                     string
     |  +--ro skills* [skill-id]
     |  |  +--ro skill-id                 string
     |  |  +--ro name                     string
     |  |  +--ro description?             string
     |  |  +--ro input-schema?            union
     |  |  +--ro confirmation-required?   boolean
     |  |  +--ro tags*                    string
     |  +--ro policies
     |     +--ro human-in-the-loop?       boolean
     |     +--ro max-timeout-seconds?     uint32
     +--ro intent* [intent-id]
     |  +--ro intent-id                   string
     |  +--ro mode                        intent-mode
     |  +--ro submitter
     |  |  +--ro type?                    enumeration
     |  |  +--ro id?                      string
     |  +--ro timestamp?                  yang:date-and-time
     |  +--ro state?                      task-state
     |  +--ro task-id?                    string
     |  +--ro (mode-choice)
     |  |  +--:(natural-language)
     |  |  |  +--ro natural-language
     |  |  |     +--ro text               string
     |  |  +--:(structured)
     |  |     +--ro structured
     |  |        +--ro type               intent-type
     |  |        +--ro target-resource?   string
     |  |        +--ro constraints-schema? inet:uri
     |  |        +--ro constraints        anydata
     |  |        +--ro priority?          uint8
     |  +--ro estimated-completion?       uint32
     +--ro task* [task-id]
     |  +--ro task-id                     string
     |  +--ro parent-intent-id            string
     |  +--ro state                       task-state
     |  +--ro created-at                  yang:date-and-time
     |  +--ro updated-at                  yang:date-and-time
     |  +--ro plan* [step-id]
     |  |  +--ro step-id                  string
     |  |  +--ro action                   string
     |  |  +--ro target?                  string
     |  |  +--ro input-params?            anydata
     |  |  +--ro status                   step-state
     |  |  +--ro observation?             string
     |  |  +--ro started-at?              yang:date-and-time
     |  |  +--ro completed-at?            yang:date-and-time
     |  +--ro result
     |     +--ro summary?                 string
     |     +--ro affected-resources*      string
     |     +--ro output-data?             anydata
     +--ro confirmation* [confirmation-id]
        +--ro confirmation-id             string
        +--ro task-id                     string
        +--ro type                        confirmation-type
        +--ro priority?                   uint8
        +--ro timeout-seconds?            uint32
        +--ro context-schema?             inet:uri
        +--ro context                     anydata
        +--ro allowed-actions*            confirmation-action
        +--ro status?                     confirmation-status
        +--ro resolution
           +--ro action?                  confirmation-action
           +--ro modified-params-schema?  inet:uri
           +--ro modified-params?         anydata
           +--ro resolved-by?             string
           +--ro resolved-at?             yang:date-and-time

  rpcs:
    +---x submit-intent
    |  +---w input
    |  |  +---w request-id?           string
    |  |  +---w correlation-id?       string
    |  |  +---w tenant-id?            string
    |  |  +---w intent
    |  |     +---w uses intent-object
    |  +--ro output
    |     +--ro request-id?           string
    |     +--ro correlation-id?       string
    |     +--ro tenant-id?            string
    |     +--ro accepted              boolean
    |     +--ro intent-id?            string
    |     +--ro task-id?              string
    |     +--ro state?                task-state
    |     +--ro task
    |     |  +--ro uses task-object
    |     +--ro error
    |        +--ro uses error-info
    +---x resolve-confirmation
    |  +---w input
    |  |  +---w request-id?           string
    |  |  +---w correlation-id?       string
    |  |  +---w tenant-id?            string
    |  |  +---w confirmation-id       string
    |  |  +---w action                confirmation-action
    |  |  +---w modified-params-schema? inet:uri
    |  |  +---w modified-params?      anydata
    |  |  +---w resolved-by?          string
    |  +--ro output
    |     +--ro confirmation-id?      string
    |     +--ro task-id?              string
    |     +--ro status?               confirmation-status
    |     +--ro task-state?           task-state
    |     +--ro error
    |        +--ro uses error-info
    +---x abort-task
       +---w input
       |  +---w request-id?           string
       |  +---w correlation-id?       string
       |  +---w tenant-id?            string
       |  +---w task-id               string
       |  +---w reason?               string
       +--ro output
          +--ro task-id?              string
          +--ro state?                task-state
          +--ro error
             +--ro uses error-info

  notifications:
    +---n nti-task-notification
       +--ro task-id                  string
       +--ro intent-id?               string
       +--ro notification-type        nti-notification-type
       +--ro time?                    yang:date-and-time
       +--ro payload
          +--ro (notification-payload)
             +--:(plan-generated)
             +--:(confirmation-required)
             +--:(step-completed)
             +--:(step-failed)
             +--:(task-completed)
             +--:(task-failed)
]]></artwork>
        </figure>
      </section>
      <section anchor="yang-module">
        <name>YANG Module</name>
        <sourcecode type="yang" name="ietf-nma-nti@2026-11-02.yang"><![CDATA[module ietf-nma-nti {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-nma-nti";
  prefix nmanti;

  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Data Types";
  }

  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }

  organization
    "IETF NMOP Working Group";

  contact
    "WG Web:  <https://datatracker.ietf.org/wg/nmop/>
     WG List: <mailto:nmop@ietf.org>

