> ## Documentation Index > Fetch the complete documentation index at: https://docs.cuadra.ai/llms.txt > Use this file to discover all available pages before exploring further. # Update Particle in System Prompt > Update a particle's order or version pinning in a system prompt. ## OpenAPI ````yaml patch /v1/system-prompts/{system_prompt_id}/particles/{particle_id} openapi: 3.1.0 info: title: Cuadra AI API description: >- REST API for AI-powered chat, RAG, and multi-channel messaging. Full documentation at https://docs.cuadra.ai version: 1.0.0 contact: name: Cuadra AI Support url: https://cuadra.ai/support email: support@cuadra.ai license: name: Proprietary url: https://cuadra.ai/terms termsOfService: https://cuadra.ai/terms servers: - url: https://api.cuadra.ai description: Production security: - bearerAuth: [] - oauth2: [] tags: - name: Health description: >- System health monitoring and readiness checks. Essential for load balancers and deployment automation. - name: Models description: >- Manage custom AI model configurations derived from base models. Create, update, and delete with flexible pricing and token limits. - name: Chats description: >- Interact with AI models for intelligent chat completions. Supports streaming and non-streaming modes with message history. - name: Files description: >- Manage file uploads for chat attachments and dataset knowledge bases. Supports automatic processing, chunking, and embedding for RAG. - name: Datasets description: >- Manage RAG knowledge base datasets with versioning and semantic search. Organize uploaded files into searchable knowledge bases. - name: Particles description: >- Manage reusable system prompt particles for AI model behavior. Particles are modular components (role, tone, guardrails, constraints, format) that compose into system prompts. - name: System Prompts description: >- Compose particles into complete system prompts for AI models. System prompts define model behavior through ordered particle compositions with support for version pinning and token budget validation. - name: Usage description: >- Monitor and analyze API usage with detailed token counting. Track usage across models, tenants, and time periods. - name: Artifacts description: >- Manage rich content artifacts generated during chat conversations. Supports markdown, code, HTML, SVG, and Mermaid diagrams. paths: /v1/system-prompts/{system_prompt_id}/particles/{particle_id}: patch: tags: - System Prompts summary: Update Particle in System Prompt description: Update a particle's order or version pinning in a system prompt. operationId: updateSystemPromptParticle parameters: - name: system_prompt_id in: path required: true schema: type: string description: System Prompt ID title: System Prompt Id description: System Prompt ID - name: particle_id in: path required: true schema: type: string description: Particle ID title: Particle Id description: Particle ID - name: Idempotency-Key in: header required: false schema: anyOf: - type: string - type: 'null' title: Idempotency-Key requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SystemPromptParticleUpdate' responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/SystemPromptParticleOut' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' components: schemas: SystemPromptParticleUpdate: properties: particleVersionId: anyOf: - type: string - type: 'null' title: Particleversionid description: Version ID to pin (NULL = use current) examples: - pv_abc123 order: anyOf: - type: integer minimum: 0 - type: 'null' title: Order description: Updated order in the composition examples: - 1 type: object title: SystemPromptParticleUpdate description: Request schema for updating a particle association. SystemPromptParticleOut: properties: id: type: string title: Id description: Association ID examples: - spa_abc123 particleId: type: string title: Particleid description: Particle ID examples: - part_xyz789 particleName: anyOf: - type: string - type: 'null' title: Particlename description: Particle name (derived) examples: - Professional Tone particleCategory: anyOf: - $ref: '#/components/schemas/ParticleCategory' - type: 'null' description: Particle category (derived) examples: - tone particleVersionId: anyOf: - type: string - type: 'null' title: Particleversionid description: Pinned version ID (NULL = current) examples: - pv_abc123 pinnedVersion: anyOf: - type: integer - type: 'null' title: Pinnedversion description: Pinned version number (derived) examples: - 2 order: type: integer title: Order description: Order in composition examples: - 0 tokenCount: anyOf: - type: integer - type: 'null' title: Tokencount description: Token count of the particle content examples: - 25 type: object required: - id - particleId - order title: SystemPromptParticleOut description: Response schema for a particle within a system prompt. HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError ParticleCategory: type: string enum: - role - tone - guardrails - constraints - format title: ParticleCategory description: Categories for organizing particles by their purpose. ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type type: object required: - loc - msg - type title: ValidationError securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: JWT token from Stytch B2B authentication (magic link, SSO, or M2M) oauth2: type: oauth2 flows: clientCredentials: tokenUrl: https://auth.cuadra.ai/oauth/token scopes: chats:invoke: Invoke chat completions (billable) chats:read: Read and list chats chats:write: Create and update chats chats:delete: Delete chats chats:admin: Full chat access (read/write/delete/invoke) models:read: Read model configurations models:write: Create and update models models:delete: Delete models models:admin: Full access to models (grants read + write + delete) datasets:read: Read and list datasets and snapshots datasets:write: Create and update datasets and snapshots datasets:delete: Delete datasets and snapshots datasets:admin: Full dataset access (read/write/delete) files:read: Read, list, and download files files:write: Upload, associate, and reprocess files files:delete: Delete files (single and bulk) files:admin: Full access to files (grants read + write + delete) particles:read: View particles and particle versions particles:write: Create and update particles particles:delete: Delete particles particles:admin: Full particle access (read/write/delete) system-prompts:read: View system prompts and compositions system-prompts:write: Create and update system prompts system-prompts:delete: Delete system prompts system-prompts:admin: Full system prompt access (read/write/delete) usage:read: Read usage and billing information usage:admin: Full access to usage data (grants read) connections:read: View external connections and sync status connections:write: Create and update external connections connections:delete: Delete connections and sync configurations connections:admin: Full connection access (read/write/delete) channels:read: View channels and channel configuration channels:write: Create and update channels channels:delete: Delete channels and release phone numbers channels:admin: Full channel access (read/write/delete) org:admin: Full resource access, manage members org:owner: 'Owner: all access including billing' chat:write: Delete and manage chats ````