> ## Documentation Index > Fetch the complete documentation index at: https://docs.dify.ai/llms.txt > Use this file to discover all available pages before exploring further. # Update Chunk > Update a chunk's content, keywords, or answer. Re-triggers indexing for the modified chunk. ## OpenAPI ````yaml /en/api-reference/openapi_knowledge.json post /datasets/{dataset_id}/documents/{document_id}/segments/{segment_id} openapi: 3.0.1 info: title: Knowledge API description: >- API for managing knowledge bases, documents, chunks, metadata, and tags, including creation, retrieval, and configuration. **Note:** A single Knowledge Base API key has permission to operate on all visible knowledge bases under the same account. Please pay attention to data security. version: 1.0.0 servers: - url: '{apiBaseUrl}' description: The base URL for the Knowledge API. variables: apiBaseUrl: default: https://api.dify.ai/v1 description: Actual base URL of the API security: - ApiKeyAuth: [] tags: - name: Knowledge Bases description: >- Operations for managing knowledge bases, including creation, configuration, and retrieval. - name: Documents description: >- Operations for creating, updating, and managing documents within a knowledge base. - name: Chunks description: Operations for managing document chunks and child chunks. - name: Metadata description: >- Operations for managing knowledge base metadata fields and document metadata values. - name: Tags description: Operations for managing knowledge base tags and tag bindings. - name: Models description: Operations for retrieving available models. - name: Knowledge Pipeline description: >- Operations for managing and running knowledge pipelines, including datasource plugins and pipeline execution. paths: /datasets/{dataset_id}/documents/{document_id}/segments/{segment_id}: post: tags: - Chunks summary: Update Chunk description: >- Update a chunk's content, keywords, or answer. Re-triggers indexing for the modified chunk. operationId: updateSegment parameters: - name: dataset_id in: path required: true schema: type: string format: uuid description: Knowledge base ID. - name: document_id in: path required: true schema: type: string format: uuid description: Document ID. - name: segment_id in: path required: true schema: type: string format: uuid description: Chunk ID. requestBody: required: true content: application/json: schema: type: object required: - segment properties: segment: type: object properties: content: type: string description: Chunk text content. answer: type: string description: Answer content for QA mode. keywords: type: array items: type: string description: Keywords for the chunk. enabled: type: boolean description: Whether the chunk is enabled. regenerate_child_chunks: type: boolean default: false description: Whether to regenerate child chunks. attachment_ids: type: array items: type: string description: Attachment file IDs. summary: type: string nullable: true description: Summary content for summary index. description: Chunk data to update. responses: '200': description: Chunk updated successfully. content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/Segment' doc_form: type: string description: Document chunking mode used by this document. examples: success: summary: Response Example value: data: id: f3d1c7be-9f3a-40d8-8eb8-3a1ef9c3f2c1 position: 1 document_id: a8e0e5b5-78c6-4130-a5ce-25feb0e0b4ac content: Dify is an open-source LLM app development platform. sign_content: '' answer: '' word_count: 9 tokens: 12 keywords: - dify - platform - llm index_node_id: a1b2c3d4-e5f6-7890-abcd-000000000001 index_node_hash: abc123def456 hit_count: 0 enabled: true disabled_at: null disabled_by: null status: completed created_by: ad313dd6-ef04-4dd1-a5b0-c0f0b9e2e7e4 created_at: 1741267200 updated_at: 1741267200 updated_by: ad313dd6-ef04-4dd1-a5b0-c0f0b9e2e7e4 indexing_at: 1741267200 completed_at: 1741267200 error: null stopped_at: null child_chunks: [] attachments: [] summary: null doc_form: text_model components: schemas: Segment: type: object properties: id: type: string description: Unique identifier of the chunk. position: type: integer description: Position of the chunk within the document. document_id: type: string description: ID of the document this chunk belongs to. content: type: string description: Text content of the chunk. sign_content: type: string description: Signed content hash for integrity verification. answer: type: string description: Answer content, used in Q&A mode documents. word_count: type: integer description: Word count of the chunk content. tokens: type: integer description: Token count of the chunk content. keywords: type: array description: Keywords associated with this chunk for keyword-based retrieval. items: type: string index_node_id: type: string description: ID of the index node in the vector store. index_node_hash: type: string description: Hash of the indexed content, used to detect changes. hit_count: type: integer description: Number of times this chunk has been matched in retrieval queries. enabled: type: boolean description: Whether the chunk is enabled for retrieval. disabled_at: type: number nullable: true description: Timestamp when the chunk was disabled. `null` if enabled. disabled_by: type: string nullable: true description: ID of the user who disabled the chunk. `null` if enabled. status: type: string description: >- Current indexing status of the chunk, e.g. `completed`, `indexing`, `error`. created_by: type: string description: ID of the user who created the chunk. created_at: type: number description: Creation timestamp (Unix epoch in seconds). updated_at: type: number description: Last update timestamp (Unix epoch in seconds). updated_by: type: string description: ID of the user who last updated the chunk. indexing_at: type: number nullable: true description: Timestamp when indexing started. `null` if not yet started. completed_at: type: number nullable: true description: Timestamp when indexing completed. `null` if not yet completed. error: type: string nullable: true description: Error message if indexing failed. `null` when no error. stopped_at: type: number nullable: true description: Timestamp when indexing was stopped. `null` if not stopped. child_chunks: type: array description: >- Child chunks belonging to this chunk. Only present for hierarchical mode documents. items: $ref: '#/components/schemas/ChildChunk' attachments: type: array description: Files attached to this chunk. items: type: object properties: id: type: string description: Attachment file identifier. name: type: string description: Original file name. size: type: integer description: File size in bytes. extension: type: string description: File extension. mime_type: type: string description: MIME type of the file. source_url: type: string description: URL to access the attachment. summary: type: string nullable: true description: >- AI-generated summary of the chunk content. `null` if summary indexing is not enabled. ChildChunk: type: object properties: id: type: string description: Unique identifier of the child chunk. segment_id: type: string description: ID of the parent chunk this child chunk belongs to. content: type: string description: Text content of the child chunk. position: type: integer description: Position of the child chunk within the parent chunk. word_count: type: integer description: Word count of the child chunk content. type: type: string description: >- How the child chunk was created. `automatic` for system-generated, `custom` for manually created. created_at: type: number description: Creation timestamp (Unix epoch in seconds). updated_at: type: number description: Last update timestamp (Unix epoch in seconds). securitySchemes: ApiKeyAuth: type: http scheme: bearer bearerFormat: API_KEY description: >- API Key authentication. For all API requests, include your API Key in the `Authorization` HTTP Header, prefixed with `Bearer `. Example: `Authorization: Bearer {API_KEY}`. **Strongly recommend storing your API Key on the server-side, not shared or stored on the client-side, to avoid possible API-Key leakage that can lead to serious consequences.** ````