     Editor:  Xing Zhao
              <mailto:zhaoxing@caict.ac.cn>";

  description
    "This module defines operational state data, RPC operations,
     and notifications for the Northbound Task Interface (NTI) of a
     Network Management Agent (NMA). This YANG-based realization is
     used by upper-layer consumers to invoke NMA task capabilities.";

  revision 2026-11-02 {
    description
      "Initial revision of the NTI YANG module.";
    reference
      "RFC XXXX: Framework and YANG Data Model for the NMA
       Northbound Task Interface (NTI).";
  }

  typedef intent-mode {
    type enumeration {
      enum natural-language {
        description "Intent expressed using natural language.";
      }
      enum structured {
        description "Intent expressed using structured data.";
      }
    }
    description
      "Intent input mode.";
  }

  typedef intent-type {
    type enumeration {
      enum CREATE {
        description
          "Create a service, resource, policy, or other managed object.";
      }
      enum DELETE {
        description
          "Delete a service, resource, policy, or other managed object.";
      }
      enum MODIFY {
        description
          "Modify an existing service, resource, policy, or other
           managed object.";
      }
      enum QUERY {
        description
          "Query status, state, inventory, performance, or other
           management information.";
      }
      enum REPORT {
        description
          "Generate a report based on network, service, or operational
           data.";
      }
      enum DIAGNOSE {
        description
          "Analyze symptoms, alarms, performance data, or events to
           identify possible root causes.";
      }
      enum REMEDIATE {
        description
          "Perform corrective or recovery actions for a detected fault,
           degradation, or abnormal condition.";
      }
      enum OPTIMIZE {
        description
          "Optimize service or network behavior according to performance,
           efficiency, cost, energy, capacity, or policy objectives.";
      }
      enum ASSURE {
        description
          "Assure a service, slice, resource, or policy objective by
           monitoring its state and taking or recommending actions when
           needed.";
      }
    }
    description
      "High-level structured intent operation category.  Domain-specific
       subtypes and constraints are carried in the constraints payload.";
  }

  typedef task-state {
    type enumeration {
      enum PENDING {
        description "Task has been created and is awaiting processing.";
      }
      enum ANALYZING {
        description "The NMA is analyzing the intent.";
      }
      enum AWAITING_CLARIFICATION {
        description "Additional information is required.";
      }
      enum PLANNING {
        description "The NMA is generating an execution plan.";
      }
      enum AWAITING_CONFIRMATION {
        description "The task is suspended until confirmation is resolved.";
      }
      enum EXECUTING {
        description "The NMA is executing the task.";
      }
      enum COMPLETED {
        description "The task has completed successfully.";
      }
      enum FAILED {
        description "The task has failed.";
      }
      enum ABORTED {
        description "The task has been aborted.";
      }
    }
    description
      "Task lifecycle state.";
  }

  typedef confirmation-type {
    type enumeration {
      enum EXECUTION {
        description "Confirmation before executing an action.";
      }
      enum PARAMETER_CHANGE {
        description "Confirmation of parameter changes.";
      }
      enum DESTRUCTIVE_OPERATION {
        description
          "Confirmation of a destructive or service-affecting operation.";
      }
      enum POLICY_VIOLATION {
        description
          "Confirmation of an action that violates or exceeds a policy.";
      }
    }
    description
      "Confirmation type.";
  }

  typedef nti-notification-type {
    type enumeration {
      enum plan-generated {
        description "An execution plan has been generated.";
      }
      enum confirmation-required {
        description "Confirmation is required.";
      }
      enum step-completed {
        description "A plan step has completed.";
      }
      enum step-failed {
        description "A plan step has failed.";
      }
      enum task-completed {
        description "The task has completed.";
      }
      enum task-failed {
        description "The task has failed.";
      }
    }
    description
      "Type of NTI task notification.";
  }

  typedef step-state {
    type enumeration {
      enum pending {
        description "Step is pending.";
      }
      enum running {
        description "Step is running.";
      }
      enum completed {
        description "Step has completed.";
      }
      enum failed {
        description "Step has failed.";
      }
      enum skipped {
        description "Step has been skipped.";
      }
    }
    description
      "Plan step state.";
  }

  typedef confirmation-action {
    type enumeration {
      enum approve {
        description "Approve the proposed action.";
      }
      enum reject {
        description "Reject the proposed action.";
      }
      enum modify-and-approve {
        description "Modify parameters and approve the action.";
      }
      enum escalate-to-human {
        description "Escalate the decision to a human operator.";
      }
    }
    description
      "Confirmation resolution action.";
  }

  typedef confirmation-status {
    type enumeration {
      enum pending {
        description "Confirmation is waiting for resolution.";
      }
      enum approved {
        description "Confirmation has been approved.";
      }
      enum rejected {
        description "Confirmation has been rejected.";
      }
      enum modified {
        description "Confirmation has been modified and approved.";
      }
      enum expired {
        description "Confirmation has expired.";
      }
      enum escalated {
        description "Confirmation has been escalated.";
      }
    }
    description
      "Confirmation status.";
  }

  typedef error-type {
    type enumeration {
      enum invalid-request {
        description "The request is invalid.";
      }
      enum unauthorized {
        description "Authentication is required or has failed.";
      }
      enum forbidden {
        description "The requester is not authorized.";
      }
      enum not-found {
        description "The requested object was not found.";
      }
      enum conflict {
        description "The request conflicts with the current state.";
      }
      enum unprocessable-content {
        description "The request cannot be processed semantically.";
      }
      enum internal-error {
        description "An internal error occurred.";
      }
    }
    description
      "NTI error type.";
  }

  grouping submitter-info {
    description
      "Information about the user, upper-layer system, or agent that
       submitted the request.";

    leaf type {
      type enumeration {
        enum user {
          description "Human user.";
        }
        enum system {
          description "Upper-layer software system, including agent applications.";
        }
      }
      description
        "Submitter type. The system value includes management
         applications and agent-based software clients.";
    }

    leaf id {
      type string;
      description
        "Submitter identifier.";
    }
  }

  grouping message-metadata {
    description
      "Common metadata used for request correlation and tenancy context.";

    leaf request-id {
      type string;
      description
        "Identifier of the request.";
    }

    leaf correlation-id {
      type string;
      description
        "Identifier used to correlate related NTI interactions.";
    }

    leaf tenant-id {
      type string;
      description
        "Identifier of the tenant, customer, organization, project,
         administrative domain, or other management context associated
         with the request.";
    }
  }

  grouping error-info {
    description
      "Common error information returned by the NTI interface.";

    leaf error-type {
      type error-type;
      description "Error type.";
    }

    leaf error-code {
      type string;
      description "Machine-readable error code.";
    }

    leaf error-message {
      type string;
      description "Human-readable error message.";
    }

    leaf retryable {
      type boolean;
      default "false";
      description "Whether retry may succeed.";
    }

    leaf target {
      type string;
      description "Target object or field related to the error.";
    }

