diff --git a/.chloggen/ff-value-body-attribute.yaml b/.chloggen/ff-value-body-attribute.yaml
new file mode 100755
index 0000000000..3314b576c6
--- /dev/null
+++ b/.chloggen/ff-value-body-attribute.yaml
@@ -0,0 +1,22 @@
+# Use this changelog template to create an entry for release notes.
+#
+# If your change doesn't affect end users you should instead start
+# your pull request title with [chore] or use the "Skip Changelog" label.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the area of concern in the attributes-registry, (e.g. http, cloud, db)
+component: feature_flag
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Move the evaluated value from the event body to attributes
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+# The values here must be integers.
+issues: [1990]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
diff --git a/docs/attributes-registry/feature-flag.md b/docs/attributes-registry/feature-flag.md
index 803cb30796..7ee30b6f17 100644
--- a/docs/attributes-registry/feature-flag.md
+++ b/docs/attributes-registry/feature-flag.md
@@ -14,11 +14,19 @@ This document defines attributes for Feature Flags.
| `feature_flag.evaluation.reason` | string | The reason code which shows how a feature flag value was determined. | `static`; `targeting_match`; `error`; `default` |  |
| `feature_flag.key` | string | The lookup key of the feature flag. | `logo-color` |  |
| `feature_flag.provider_name` | string | Identifies the feature flag provider. | `Flag Manager` |  |
+| `feature_flag.result.type` | string | The JSON type of the `feature_flag.result.value`. | `string`; `boolean`; `number` |  |
+| `feature_flag.result.value` | string | The evaluated value of the feature flag represented as a JSON string. [1] | `#ff0000`; `1`; `true` |  |
| `feature_flag.set.id` | string | The identifier of the [flag set](https://openfeature.dev/specification/glossary/#flag-set) to which the feature flag belongs. | `proj-1`; `ab98sgs`; `service1/dev` |  |
-| `feature_flag.variant` | string | A semantic identifier for an evaluated flag value. [1] | `red`; `true`; `on` |  |
+| `feature_flag.variant` | string | A semantic identifier for an evaluated flag value. [2] | `red`; `true`; `on` |  |
| `feature_flag.version` | string | The version of the ruleset used during the evaluation. This may be any stable value which uniquely identifies the ruleset. | `1`; `01ABCDEF` |  |
-**[1] `feature_flag.variant`:** A semantic identifier, commonly referred to as a variant, provides a means
+**[1] `feature_flag.result.value`:** With some feature flag providers, feature flag results can be quite large or contain private or sensitive details.
+Because of this, `feature_flag.result.variant` is often the preferred attribute if it is available.
+
+It may be desirable to redact or otherwise limit the size and scope of `feature_flag.result.value` if possible.
+Because the evaluated flag value is unstructured and may be any type, it left to the instrumentation author to determine how best to achieve this.
+
+**[2] `feature_flag.variant`:** A semantic identifier, commonly referred to as a variant, provides a means
for referring to a value without including the value itself. This can
provide additional context for understanding the meaning behind a value.
For example, the variant `red` maybe be used for the value `#c05543`.
@@ -38,3 +46,15 @@ For example, the variant `red` maybe be used for the value `#c05543`.
| `static` | The resolved value is static (no dynamic evaluation). |  |
| `targeting_match` | The resolved value was the result of a dynamic evaluation, such as a rule or specific user-targeting. |  |
| `unknown` | The reason for the resolved value could not be determined. |  |
+
+---
+
+`feature_flag.result.type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
+
+| Value | Description | Stability |
+|---|---|---|
+| `array` | The `feature_flag.result.value` is a stringified array. |  |
+| `boolean` | The `feature_flag.result.value` is a stringified boolean. |  |
+| `number` | The `feature_flag.result.value` is a stringified number. |  |
+| `object` | The `feature_flag.result.value` is a stringified object. |  |
+| `string` | The `feature_flag.result.value` is a string. |  |
diff --git a/docs/feature-flags/feature-flags-logs.md b/docs/feature-flags/feature-flags-logs.md
index 80b7c5525d..04c2d9c337 100644
--- a/docs/feature-flags/feature-flags-logs.md
+++ b/docs/feature-flags/feature-flags-logs.md
@@ -60,9 +60,11 @@ A `feature_flag.evaluation` event SHOULD be emitted whenever a feature flag valu
|---|---|---|---|---|---|
| [`feature_flag.key`](/docs/attributes-registry/feature-flag.md) | string | The lookup key of the feature flag. | `logo-color` | `Required` |  |
| [`error.type`](/docs/attributes-registry/error.md) | string | Describes a class of error the operation ended with. [1] | `provider_not_ready`; `targeting_key_missing`; `provider_fatal`; `general` | `Conditionally Required` [2] |  |
-| [`feature_flag.variant`](/docs/attributes-registry/feature-flag.md) | string | A semantic identifier for an evaluated flag value. [3] | `red`; `true`; `on` | `Conditionally Required` [4] |  |
