> ## Documentation Index > Fetch the complete documentation index at: https://docs.fiddler.ai/llms.txt > Use this file to discover all available pages before exploring further. # Edit a dataset item > Edit one dataset item by appending a revision under a new committed version. Nothing is overwritten and nothing is removed: the previous revision stays readable at every earlier `?version=`. **This is a merge, not a replace.** A field the request omits keeps its current value; a field the request sends replaces that field *wholesale*. There is no deep merge inside the JSON buckets — sending `inputs` replaces the whole `inputs` object, which is what lets a caller remove a key from it. Note that an omitted field and a field sent as `null` are different things: `null` clears the field, except `inputs`, which cannot be cleared. **A no-op writes nothing.** If the resulting content is identical to the item's current content, nothing is written, no new version is created, and the response is still 200 with the unchanged item. `null` and empty are normalised before the comparison, so clearing an already-empty field is a no-op too. `base_version` is required, for an optimistic-concurrency check: the edit is refused with 409 if any revision of *this item* has landed above that version. An older `base_version` is still accepted if this item has not changed since it. A retry of an edit whose response was lost therefore gets a 409; re-read the item to see that it was applied. ## OpenAPI ````yaml PATCH /v3/evals/datasets/{dataset_id}/items/{item_id} openapi: 3.0.3 info: title: Fiddler API - 2.0 description: APIs to interact with Fiddler termsOfService: https://fiddler.ai/about/terms contact: email: support@fiddler.ai license: name: Proprietary url: '2.0' version: '2.0' servers: [] security: - BearerAuth: [] tags: - name: access-key description: CRUD operations for API keys - name: agent-v3 description: CRUD for the Agent Registry (Stage 1, manual entries) - name: aggregation-invalidation-request-v3 description: Endpoints related to retrieving aggregation invalidation requests - name: alert-rules-v3 description: CRUD for Alert Rules, Summary, and Stats APIs - name: application-v3 - name: auth description: Authentication strategies and login flows - name: baseline-v3 description: CRUD for baseline - name: catalog-v3 description: >- Entity catalog provides paginated, searchable discovery of entity names (attribute keys, agent names, span types, span names, score names, evaluator config names) and their distinct values. Powered by ClickHouse materialized views — no worker or PostgreSQL dependency. - name: chart-annotation-v3 description: Endpoints related to retrieving chart annotations - name: chart-v3 description: CRUD for chart - name: queries-v3 description: v3 queries API - name: configuration-v3 description: > Read and change runtime configurations (Config Manager) for your organization, its projects, and its models. **Private preview.** These endpoints accept requests on every deployment. Whether a saved value takes effect depends on two deployment settings that are off by default: one makes Fiddler read stored values, and the other runs the configuration worker, which applies retention changes to stored data. Contact your Fiddler Customer Success Manager before using these endpoints. This reference documents the data retention (TTL) settings: `PROD_EVENTS_TTL_DAYS`, `GENAI_TRACES_TTL_DAYS`, and `GENAI_METRICS_TTL_DAYS`. The API accepts other registered settings too; contact your Fiddler Customer Success Manager before changing any of them. **Retention settings permanently delete data** once it is older than the configured period. When existing data is affected depends on the setting; see each setting's description. - name: cost-evaluators-v3 description: > Paginated roll-up of per-evaluator LLM cost and token usage, aggregated hourly. Available only on deployments with evaluator cost reporting enabled. - name: custom-metrics-v3 - name: dimensionality-reduction-v3 - name: environment-v3 description: Endpoints related to environment management - name: evals - name: datasets - name: evaluation-v3 - name: evaluator-v3 - name: rule-evaluators-v3 - name: experiment-v3 - name: explainability-v3 - name: llm_rca-v3 - name: file-upload description: Endpoints related to file uploading. - name: fql-expressions-v3 description: > Endpoints for listing FQL (Fiddler Query Language) functions available for GenAI custom metrics. Used by the frontend for autocomplete and signature hints in the FQL editor. - name: genai-alert-rules-v3 description: CRUD API for GenAI Alert Rules - name: genai-custom-metrics-v3 description: API for GenAI Custom Metrics - name: genai-filters-v3 description: API for GenAI Filters - name: genai-metrics-v3 description: >- Endpoints for pre-aggregated GenAI metrics. All metric data is pre-aggregated hourly by a Celery-based metric collector; no real-time aggregation is performed at request time. - name: guardrails-api description: Endpoints related to retrieving Guardrails specific data - name: ingestion-v3 - name: intercom-api description: Endpoints related to intercom APIs - name: jobs-v3 - name: llm-gateway-v3 - name: auth-login - name: auth-logout - name: mcp-client-setup-v3 description: Endpoints for retrieving MCP client setup instructions. - name: metrics-v3 description: Metrics endpoints - name: model-v3 - name: dashboard-v3 - name: model-deployment-v3 - name: monitoring-summary-v3 - name: histograms-v3 - name: organization-roles-v3 description: Update user org role - name: organization-settings-v3 description: Update organization settings such as timezone, email configuration, etc. - name: pagerduty-api description: CRUD for Pagerduty services. - name: project-v3 - name: project-roles-v3 description: Project role assignment management - name: scores-v3 description: Unified CRUD for scores and annotations - name: searchable-text-key-v3 description: >- Manage the global searchable text keys table that controls which OTel attribute keys are routed to the full-text-searchable `ValueContent` column in the unified attributes table. Changes propagate to the backing