    anydata details {
      description "Additional error details.";
    }
  }

  grouping management-task-capabilities-object {
    description
      "Network management task capabilities exposed through the NTI.";

    leaf agent-id {
      type string;
      mandatory true;
      description "NMA identifier.";
    }

    leaf version {
      type string;
      mandatory true;
      description "NMA version.";
    }

    list skills {
      key "skill-id";
      description "Network management task capabilities exposed by the NMA.";

      leaf skill-id {
        type string;
        description "Skill identifier.";
      }

      leaf name {
        type string;
        mandatory true;
        description "Human-readable skill name.";
      }

      leaf description {
        type string;
        description "Skill description.";
      }

      leaf input-schema {
        type union {
          type inet:uri;
          type string;
        }
        description
          "Input schema URI or inline schema description.";
      }

      leaf confirmation-required {
        type boolean;
        default "false";
        description
          "Whether this skill normally requires confirmation before
           execution.";
      }

      leaf-list tags {
        type string;
        description
          "Optional tags used to classify or discover this skill.";
      }
    }

    container policies {
      description "Global policies advertised by the NMA.";

      leaf human-in-the-loop {
        type boolean;
        default "true";
        description "Whether human-in-the-loop is enabled by default.";
      }

      leaf max-timeout-seconds {
        type uint32;
        units "seconds";
        description "Maximum timeout in seconds.";
      }
    }
  }

  grouping intent-object {
    description
      "Intent submitted to the NMA.";

    leaf intent-id {
      type string;
      description "Intent identifier.";
    }

    leaf mode {
      type intent-mode;
      mandatory true;
      description "Intent input mode.";
    }

    container submitter {
      description "Submitter information.";
      uses submitter-info;
    }

    leaf timestamp {
      type yang:date-and-time;
      description "Submission timestamp.";
    }

    leaf state {
      type task-state;
      description "Current processing state associated with this intent.";
    }

    leaf task-id {
      type string;
      description "Associated task identifier.";
    }

    choice mode-choice {
      description "Mode-specific intent content.";

      case natural-language {
        container natural-language {
          description "Natural-language input.";

          leaf text {
            type string;
            mandatory true;
            description
              "Natural-language text submitted by the user or system.";
          }
        }
      }

      case structured {
        container structured {
          description "Structured input.";

          leaf type {
            type intent-type;
            mandatory true;
            description "High-level operation category.";
          }

          leaf target-resource {
            type string;
            description "Target service, resource, slice, domain, or object.";
          }

          leaf constraints-schema {
            type inet:uri;
            description "Schema used to interpret constraints.";
          }

          anydata constraints {
            mandatory true;
            description
              "Domain-specific constraints. This field MAY carry
               information objects defined by other IETF YANG modules.
               For example, in fault handling scenarios, incident
               information as defined in the ietf-incident module MAY
               be included.";
          }

          leaf priority {
            type uint8 {
              range "1..10";
            }
            default "5";
            description "Intent priority.";
          }
        }
      }
    }

    leaf estimated-completion {
      type uint32;
      units "seconds";
      description "Estimated completion time.";
    }
  }

  grouping plan-step {
    description
      "A step in a task execution plan.";

    leaf step-id {
      type string;
      description "Step identifier.";
    }

    leaf action {
      type string;
      mandatory true;
      description "Action to be performed.";
    }

    leaf target {
      type string;
      description "Target of the action.";
    }

    anydata input-params {
      description "Step input parameters.";
    }

    leaf status {
      type step-state;
      mandatory true;
      description "Step status.";
    }

    leaf observation {
      type string;
      description "Observation or result generated by this step.";
    }

    leaf started-at {
      type yang:date-and-time;
      description "Step start time.";
    }

    leaf completed-at {
      type yang:date-and-time;
      description "Step completion time.";
    }
  }

  grouping task-object {
    description
      "Task lifecycle information.";

    leaf task-id {
      type string;
      description "Task identifier.";
    }

    leaf parent-intent-id {
      type string;
      mandatory true;
      description "Identifier of the parent intent.";
    }

    leaf state {
      type task-state;
      mandatory true;
      description "Current task state.";
    }

    leaf created-at {
      type yang:date-and-time;
      mandatory true;
      description "Task creation time.";
    }

    leaf updated-at {
      type yang:date-and-time;
      mandatory true;
      description "Last task update time.";
    }

    list plan {
      key "step-id";
      description "Execution plan.";
      uses plan-step;
    }

    container result {
      description "Task result or intermediate output.";

      leaf summary {
        type string;
        description "Result summary.";
      }

      leaf-list affected-resources {
        type string;
        description "Resources affected by the task.";
      }

      anydata output-data {
        description "Structured output data.";
      }
    }
  }

  grouping confirmation-object {
    description
      "Confirmation information used for human-in-the-loop or
       system-in-the-loop decision making.";

    leaf confirmation-id {
      type string;
      description "Confirmation identifier.";
    }

    leaf task-id {
      type string;
      mandatory true;
      description "Associated task identifier.";
    }

    leaf type {
      type confirmation-type;
      mandatory true;
      description "Confirmation type.";
    }

    leaf priority {
      type uint8 {
        range "1..10";
      }
      default "5";
      description "Confirmation priority.";
    }

    leaf timeout-seconds {
      type uint32;
      default "300";
      units "seconds";
      description "Timeout for resolving the confirmation.";
    }

    leaf context-schema {
      type inet:uri;
      description "Schema used to interpret context.";
    }

    anydata context {
      mandatory true;
      description "Context needed to resolve the confirmation.";
    }

    leaf-list allowed-actions {
      type confirmation-action;
      min-elements 1;
      description "Actions allowed for this confirmation.";
    }

    leaf status {
      type confirmation-status;
      default "pending";
      description "Confirmation status.";
    }

    container resolution {
      description "Final resolution of the confirmation.";

      leaf action {
        type confirmation-action;
        description "Selected resolution action.";
      }

      leaf modified-params-schema {
        type inet:uri;
        description "Schema used to interpret modified-params.";
      }

      anydata modified-params {
        description "Modified parameters.";
      }

      leaf resolved-by {
        type string;
        description "Resolver identifier.";
      }

