> ## Documentation Index > Fetch the complete documentation index at: https://docs.mangrovesystems.com/llms.txt > Use this file to discover all available pages before exploring further. # List rules > Lists the data rules on a project, most recently created first. Requires a token with Data Rules read permission. ## OpenAPI ````yaml GET /projects/{project_id}/rules openapi: 3.1.0 info: title: Mangrove - API version: 1.1.0 servers: - url: https://app.gomangrove.com/api/v1 security: - sec0: [] paths: /projects/{project_id}/rules: get: summary: List rules description: >- Lists the data rules on a project, most recently created first. Requires a token with Data Rules read permission. operationId: list-project-rules parameters: - name: project_id in: path schema: type: string required: true - name: page in: query schema: type: integer default: 1 - name: page_size in: query schema: type: integer default: 20 responses: '200': description: '200' content: application/json: examples: Result: value: data: - id: rule_Qb3k9TzdL0pWnXyz name: Negative Temp Alert rule_type: alert action: alert method_chain: [] target_type: data_point status: active enabled: true rule_text: '{{data-point.ambient-temperature-c}} < 0' subject_slugs: [] alert_message: Ambient temperature below zero version: 1 effective_from: null effective_to: null model_id: null model_name: null created_by: Sam Okonkwo created_at: '2026-06-03T20:20:29.697Z' updated_at: '2026-06-03T20:20:29.697Z' info: items: 1 page_size: 20 total_items: 1 current_page: 1 next_page: null previous_page: null total_pages: 1 schema: type: object properties: data: type: array items: $ref: '#/components/schemas/Rule' info: type: object '403': description: '403' content: application/json: examples: Result: value: errors: - message: You are not authorized to perform this action deprecated: false components: schemas: Rule: type: object description: >- A data rule on a project. The rule's identity is stable across edits; the condition lives on its latest version. properties: id: type: string description: Rule friendly ID. example: rule_Qb3k9TzdL0pWnXyz name: type: string rule_type: type: string enum: - alert - substitution description: Derived from `action`. Read-only. action: type: string enum: - alert - substitute description: >- `alert` flags the matching record and changes nothing. `substitute` replaces the matching value with one derived from `method_chain`. Only data point rules may substitute. method_chain: type: array description: >- Ordered substitution candidates. The first method that resolves wins. Empty on alert rules. items: $ref: '#/components/schemas/SubstitutionMethod' target_type: type: string enum: - data_point - model description: >- `data_point` evaluates event data as it arrives. `model` evaluates model outputs after a batch calculation. status: type: string enum: - active enabled: type: boolean rule_text: type: string description: The condition, in the rule expression language. example: '{{data-point.ambient-temperature-c}} < 0' subject_slugs: type: array items: type: string description: >- On an alert rule, narrows which of the values the condition reads may be flagged. On a substitute rule, names the single value the rule corrects. alert_message: type: string nullable: true description: >- Shown on the records this rule flags. Required on an alert rule. Optional on a substitute rule, where it covers the records whose method chain resolved nothing, and Mangrove supplies a default. version: type: integer effective_from: type: string format: date nullable: true effective_to: type: string format: date nullable: true model_id: type: string nullable: true description: Model rules only. model_name: type: string nullable: true created_by: type: string created_at: type: string format: date-time updated_at: type: string format: date-time SubstitutionMethod: type: object description: One candidate in a substitute rule's method chain. properties: method: type: string enum: - constant - fallback_to_dpt - forward_fill - backward_fill - trailing_average - trailing_min - trailing_max description: >- `constant` uses a fixed number and always resolves, so no method may follow it. `fallback_to_dpt` copies another data point type on the same event. `forward_fill` and `backward_fill` borrow the nearest earlier or later valid reading. The three trailing methods take the average, lowest or highest reading across a window. params: type: object description: >- `constant` takes `value`. `fallback_to_dpt` takes `slug`. The trailing methods take `window`. The two fills take no parameters. properties: value: type: number description: >- `constant` only. Rejected when the value would itself match the rule's condition. slug: type: string description: >- `fallback_to_dpt` only. A data point type slug on the same event. window: type: object description: Trailing methods only. properties: kind: type: string enum: - rolling - calendar value: type: integer description: Required on a rolling window. Not used on a calendar window. unit: type: string description: >- Rolling windows take `second`, `minute`, `hour`, `day`, `week`, `month` or `year`. Calendar windows take `day`, `week`, `month`, `quarter` or `year`. securitySchemes: sec0: type: apiKey in: header name: Authorization x-bearer-format: '' ````