> ## Documentation Index > Fetch the complete documentation index at: https://docs.fitsociety.io/llms.txt > Use this file to discover all available pages before exploring further. # Swap a prescribed plan-day exercise (by plan exercise id) > Swaps the exercise prescribed at a plan-day slot on the client's ASSIGNED plan, keyed by `planExerciseId`. Plan-scoped (not session-scoped): it works from the plan-day screen even before anything is logged — no session or performance is required, so it covers the case where `performanceId` is null. Started or recorded performances keep their original exercise, type, sets and targets, including active sessions. Only untouched placeholders (no sets, completion, start or end) can be repointed or discarded for the replacement. The prescribed exercise on the assigned plan is repointed at `newExerciseId`. Coaches act for a client by passing `clientId`. Requires the workout_sessions:write scope. This operation maps to /app/v1/workout/performance/plans/:planId/moments/:planMomentId/exercises/:planExerciseId/swap and retains its Workout V2 permission, feature-flag, and resource-scope checks. The clientId path parameter is resolved inside the company bound to the Public API token when present. ## OpenAPI ````yaml /openapi/public-v1.json post /public/v1/workout/performance/plans/{planId}/moments/{planMomentId}/exercises/{planExerciseId}/swap openapi: 3.1.0 info: title: FITsociety Public API v1 version: 1.0.0 description: >- Developer Public API endpoints under `/public/v1`. This reference is filtered to OAuth/Bearer Public API resources and excludes provider callback receivers, storefront routes, public widgets, wishlist routes, and access-device validation endpoints. contact: name: FITsociety Engineering servers: - url: https://api.fitsociety.io description: Production security: [] tags: - name: Workout description: >- Workout V2 libraries, programmes, client plans, calendars, sessions, groups, settings and progress. AI operations are excluded. - name: OAuth description: Public API OAuth endpoints for server-to-server client credentials. - name: Health description: Public API token health checks. - name: Platform description: >- Inspect Public API client context, capabilities, scopes, and redacted audit logs. - name: Company Catalog description: Read and manage company profile metadata and locations. - name: Clients description: >- Create and manage clients through the Public API using Bearer access tokens. - name: Coaches description: Retrieve coaches for the authenticated company via integrations. - name: Calendar Events description: Read Public API calendar events. - name: Calendar Templates description: >- Read and manage event types and event templates used by calendar availability and bookings. - name: Calendar Extensions description: >- Read recurring bookings, booking requests, calendar tasks, and availability closure metadata. - name: Availability description: Read bookable availability slots and signed availability tokens. - name: Availability Management description: >- Manage coach and location availability templates used to derive bookable slots. - name: Bookings description: Read and manage Public API bookings. - name: Finance description: >- Read invoices, transactions, products, subscriptions, and memberships with guarded finance writes. - name: Credits description: >- Read company-wide and client-scoped credit allocations, mutations, and guarded credit adjustments. - name: Exports description: >- Create and monitor asynchronous company exports through Public API Bearer endpoints. - name: Webhooks description: >- Manage outbound webhook subscriptions and inspect delivery attempts through Public API Bearer endpoints. - name: Measurements description: Read and write client measurement entries. - name: Progress Photos description: Read client progress photo metadata and short-lived signed media URLs. - name: Forms description: Read, create, update, and archive company form templates. - name: Intakes description: Assign intake forms and read client intake assignments and submissions. - name: Check-ups description: >- Schedule and cancel client check-ups and read their status and submissions. - name: Documents description: >- Read client document and folder metadata, register external document links, update metadata, and archive documents from Public API listings. Binary upload, permanent deletion, and company-wide document management are not exposed. - name: Habits description: Read habits and habit entries. - name: Goals description: Read client goal summaries. - name: Conversations description: >- Read and manage direct and group chat conversations through the Public API. - name: Reports description: Read aggregate attendance, revenue, and retention summaries. paths: /public/v1/workout/performance/plans/{planId}/moments/{planMomentId}/exercises/{planExerciseId}/swap: post: tags: - Workout summary: Swap a prescribed plan-day exercise (by plan exercise id) description: >- Swaps the exercise prescribed at a plan-day slot on the client's ASSIGNED plan, keyed by `planExerciseId`. Plan-scoped (not session-scoped): it works from the plan-day screen even before anything is logged — no session or performance is required, so it covers the case where `performanceId` is null. Started or recorded performances keep their original exercise, type, sets