      leaf resolved-at {
        type yang:date-and-time;
        description "Resolution time.";
      }
    }
  }

  container nti {
    config false;
    description
      "Operational state data for the NTI interface.";

    container management-task-capabilities {
      description
        "Network management task capabilities exposed through NTI.";
      uses management-task-capabilities-object;
    }

    list intent {
      key "intent-id";
      description
        "Intents submitted through NTI and retained as operational
         state for tracking.";
      uses intent-object;
    }

    list task {
      key "task-id";
      description
        "Tasks created or associated with accepted intents.";
      uses task-object;
    }

    list confirmation {
      key "confirmation-id";
      description
        "Confirmation objects generated by the NMA.";
      uses confirmation-object;
    }
  }

  rpc submit-intent {
    description
      "Submit an intent to the NMA.";
    input {
      uses message-metadata;
      container intent {
        description "Submitted intent.";
        uses intent-object;
      }
    }
    output {
      uses message-metadata;
      leaf accepted {
        type boolean;
        mandatory true;
        description "Whether the intent was accepted.";
      }
      leaf intent-id {
        type string;
        description "Accepted intent identifier.";
      }
      leaf task-id {
        type string;
        description "Created or associated task identifier.";
      }
      leaf state {
        type task-state;
        description "Current task state.";
      }
      container task {
        description "Task information when available.";
        uses task-object;
      }
      container error {
        description "Error information.";
        uses error-info;
      }
    }
  }

  rpc resolve-confirmation {
    description
      "Resolve a pending confirmation.";
    input {
      uses message-metadata;
      leaf confirmation-id {
        type string;
        mandatory true;
        description "Confirmation identifier.";
      }
      leaf action {
        type confirmation-action;
        mandatory true;
        description "Selected resolution action.";
      }
      leaf modified-params-schema {
        type inet:uri;
        description "Schema used to interpret modified-params.";
      }
      anydata modified-params {
        description "Modified parameters.";
      }
      leaf resolved-by {
        type string;
        description "Resolver identifier.";
      }
    }
    output {
      leaf confirmation-id {
        type string;
        description "Confirmation identifier.";
      }
      leaf task-id {
        type string;
        description "Associated task identifier.";
      }
      leaf status {
        type confirmation-status;
        description "Updated confirmation status.";
      }
      leaf task-state {
        type task-state;
        description "Updated task state.";
      }
      container error {
        description "Error information.";
        uses error-info;
      }
    }
  }

  rpc abort-task {
    description
      "Abort an NTI task.";
    input {
      uses message-metadata;
      leaf task-id {
        type string;
        mandatory true;
        description "Task identifier.";
      }
      leaf reason {
        type string;
        description "Reason for aborting the task.";
      }
    }
    output {
      leaf task-id {
        type string;
        description "Task identifier.";
      }
      leaf state {
        type task-state;
        description "Updated task state.";
      }
      container error {
        description "Error information.";
        uses error-info;
      }
    }
  }

  notification nti-task-notification {
    description
      "Notification generated when an NTI task changes state or
       produces progress information.";

    leaf task-id {
      type string;
      mandatory true;
      description "Associated task identifier.";
    }

    leaf intent-id {
      type string;
      description "Associated intent identifier.";
    }

    leaf notification-type {
      type nti-notification-type;
      mandatory true;
      description "NTI notification type.";
    }

    leaf time {
      type yang:date-and-time;
      description "Time when the notification was generated.";
    }

    container payload {
      description "Notification-type-specific payload.";

      choice notification-payload {
        description "Payload selected according to notification type.";

        case plan-generated {
          container plan-generated {
            leaf step-count {
              type uint32;
              mandatory true;
              description "Number of generated plan steps.";
            }
            leaf estimated-duration {
              type uint32;
              units "seconds";
              description "Estimated execution duration.";
            }
          }
        }

        case confirmation-required {
          container confirmation-required {
            description
              "Payload carried when a task requires confirmation.  The
               payload provides a summary of the confirmation so that
               the client can present the decision request without
               necessarily retrieving the full confirmation object.";

            leaf confirmation-id {
              type string;
              mandatory true;
              description
                "Identifier of the confirmation object created by the
                 NMA.  The full confirmation object can be read from
                 NTI operational state data using this identifier.";
            }

            leaf confirmation-type {
              type confirmation-type;
              description
                "Type of confirmation required.";
            }

            leaf priority {
              type uint8 {
                range "1..10";
              }
              description
                "Priority of the confirmation.";
            }

            leaf timeout-seconds {
              type uint32;
              units "seconds";
              description
                "Timeout for resolving the confirmation.";
            }

            leaf context-schema {
              type inet:uri;
              description
                "Schema used to interpret the confirmation context.";
            }

            leaf summary {
              type string;
              description
                "Human-readable summary of the confirmation request.";
            }

            leaf-list allowed-actions {
              type confirmation-action;
              description
                "Actions allowed for this confirmation.";
            }
          }
        }

        case step-completed {
          container step-completed {
            leaf step-id {
              type string;
              mandatory true;
              description "Completed step identifier.";
            }
            leaf observation {
              type string;
              description "Step observation.";
            }
          }
        }

        case step-failed {
          container step-failed {
            leaf step-id {
              type string;
              mandatory true;
              description "Failed step identifier.";
            }
            leaf exception-type {
              type string;
              mandatory true;
              description "Exception type.";
            }
            leaf affected-scope {
              type string;
              description "Affected scope.";
            }
            leaf-list remedial-suggestions {
              type string;
              description "Suggested remedial actions.";
            }
          }
        }

        case task-completed {
          container task-completed {
            leaf summary {
              type string;
              mandatory true;
              description "Task completion summary.";
            }
            leaf-list affected-resources {
              type string;
              description "Affected resources.";
            }
          }
        }