ClickHouse dictionary within 1-2 minutes and affect all tenants. - name: segments-v3 - name: semantic-mapping-v3 description: >- Manage the global semantic name mappings table that maps raw OTel attribute keys to canonical semantic concepts. Changes propagate to the backing ClickHouse dictionary within 1-2 minutes and affect all tenants. - name: server-info-v3 description: Endpoints related to retrieving server information - name: service-account description: > Service accounts and their API keys. A human Org Admin manages the service accounts of their own organization: create, read, update, and enable/disable (there is no delete — an account is disabled instead), and issue, rename, enable/disable, and revoke each account's API keys (a key's expiry is fixed at creation and changed only by rotating the key). An API key is an `fks_` secret that inherits the account's grants and cannot manage service accounts; an active, unexpired key must be disabled before it can be revoked, and it authenticates only while both it and its account are active. Scopes here are capability scopes (what the account may do), not OAuth scopes. - name: sessions-v3 description: v3 session APIs - name: span-v3 - name: team-roles-v3 - name: team-v3 - name: traces-v3 description: v3 trace api for monitoring - name: fetch-sessions-v3 description: v3 fetch sessions api for monitoring - name: user-access-key description: > CRUD operations for user API keys. All endpoints are user-scoped — each user can only operate on their own API keys. No one including Org admins have access to other users' API keys. - name: users-v3 - name: version-compatibility-v3 - name: webhooks externalDocs: url: https://docs.fiddler.ai description: Find out more about Fiddler paths: /v3/evals/datasets/{dataset_id}/items/{item_id}: parameters: - name: dataset_id in: path description: Dataset UUID required: true schema: type: string format: uuid - name: item_id in: path description: Dataset item UUID required: true schema: type: string format: uuid patch: tags: - evals - datasets summary: Edit a dataset item description: >- Edit one dataset item by appending a revision under a new committed version. Nothing is overwritten and nothing is removed: the previous revision stays readable at every earlier `?version=`. **This is a merge, not a replace.** A field the request omits keeps its current value; a field the request sends replaces that field *wholesale*. There is no deep merge inside the JSON buckets — sending `inputs` replaces the whole `inputs` object, which is what lets a caller remove a key from it. Note that an omitted field and a field sent as `null` are different things: `null` clears the field, except `inputs`, which cannot be cleared. **A no-op writes nothing.** If the resulting content is identical to the item's current content, nothing is written, no new version is created, and the response is still 200 with the unchanged item. `null` and empty are normalised before the comparison, so clearing an already-empty field is a no-op too. `base_version` is required, for an optimistic-concurrency check: the edit is refused with 409 if any revision of *this item* has landed above that version. An older `base_version` is still accepted if this item has not changed since it. A retry of an edit whose response was lost therefore gets a 409; re-read the item to see that it was applied. operationId: updateEvalsDatasetItemV3 requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/PatchEvalDatasetItemRequest' responses: '200': description: >- The item as it reads at the version this edit committed, and that version. For a no-op, the unchanged item and the current version it was compared against. `dataset_version.version` is safe as `base_version` only for this item; re-read before editing others. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiResponse' - type: object properties: data: type: object required: - item - dataset_version properties: item: $ref: '#/components/schemas/DatasetItem' dataset_version: $ref: '#/components/schemas/DatasetVersionCompact' '400': $ref: '#/components/responses/400' '401': $ref: '#/components/responses/401' '403': $ref: '#/components/responses/403' '404': description: >- The dataset does not exist, the dataset has no live item with that id (unknown, belonging to another dataset, or already deleted), or `base_version` names no committed version of this dataset. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '409': description: >- The write conflicted and no changes were made; switch on `errors[0].reason` to decide whether to retry. content: application/json: schema: $ref: '#/components/schemas/DatasetWriteConflictResponse' '500': $ref: '#/components/responses/500' '503': description: >- The data store was unavailable or too slow. No changes were made; retry with backoff. `errors[0].reason` is `DatasetItemsWriteUnavailable`. content: application/json: schema: $ref: '#/components/schemas/DatasetItemsWriteUnavailableResponse' components: schemas: PatchEvalDatasetItemRequest: type: object description: >- Partial update of one dataset item. Send only the fields you want to change: an omitted field keeps its current value, while a field sent as `null` clears it (except `inputs`). An unknown field is a 400. A field that *is* sent replaces that field wholesale — there is no deep merge inside the JSON buckets. required: - base_version properties: inputs: type: object additionalProperties: true description: >- Replaces the whole `inputs` object. Not deep-merged, so this is how a key is removed from it. example: question: What is the capital of France? expected_outputs: type: object nullable: true additionalProperties: true description: Replaces the whole `expected_outputs` object. metadata: type: object nullable: true additionalProperties: true description: Replaces the whole `metadata` object. extras: type: object nullable: true additionalProperties: true description: Replaces the whole `extras` object. source_name: type: string nullable: true description: Name of the source for this dataset item. source_id: type: string nullable: true description: ID of the item in the source. base_version: allOf: - $ref: '#/components/schemas/DatasetVersionReference' description: >- Optimistic-concurrency check: the version the caller believes it is editing. The edit is refused with 409 if any revision of *this item* has landed above that version — not "if this is not the dataset's newest version", so an edit to an item that is merely old is not rejected. ApiResponse: type: object description: | Response object for standard API responses. properties: api_version: type: string default: '3.0' enum: - '2.0' - '3.0' description: | API version. kind: type: string default: NORMAL enum: - NORMAL description: | Type of response, indicating a normal response. DatasetItem: type: object description: Details of a dataset item required: - id - inputs - created_at - updated_at properties: id: description: Unique identifier of the dataset item type: string format: uuid readOnly: true inputs: type: object description: JSON object representing the inputs for this dataset item. additionalProperties: true expected_outputs: type: object nullable: true description: JSON object representing the expected outputs for this dataset item. additionalProperties: true metadata: type: object nullable: true description: JSONB field for unstructured metadata. additionalProperties: true extras: type: object nullable: true description: JSONB field for unstructured extra data. additionalProperties: true source_name: type: string nullable: true description: Name of the source for this dataset item. source_id: type: string nullable: true description: >- ID of the item in the source. For items created from spans (`source_name` = `span`), this is `{source_application_uuid}:{trace_id}:{span_id}`, recording which application the span was promoted from. created_at: type: string format: date-time readOnly: true updated_at: type: string format: date-time readOnly: true DatasetVersionCompact: type: object title: DatasetVersionCompact description: > Compact version of an evaluation dataset version which can be included in the response of relevant APIs. required: - id - version - tag properties: id: type: string format: uuid description: | Unique identifier of the dataset version. version: type: integer description: > Per-dataset version number, accepted by the `version` query parameter. tag: type: string nullable: true description: | Reserved for future version tagging; always null today. ErrorResponse: type: object description: | Response object for errors returned by the API. properties: api_version: type: string default: '3.0' enum: - '2.0' - '3.0' description: | API version of the response. kind: type: string default: ERROR enum: - ERROR description: | Type of response, usually indicating an error. error: type: object properties: code: type: integer format: int32 description: > Represents the code for this error, typically an HTTP response code. default: 400 enum: - 400 - 401 - 403 - 404 - 409 - 410 - 422 - 429 - 500 - 501 - 503 message: type: string description: > A human-readable message providing more details about the error. If there are multiple errors, it will be the message for the first error. example: Resource Not Found errors: type: array description: > Container for additional information regarding the error, especially for multiple errors. items: type: object properties: reason: type: string description: > Unique identifier for this error, different from the error code. example: ResourceNotFoundException message: type: string description: > A human-readable message providing more details about the error. If there is only one error, this field will match error.message. example: Resource Not Found help: type: string description: > Link to support or documentation providing more information on the error. DatasetWriteConflictResponse: description: >- Error body of a `409` from a dataset write. No changes were made. `errors[0].reason` is the machine-readable discriminator. Kinds of conflict need different handling, so switch on it rather than on the status code alone: * `DatasetVersionCommitRace` — **transient; safe to retry unattended.** The write took too long to commit and another write took its place. The request is still valid, and replaying it commits under a new version. * `DatasetVersionSaveInProgress` — **transient; retry with backoff.** Another save holds the dataset. The request is still valid; resend it unchanged. * `DatasetItemStaleBaseVersion` — **never retry automatically.** An item the request names has a revision committed after its `base_version`; replaying would overwrite that edit. `errors[]` has one entry per conflicting id, up to 100, and `message` gives their total. Re-read the dataset and reconcile before writing again. * `DatasetItemCreateCollision` — **never retry unchanged.** Only `POST /evals/datasets/{dataset_id}/items` returns it: an `id` in the request is a live item with different content, or was written while this request was in flight (including by an earlier attempt of this same request). `errors[]` has one entry per colliding id, up to 100. Re-read the items: they may already hold this content. Any other value — including `Conflict`, the default every other endpoint returns — carries no retry guidance and should be treated as a plain `409`. allOf: - $ref: '#/components/schemas/ErrorResponse' DatasetItemsWriteUnavailableResponse: description: >- Error body of a `503` from a dataset item write. `errors[0].reason` is `DatasetItemsWriteUnavailable`: the data store was unavailable or too slow, and no changes were made. Retry with backoff; for a batch, send fewer items. allOf: - $ref: '#/components/schemas/ErrorResponse' DatasetVersionReference: description: >- A reference to a committed dataset version, in the spelling `?version=` accepts: the per-dataset version number. A JSON integer is accepted as well as a string and means the same version number, so `3` and `"3"` are the same reference. `true`/`false` are not. oneOf: - type: string - type: integer responses: '400': description: Bad Request content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: Forbidden content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' securitySchemes: BearerAuth: type: http scheme: bearer ````