and targets, including active sessions. Only untouched placeholders (no sets, completion, start or end) can be repointed or discarded for the replacement. The prescribed exercise on the assigned plan is repointed at `newExerciseId`. Coaches act for a client by passing `clientId`. Requires the workout_sessions:write scope. This operation maps to /app/v1/workout/performance/plans/:planId/moments/:planMomentId/exercises/:planExerciseId/swap and retains its Workout V2 permission, feature-flag, and resource-scope checks. The clientId path parameter is resolved inside the company bound to the Public API token when present. operationId: >- publicWorkoutpostPublicV1WorkoutPerformancePlansPlanIdMomentsPlanMomentIdExercisesPlanExerciseIdSwap parameters: - name: Idempotency-Key in: header required: true schema: type: string minLength: 1 maxLength: 200 example: booking-create-20260714-001 description: >- Required for Public API write requests. Reusing the same key with the same method, path, and body replays the stored successful response; reusing it with a different request returns `409 idempotency.conflict`. - in: path name: planId required: true description: Assigned plan (template) id. schema: type: string example: 67f1234567890abcdef1234 - in: path name: planMomentId required: true description: Plan day (moment) id. schema: type: string example: 67f1234567890abcdef1234 - in: path name: planExerciseId required: true description: The prescribed exercise subdoc id (the plan-day slot) to swap. schema: type: string example: 67f1234567890abcdef1234 requestBody: required: true content: application/json: schema: $ref: >- #/components/schemas/PublicWorkoutSourcePOSTAppV1WorkoutPerformancePlansPlanIdMomentsPlanMomentIdExercisesPlanExerciseIdSwapRequest example: newExerciseId: 67f1234567890abcdef4321 responses: '200': description: 'Swap result: the repointed slot plus any discarded performance ids.' content: application/json: schema: allOf: - $ref: '#/components/schemas/PublicApiWriteSuccessResponse' - type: object properties: data: $ref: >- #/components/schemas/PublicWorkoutSourcePOSTAppV1WorkoutPerformancePlansPlanIdMomentsPlanMomentIdExercisesPlanExerciseIdSwapResponse200 examples: success: summary: Successful response value: data: planId: 67f1234567890abcdef1234 planMomentId: 67f1234567890abcdef1234 planExerciseId: 67f1234567890abcdef1234 oldExerciseId: 67f1234567890abcdef1234 newExerciseId: 67f1234567890abcdef1234 removedPerformanceIds: - 67f1234567890abcdef1234 unchanged: false meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 idempotency: replayed: false '400': description: >- A path id is invalid, the new exercise id is invalid, required user context is missing, or the slot is part of a superset that already holds the target exercise (`DUPLICATE_EXERCISE_IN_SUPERSET`). The same exercise may appear more than once in a day, but not twice within one superset. content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: invalidRequest: summary: Invalid request value: error: code: 400 key: request.invalid message: The request is invalid. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 idempotencyRequired: summary: Missing Idempotency-Key value: error: code: 400 key: idempotency.required message: >- Idempotency-Key header is required for Public API write requests. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 idempotencyInvalid: summary: Invalid Idempotency-Key value: error: code: 400 key: idempotency.invalid message: Idempotency-Key header must be 200 characters or fewer. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 '401': $ref: '#/components/schemas/ErrorResponse' content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: missingBearer: summary: Missing Bearer token value: error: code: 401 key: auth.missing_bearer message: Authorization Bearer token is required. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 invalidToken: summary: Invalid or expired token value: error: code: 401 key: auth.invalid_token message: The access token is invalid or expired. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 invalidClient: summary: Inactive or revoked client value: error: code: 401 key: auth.invalid_client message: The Public API client is inactive or revoked. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 '403': $ref: '#/components/schemas/ErrorResponse' content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: insufficientScopes: summary: Missing required scope value: error: code: 403 key: scopes.insufficient message: The access token does not include the required scope. details: requiredScopes: - required:scope meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 '404': description: >- The assigned plan day or the prescribed exercise slot was not found in the client scope. content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: notFound: summary: Resource not found value: error: code: 404 key: resource.not_found message: The requested Public API resource was not found. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 '409': description: >- The target exercise is the one already prescribed at this slot (`EXERCISE_ALREADY_IN_SESSION`). content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: idempotencyConflict: summary: Idempotency-Key conflict value: error: code: 409 key: idempotency.conflict message: >- Idempotency-Key was already used with a different request. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 idempotencyInProgress: summary: Idempotency-Key in progress value: error: code: 409 key: idempotency.in_progress message: >- Idempotency-Key is already processing for this Public API client. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 '422': description: Request body is empty. content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: emptyBody: summary: Empty or invalid JSON object body value: error: code: 422 key: EMPTY_BODY message: Request body must be a non-empty JSON object. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 '429': $ref: '#/components/schemas/ErrorResponse' content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: rateLimitExceeded: summary: Rate limit exceeded value: error: code: 429 key: rate_limit.exceeded message: Too many Public API requests. Retry later. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 0 resetSeconds: 1 retryAfterSeconds: 1 '500': description: Unexpected server error. content: application/json: schema: $ref: '#/components/schemas/PublicApiError' examples: serverInternalError: summary: Unexpected server error value: error: code: 500 key: server.internal_error message: An unexpected Public API server error occurred. meta: requestId: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: limit: 10 remaining: 9 resetSeconds: 1 security: - PublicBearerAuth: [] x-codeSamples: - lang: cURL label: cURL source: >- curl -X POST "https://api.fitsociety.io/public/v1/workout/performance/plans/{planId}/moments/{planMomentId}/exercises/{planExerciseId}/swap" \ -H "Authorization: Bearer " \ -H "Idempotency-Key: " \ -H "Content-Type: application/json" \ -d '{}' components: schemas: PublicWorkoutSourcePOSTAppV1WorkoutPerformancePlansPlanIdMomentsPlanMomentIdExercisesPlanExerciseIdSwapRequest: type: object required: - newExerciseId properties: newExerciseId: type: string example: 67f1234567890abcdef1234 clientId: type: string example: 67f1234567890abcdef1234 description: Required only when a coach acts on behalf of a linked client. PublicApiWriteSuccessResponse: type: object additionalProperties: false required: - data - meta properties: data: type: object meta: $ref: '#/components/schemas/PublicApiWriteMeta' PublicWorkoutSourcePOSTAppV1WorkoutPerformancePlansPlanIdMomentsPlanMomentIdExercisesPlanExerciseIdSwapResponse200: type: object properties: planId: type: string example: 67f1234567890abcdef1234 planMomentId: type: string example: 67f1234567890abcdef1234 planExerciseId: type: string example: 67f1234567890abcdef1234 oldExerciseId: oneOf: - type: string example: 67f1234567890abcdef1234 - type: 'null' newExerciseId: type: string example: 67f1234567890abcdef1234 removedPerformanceIds: type: array description: >- Ids of in-progress performances discarded by the swap (empty when nothing was logged). items: type: string example: 67f1234567890abcdef1234 unchanged: type: boolean description: True when newExerciseId already occupied the slot (no-op). example: false PublicApiError: type: object additionalProperties: false required: - error - meta properties: error: type: object additionalProperties: false required: - code - key - message properties: code: type: integer example: 401 key: type: string example: auth.invalid_token message: type: string example: The access token is invalid. details: type: object additionalProperties: true meta: $ref: '#/components/schemas/PublicApiMeta' ErrorResponse: allOf: - $ref: '#/components/schemas/StandardResponse' - example: status: 401 error: true message: MISSING_AUTH PublicApiWriteMeta: type: object additionalProperties: false required: - requestId properties: requestId: type: string description: Stable request correlation id. Mirrors `X-Request-Id` when supplied. example: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: $ref: '#/components/schemas/PublicApiRateLimitMeta' idempotency: type: object additionalProperties: false properties: replayed: type: boolean description: >- True when the response was replayed from a previous request with the same `Idempotency-Key`. example: true PublicApiMeta: type: object additionalProperties: false required: - requestId properties: requestId: type: string description: Stable request correlation id. Mirrors `X-Request-Id` when supplied. example: 4f849d7d-f4f1-45cc-b4b7-3984a3d17f83 rateLimit: $ref: '#/components/schemas/PublicApiRateLimitMeta' StandardResponse: type: object properties: status: type: integer example: 200 error: type: boolean example: false message: type: string example: SUCCESS required: - status - error - message PublicApiRateLimitMeta: type: object additionalProperties: false properties: limit: type: integer example: 10 remaining: type: integer example: 9 resetSeconds: type: integer description: Seconds until the current rate limit window resets. example: 1 retryAfterSeconds: type: integer description: Present when the request was rate limited. example: 1 securitySchemes: PublicBearerAuth: type: http scheme: bearer bearerFormat: Opaque description: >- Public API access token issued by `/public/v1/oauth/token`. Example: `Authorization: Bearer fspt_...`. Each resource request rechecks the token company's current provider access. Disabling access blocks existing tokens with `403 auth.provider_unavailable`. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.