        case task-failed {
          container task-failed {
            leaf reason {
              type string;
              mandatory true;
              description "Task failure reason.";
            }
            leaf failed-step-id {
              type string;
              description "Failed step identifier.";
            }
          }
        }
      }
    }
  }
}
]]></sourcecode>
      </section>
    </section>
    <section anchor="security-considerations">
      <name>Security Considerations</name>
      <t>The NTI YANG module can expose sensitive operational information, including intents, tasks, plans, affected resources, confirmation context, notifications, and results.</t>
      <t>The YANG module specified in this document is designed to be accessed via YANG-based management protocols, such as NETCONF <xref target="RFC6241"/> and RESTCONF <xref target="RFC8040"/>. Implementations are expected to provide secure transport, mutual authentication, authorization, confidentiality protection, integrity protection, replay protection, audit logging, and policy enforcement.</t>
      <t>RPC operations such as submit-intent, resolve-confirmation, and abort-task can affect network operations indirectly through the NMA. Access to these RPC operations needs to be restricted to authorized clients.</t>
      <t>Natural-language inputs and AI-assisted interpretation may introduce risks such as ambiguous instructions, malicious input, prompt injection, or incorrect interpretation. Implementations should validate interpreted results before execution and should use confirmation or policy checks for risky operations.</t>
      <t>Confirmation resolution operations can affect network behavior and therefore require authorization and audit logging.</t>
      <t>NTI notifications may contain sensitive operational information. Implementations should ensure that notification subscribers are authorized to receive the corresponding notifications.</t>
      <t>Future versions of this document are expected to expand this section.</t>
    <t>Access to NTI operational state, RPC operations, and notifications should be controlled by suitable management access control mechanisms, including NACM <xref target="RFC8341"/>, where applicable. Authorization for downstream operations remains subject to the applicable controller policies and network access controls. Task and confirmation details can expose sensitive information about affected network resources.</t></section>
    <section anchor="iana-considerations">
      <name>IANA Considerations</name>
      <t>This version of the document does not request any IANA actions.</t>
      <t>Future versions may request registration of the YANG module namespace and module name if the YANG module becomes normative.</t>
      <t>Expected future namespace:</t>
      <sourcecode><![CDATA[urn:ietf:params:xml:ns:yang:ietf-nma-nti]]></sourcecode>
      <t>Expected future module name:</t>
      <sourcecode><![CDATA[ietf-nma-nti]]></sourcecode>
    </section>
  </middle>
  <back>
  <references>
	<name>References</name>
	<references>
      <name>Normative References</name>
      <reference target="https://www.rfc-editor.org/rfc/rfc2119" anchor="RFC2119">
        <front>
          <title>Key words for use in RFCs to Indicate Requirement Levels</title>
          <author initials="S." surname="Bradner" fullname="Scott Bradner"/>
          <date month="March" year="1997"/>
        </front>
        <seriesInfo name="RFC" value="2119"/>
      </reference>
      <reference target="https://www.rfc-editor.org/rfc/rfc8174" anchor="RFC8174">
        <front>
          <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
          <author initials="B." surname="Leiba" fullname="Barry Leiba"/>
          <date month="May" year="2017"/>
        </front>
        <seriesInfo name="RFC" value="8174"/>
      </reference>
      <reference anchor="RFC6991" target="https://www.rfc-editor.org/rfc/rfc6991">
        <front>
          <title>Common YANG Data Types</title>
          <author initials="J." surname="Schoenwaelder" fullname="Juergen Schoenwaelder"/>
          <date month="July" year="2013"/>
        </front>
        <seriesInfo name="RFC" value="6991"/>
      </reference>
      <reference anchor="RFC7950" target="https://www.rfc-editor.org/rfc/rfc7950">
        <front>
          <title>The YANG 1.1 Data Modeling Language</title>
          <author initials="M." surname="Bjorklund" fullname="Martin Bjorklund"/>
          <date month="August" year="2016"/>
        </front>
        <seriesInfo name="RFC" value="7950"/>
      </reference>
    </references>
    <references>
      <name>Informative References</name>
      <reference anchor="RFC8639" target="https://www.rfc-editor.org/rfc/rfc8639">
        <front>
          <title>Subscription to YANG Notifications</title>
          <author initials="E." surname="Voit" fullname="Eric Voit"/>
          <date month="September" year="2019"/>
        </front>
        <seriesInfo name="RFC" value="8639"/>
      </reference>
      <reference anchor="I-D.zhao-nmop-network-management-agent" target="https://datatracker.ietf.org/doc/draft-zhao-nmop-network-management-agent/">
        <front>
          <title>AI based Network Management Agent (NMA): Concepts and Architecture</title>
          <author initials="X." surname="Zhao" fullname="Xing Zhao"/>
          <date month="February" year="2026"/>
        </front>
        <seriesInfo name="Internet-Draft" value="draft-zhao-nmop-network-management-agent"/>
      </reference>
      <reference anchor="RFC6241" target="https://www.rfc-editor.org/rfc/rfc6241">
        <front>
          <title>Network Configuration Protocol (NETCONF)</title>
          <author initials="R." surname="Enns" fullname="Rob Enns"/>
          <author initials="M." surname="Bjorklund" fullname="Martin Bjorklund"/>
          <author initials="J." surname="Schoenwaelder" fullname="Juergen Schoenwaelder"/>
          <author initials="A." surname="Bierman" fullname="Andy Bierman"/>
          <date month="June" year="2011"/>
        </front>
        <seriesInfo name="RFC" value="6241"/>
      </reference>
      <reference anchor="RFC8040" target="https://www.rfc-editor.org/rfc/rfc8040">
        <front>
          <title>RESTCONF Protocol</title>
          <author initials="A." surname="Bierman" fullname="Andy Bierman"/>
          <author initials="M." surname="Bjorklund" fullname="Martin Bjorklund"/>
          <author initials="K." surname="Watsen" fullname="Kent Watsen"/>
          <date month="January" year="2017"/>
        </front>
        <seriesInfo name="RFC" value="8040"/>
      </reference>
      <reference anchor="RFC8641" target="https://www.rfc-editor.org/rfc/rfc8641">
        <front>
          <title>Subscription to YANG Notifications for Datastore Updates</title>
          <author initials="E." surname="Voit" fullname="Eric Voit"/>
          <author initials="A." surname="Clemm" fullname="Alexander Clemm"/>
          <author initials="A." surname="Gonzalez Prieto" fullname="Alexander Gonzalez Prieto"/>
          <author initials="E." surname="Nilsen-Nygaard" fullname="Eric Nilsen-Nygaard"/>
          <author initials="A." surname="Tripathy" fullname="Ambika Tripathy"/>
          <date month="September" year="2019"/>
        </front>
        <seriesInfo name="RFC" value="8641"/>
      </reference>
      <reference anchor="I-D.ietf-nmop-network-incident-yang" target="https://datatracker.ietf.org/doc/draft-ietf-nmop-network-incident-yang/">
        <front>
          <title>A YANG Data Model for Network Incident Management</title>
          <author initials="T." surname="Hu" fullname="Tong Hu"/>
          <author initials="L. M." surname="Contreras" fullname="Luis M. Contreras"/>
          <author initials="Q." surname="Wu" fullname="Qin Wu"/>
          <author initials="N." surname="Davis" fullname="Nigel Davis"/>
          <author initials="C." surname="Feng" fullname="Chong Feng"/>
          <date day="29" month="June" year="2026"/>
        </front>
        <seriesInfo name="Internet-Draft" value="draft-ietf-nmop-network-incident-yang-09"/>
        <refcontent>Work in Progress</refcontent>
      </reference>
    <reference anchor="I-D.wu-nmop-nma-nti-problem-statement" target="https://datatracker.ietf.org/doc/draft-wu-nmop-nma-nti-problem-statement/"><front><title>Problem Statement for Standardizing the northbound Task Interface (NTI) of the Network Management Agent</title><author fullname="Bo Wu"/><author fullname="Minxue Wang"/><author fullname="Xing Zhao"/><author fullname="Daniele Ceccarelli"/><author fullname="Haomian Zheng"/><author fullname="Jin Zhou"/><date month="July" year="2026"/></front><seriesInfo name="Internet-Draft" value="draft-wu-nmop-nma-nti-problem-statement-00"/></reference><reference anchor="TMF-IG1453-A2A-T" target="https://www.tmforum.org/resources/introductory-guide/ig1453-agent-to-agent-protocol-for-telecoms-v2-1-0/"><front><title>Agent to Agent Protocol for Telecoms, Version 2.1.0</title><author fullname="TM Forum"/><date month="June" year="2026"/></front><seriesInfo name="TM Forum" value="IG1453 v2.1.0"/></reference><reference anchor="RFC8341" target="https://www.rfc-editor.org/rfc/rfc8341"><front><title>Network Configuration Access Control Model</title><author fullname="Andy Bierman"/><author fullname="Martin Bjorklund"/><date month="March" year="2018"/></front><seriesInfo name="RFC" value="8341"/></reference></references>
</references>
    <section anchor="appendix-nti-yang-protocol-interaction">
      <name>Example NTI Interaction Using YANG-Based Management Protocols</name>
      <t>This appendix provides a non-normative example of an NTI interaction flow in a network incident diagnosis scenario. RESTCONF-style resource paths are used only to illustrate how NTI operational state data, RPC operations, and YANG notifications can be accessed by an NTI consumer.</t>
      <t>A typical NTI interaction can proceed as follows:</t>
      <ul>
        <li>The NTI consumer first discovers the exposed management task capabilities.</li>
        <li>The NTI consumer invokes the submit-intent RPC with either natural-language input or structured input.</li>
        <li>The NMA creates or updates intent and task operational state.</li>
        <li>The NTI consumer observes task state by subscribing to NTI task notifications.</li>
        <li>When confirmation is required, the NMA creates a confirmation object and sends a confirmation-required notification.</li>
        <li>The NTI consumer invokes the resolve-confirmation RPC to approve, reject, modify, or escalate the proposed action.</li>
        <li>The NMA continues execution and sends task progress or completion notifications.</li>
      </ul>
      <figure>
        <name>Example NTI Interaction Flow Using a YANG-Based Management Protocol</name>
        <artwork type="ascii-art"><![CDATA[
+--------------+                                               +------------+
| NTI Consumer |                                               | NMA        |
|   (Client)   |                                               |  (Server)  |
+-------+------+                                               +-------+----+
        |                                                              |
        | 1. GET /restconf/data/ietf-nma-nti:nti/                     |
        |    management-task-capabilities                               |
        |------------------------------------------------------------->|
        |                                                              |
        | 2. Return management task capabilities                       |
        |<-------------------------------------------------------------|
        |                                                              |
        | 3. POST /restconf/operations/ietf-nma-nti:submit-intent      |
        |    Input: incident diagnosis intent with                     |
        |    ietf-incident aligned constraints                         |
        |------------------------------------------------------------->|
        |                                                              |
        | 4. Return accepted result: intent-id, task-id, state         |
        |<-------------------------------------------------------------|
        |                                                              |
        | 5. Establish subscription for nti-task-notification          |
        |------------------------------------------------------------->|
        |                                                              |
        | 6. Subscription established                                  |
        |<-------------------------------------------------------------|
        |                                                              |
        | 7. Notification: plan-generated                              |
        |<-------------------------------------------------------------|
        |                                                              |
        | 8. Notification: confirmation-required                       |
        |    Carries confirmation-id and compact summary               |
        |<-------------------------------------------------------------|
        |                                                              |
        | 9. Optional: GET /restconf/data/ietf-nma-nti:nti/            |
        |    confirmation=confirmation-id                              |
        |------------------------------------------------------------->|
        |                                                              |
        |10. Return confirmation object: context, actions, status      |
        |<-------------------------------------------------------------|
        |                                                              |
        |11.POST /restconf/operations/ietf-nma-nti:resolve-confirmation|
        |    Input: confirmation-id, action, resolved-by,              |
        |    optional modified-params                                  |
        |------------------------------------------------------------->|
        |                                                              |
        |12. Return confirmation result and updated task-state         |
        |<-------------------------------------------------------------|
        |                                                              |
        |13. Notification: step-completed                              |
        |<-------------------------------------------------------------|
        |                                                              |
        |14. Notification: task-completed                              |
        |<-------------------------------------------------------------|
        |                                                              |
        |15.Optional: GET /restconf/data/ietf-nma-nti:nti/task=task-id |
        |------------------------------------------------------------->|
        |                                                              |
        |16. Return final task state and result                        |
        |<-------------------------------------------------------------|
        |                                                              |
+-------+------+                                               +-------+----+
| NTI Consumer |                                               | NMA        |
|   (Client)   |                                               |  (Server)  |
+--------------+                                               +------------+
]]></artwork>
      </figure>
    </section>
    <section anchor="appendix-json-examples">
      <name>JSON Examples</name>
      <t>This appendix provides non-normative JSON examples for an OTN network incident diagnosis and resolution scenario. The examples demonstrate how the NTI interface can carry incident-related information aligned with the ietf-incident module defined in <xref target="I-D.ietf-nmop-network-incident-yang"/>. In this example, the NTI model does not redefine the incident model. Instead, the NTI envelope carries the user-facing interaction semantics, such as intent submission, task lifecycle, confirmation, and notification, while the constraints and confirmation context reuse incident fields such as incident-no, service-instance, domain, priority, status, sources, probable-causes, probable-events, and events.</t>
      <t>In this example, a vendor's OSS detects degradation of an OTN service and invokes the NMA through NTI by submitting an incident diagnosis intent. The structured intent carries incident information aligned with <xref target="I-D.ietf-nmop-network-incident-yang"/>. After accepting the intent, the NMA perceives the incident, analyzes the probable root cause, generates an incident resolution plan, and creates a confirmation object before executing a service-affecting recovery action. Task progress and state changes are reported using NTI YANG notifications.</t>
	  <t>Examples of NTI interface message contents are provided below in sequence from intent initiation, task planning, confirmation, execution to feedback.</t>
      <section anchor="appendix-management-task-capabilities">
        <name>Management Task Capabilities</name>
        <sourcecode type="json"><![CDATA[{
  "agent-id": "nma-transport-1",
  "version": "0.1.0",
  "skills": [
    {
      "skill-id": "otn-incident-handling",
      "name": "OTN incident handling",
      "description": "Analyze OTN alarms, performance degradation, and service impact, and propose or execute recovery actions.",
      "input-schema": "urn:ietf:params:xml:ns:yang:ietf-incident",
      "confirmation-required": true,
      "tags": [
        "transport",
        "otn",
        "incident",
        "remediation"
      ]
    }
  ],
  "policies": {
    "human-in-the-loop": true,
    "max-timeout-seconds": 1800
  }
}]]></sourcecode>
      </section>
      
 <section anchor="appendix-intent-submission-rpc">
  <name>Intent Submission RPC</name>
  <t>The following examples show the input and output of the
  submit-intent RPC.  The RPC can carry either a natural-language intent
  or a structured intent.  Both input modes use the same submit-intent RPC
  and follow the same task lifecycle after the intent is accepted.</t>

  <t>Input example using a natural-language intent:</t>
  <sourcecode type="json"><![CDATA[{
  "request-id": "req-1001",
  "correlation-id": "corr-20260630-001",
  "tenant-id": "tenant-1",
  "intent": {
    "intent-id": "intent-1001",
    "mode": "natural-language",
    "submitter": {
      "type": "system",
      "id": "oss-a"
    },
    "timestamp": "2026-06-30T10:00:00Z",
    "natural-language": {
      "text": "Analyze the service degradation of OTN service svc-1001, identify the root cause, assess affected resources, and recommend recovery actions."
    }
  }
}]]></sourcecode>

  <t>Input example using a structured intent:</t>
  <sourcecode type="json"><![CDATA[{
  "request-id": "req-1002",
  "correlation-id": "corr-20260630-002",
  "tenant-id": "tenant-1",
  "intent": {
    "intent-id": "intent-1002",
    "mode": "structured",
    "submitter": {
      "type": "system",
      "id": "orchestrator-a"
    },
    "timestamp": "2026-06-30T10:05:00Z",
    "structured": {
      "type": "DIAGNOSE",
      "target-resource": "incident-56433218",
      "constraints-schema": "urn:ietf:params:xml:ns:yang:ietf-incident",
      "constraints": {
        "incident-no": 56433218,
        "name": "otn-service-degradation",
        "type": "problem",
        "incident-id": "line-fault-svc-1001",
        "service-instance": [
          "svc-1001"
        ],
        "domain": "otn",
        "priority": "critical",
        "status": "raised",
        "ack-status": "unacknowledged",
        "category": "network",
        "detail": "OTN service svc-1001 is degraded. OTU_LOF and ODU_AIS alarm events were observed on the working path.",
        "resolve-advice": "Diagnose the probable root cause and provide recovery suggestions. Prefer actions that minimize impact on running services.",
        "occur-time": "2026-06-30T09:59:30Z",
        "raise-time": "2026-06-30T10:00:00Z",
        "last-updated": "2026-06-30T10:05:00Z"
      },
      "priority": 9
    }
  }
}]]></sourcecode>

  <t>Output example after the intent is accepted:</t>
  <sourcecode type="json"><![CDATA[{
  "request-id": "req-1002",
  "correlation-id": "corr-20260630-002",
  "tenant-id": "tenant-1",
  "accepted": true,
  "intent-id": "intent-1002",
  "task-id": "task-2001",
  "state": "PENDING"
}]]></sourcecode>
</section>
	  
	  
      <section anchor="appendix-task-object">
        <name>Task Object</name>
        <sourcecode type="json"><![CDATA[{
  "task-id": "task-2001",
  "parent-intent-id": "intent-1002",
  "state": "AWAITING_CONFIRMATION",
  "created-at": "2026-06-30T10:00:00Z",
  "updated-at": "2026-06-30T10:03:30Z",
  "plan": [
    {
      "step-id": "step-1",
      "action": "perceive-network-incident",
      "target": "incident-56433218",
      "status": "completed",
      "observation": "The NMA perceived the OTN service degradation incident and loaded the incident context."
    },
    {
      "step-id": "step-2",
      "action": "analyze-network-incident",
      "target": "incident-56433218",
      "status": "completed",
      "observation": "The NMA analyzed the incident and identified probable cause information based on alarms and topology correlation."
    },
    {
      "step-id": "step-3",
      "action": "generate-incident-resolution-plan",
      "target": "incident-56433218",
      "status": "completed",
      "observation": "The NMA generated a resolution plan according to the incident resolve-advice and probable cause information."
    },
    {
      "step-id": "step-4",
      "action": "request-confirmation-before-incident-resolution",
      "target": "incident-56433218",
      "status": "pending",
      "observation": "Waiting for confirmation before executing a service-affecting incident resolution action."
    }
  ],
  "result": {
    "summary": "The incident has been analyzed. Probable cause information has been identified, and an incident resolution action is awaiting confirmation.",
    "affected-resources": [
      "incident-56433218",
      "svc-1001",
      "node-a",
      "node-b",
      "port-7",
      "port-3"
    ],
    "output-data": {
      "incident-no": 56433218,
      "status": "updated",
      "ack-status": "acknowledged",
      "next-action": "confirmation-required"
    }
  }
}]]></sourcecode>
      </section>
      <section anchor="appendix-task-notifications">
        <name>Task Notifications</name>
        <t>The following examples show NTI task notifications generated during
        the incident diagnosis and resolution flow.</t>

        <t>Plan-generated notification:</t>
        <sourcecode type="json"><![CDATA[{
  "task-id": "task-2001",
  "intent-id": "intent-1002",
  "notification-type": "plan-generated",
  "time": "2026-06-30T10:03:00Z",
  "payload": {
    "plan-generated": {
      "step-count": 4,
      "estimated-duration": 300
    }
  }
}]]></sourcecode>

        <t>Confirmation-required notification:</t>
        <sourcecode type="json"><![CDATA[{
  "task-id": "task-2001",
  "intent-id": "intent-1002",
  "notification-type": "confirmation-required",
  "time": "2026-06-30T10:03:30Z",
  "payload": {
    "confirmation-required": {
      "confirmation-id": "conf-5001",
      "confirmation-type": "EXECUTION",
      "priority": 9,
      "timeout-seconds": 600,
      "context-schema": "urn:ietf:params:xml:ns:yang:ietf-incident",
      "summary": "Switch service svc-1001 to the protection path to bypass the affected working path resources.",
      "allowed-actions": [
        "approve",
        "reject",
        "escalate-to-human"
      ]
    }
  }
}]]></sourcecode>

        <t>Step-completed notification:</t>
        <sourcecode type="json"><![CDATA[{
  "task-id": "task-2001",
  "intent-id": "intent-1002",
  "notification-type": "step-completed",
  "time": "2026-06-30T10:04:10Z",
  "payload": {
    "step-completed": {
      "step-id": "step-5",
      "observation": "The incident resolution action was executed. The affected service has been switched to the protection path."
    }
  }
}]]></sourcecode>

        <t>Task-completed notification:</t>
        <sourcecode type="json"><![CDATA[{
  "task-id": "task-2001",
  "intent-id": "intent-1002",
  "notification-type": "task-completed",
  "time": "2026-06-30T10:05:00Z",
  "payload": {
    "task-completed": {
      "summary": "Incident 56433218 has been resolved and the related OTN service svc-1001 has been restored. The incident status is updated to cleared.",
      "affected-resources": [
        "incident-56433218",
        "svc-1001",
        "node-a",
        "node-b",
        "port-7",
        "port-3"
      ]
    }
  }
}]]></sourcecode>
      </section>
      
      <section anchor="appendix-confirmation-object">
        <name>Confirmation Object</name>
        <t>The following example shows the full confirmation object exposed as NTI operational state data.</t>
        <sourcecode type="json"><![CDATA[{
  "confirmation-id": "conf-5001",
  "task-id": "task-2001",
  "type": "EXECUTION",
  "priority": 9,
  "timeout-seconds": 600,
  "context-schema": "urn:ietf:params:xml:ns:yang:ietf-incident",
  "context": {
    "incident-no": 56433218,
    "name": "otn-service-degradation",
    "type": "problem",
    "incident-id": "line-fault-svc-1001",
    "service-instance": [
      "svc-1001"
    ],
    "domain": "otn",
    "priority": "critical",
    "status": "updated",
    "ack-status": "acknowledged",
    "category": "network",
    "detail": "The incident has been analyzed. The probable cause is associated with the working path resources between node-a and node-b.",
    "resolve-advice": "Switch service svc-1001 to the protection path to bypass the affected working path resources."
  },
  "allowed-actions": [
    "approve",
    "reject",
    "escalate-to-human"
  ],
  "status": "pending"
}]]></sourcecode>
      </section>
      
<section anchor="appendix-confirmation-resolution-rpc">
  <name>Confirmation Resolution RPC</name>
  <t>The following example shows the input and output of the
  resolve-confirmation RPC.</t>

  <t>Input:</t>
  <sourcecode type="json"><![CDATA[{
  "request-id": "req-1003",
  "correlation-id": "corr-20260630-002",
  "tenant-id": "tenant-1",
  "confirmation-id": "conf-5001",
  "action": "approve",
  "resolved-by": "operator-a"
}]]></sourcecode>

  <t>Output:</t>
  <sourcecode type="json"><![CDATA[{
  "confirmation-id": "conf-5001",
  "task-id": "task-2001",
  "status": "approved",
  "task-state": "EXECUTING"
}]]></sourcecode>
</section>
	  
      
      
      <section anchor="appendix-error-response">
        <name>Error Response</name>
        <sourcecode type="json"><![CDATA[{
  "error-type": "unprocessable-content",
  "error-code": "NTI-INCIDENT-RESOLVE-001",
  "error-message": "The requested incident resolution action cannot be completed because the protection resource is unavailable.",
  "retryable": false,
  "target": "resolve-confirmation.action",
  "details": {
    "incident-resolve-error-info": {
      "incident-no": 56433218,
      "reason": "resource-unavailable",
      "description": "The protection path required to bypass the affected working path is unavailable."
    }
  }
}]]></sourcecode>
      </section>
    </section>
  </back>
</rfc>