+| [`feature_flag.result.type`](/docs/attributes-registry/feature-flag.md) | string | The JSON type of the `feature_flag.result.value`. | `string`; `boolean`; `number` | `Conditionally Required` [3] |  |
+| [`feature_flag.result.value`](/docs/attributes-registry/feature-flag.md) | string | The evaluated value of the feature flag represented as a JSON string. [4] | `#ff0000`; `1`; `true` | `Conditionally Required` [5] |  |
+| [`feature_flag.variant`](/docs/attributes-registry/feature-flag.md) | string | A semantic identifier for an evaluated flag value. [6] | `red`; `true`; `on` | `Conditionally Required` [7] |  |
| [`feature_flag.context.id`](/docs/attributes-registry/feature-flag.md) | string | The unique identifier for the flag evaluation context. For example, the targeting key. | `5157782b-2203-4c80-a857-dbbd5e7761db` | `Recommended` |  |
-| [`feature_flag.evaluation.error.message`](/docs/attributes-registry/feature-flag.md) | string | A message explaining the nature of an error occurring during flag evaluation. | `Flag `header-color` expected type `string` but found type `number`` | `Recommended` [5] |  |
+| [`feature_flag.evaluation.error.message`](/docs/attributes-registry/feature-flag.md) | string | A message explaining the nature of an error occurring during flag evaluation. | `Flag `header-color` expected type `string` but found type `number`` | `Recommended` [8] |  |
| [`feature_flag.evaluation.reason`](/docs/attributes-registry/feature-flag.md) | string | The reason code which shows how a feature flag value was determined. | `static`; `targeting_match`; `error`; `default` | `Recommended` |  |
| [`feature_flag.provider_name`](/docs/attributes-registry/feature-flag.md) | string | Identifies the feature flag provider. | `Flag Manager` | `Recommended` |  |
| [`feature_flag.set.id`](/docs/attributes-registry/feature-flag.md) | string | The identifier of the [flag set](https://openfeature.dev/specification/glossary/#flag-set) to which the feature flag belongs. | `proj-1`; `ab98sgs`; `service1/dev` | `Recommended` |  |
@@ -83,14 +85,24 @@ A `feature_flag.evaluation` event SHOULD be emitted whenever a feature flag valu
**[2] `error.type`:** If and only if an error occurred during flag evaluation.
-**[3] `feature_flag.variant`:** A semantic identifier, commonly referred to as a variant, provides a means
+**[3] `feature_flag.result.type`:** If and only if `feature_flag.result.value` is set.
+
+**[4] `feature_flag.result.value`:** With some feature flag providers, feature flag results can be quite large or contain private or sensitive details.
+Because of this, `feature_flag.result.variant` is often the preferred attribute if it is available.
+
+It may be desirable to redact or otherwise limit the size and scope of `feature_flag.result.value` if possible.
+Because the evaluated flag value is unstructured and may be any type, it left to the instrumentation author to determine how best to achieve this.
+
+**[5] `feature_flag.result.value`:** If and only if feature flag provider does not supply variant or equivalent concept. Otherwise, `feature_flag.result.value` should be treated as opt-in.
+
+**[6] `feature_flag.variant`:** A semantic identifier, commonly referred to as a variant, provides a means
for referring to a value without including the value itself. This can
provide additional context for understanding the meaning behind a value.
For example, the variant `red` maybe be used for the value `#c05543`.
-**[4] `feature_flag.variant`:** If feature flag provider supplies a variant or equivalent concept.
+**[7] `feature_flag.variant`:** If feature flag provider supplies a variant or equivalent concept.
-**[5] `feature_flag.evaluation.error.message`:** If and only if an error occurred. It's NOT RECOMMENDED to duplicate the value of `error.type` in `feature_flag.evaluation.error.message`.
+**[8] `feature_flag.evaluation.error.message`:** If and only if an error occurred. It's NOT RECOMMENDED to duplicate the value of `error.type` in `feature_flag.evaluation.error.message`.
---
@@ -116,13 +128,17 @@ For example, the variant `red` maybe be used for the value `#c05543`.
| `targeting_match` | The resolved value was the result of a dynamic evaluation, such as a rule or specific user-targeting. |  |
| `unknown` | The reason for the resolved value could not be determined. |  |
-**Body fields:**
+---
-| Body Field | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability |
-|---|---|---|---|---|---|
-| `value` | undefined | The evaluated value of the feature flag. | `#ff0000`; `1`; `true` | `Conditionally Required` [1] |  |
+`feature_flag.result.type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
-**[1] `value`:** If and only if feature flag provider does not supply variant or equivalent concept. Otherwise, `value` should be treated as opt-in.
+| Value | Description | Stability |
+|---|---|---|
+| `array` | The `feature_flag.result.value` is a stringified array. |  |
+| `boolean` | The `feature_flag.result.value` is a stringified boolean. |  |
+| `number` | The `feature_flag.result.value` is a stringified number. |  |
+| `object` | The `feature_flag.result.value` is a stringified object. |  |
+| `string` | The `feature_flag.result.value` is a string. |  |
diff --git a/model/feature-flags/logs.yaml b/model/feature-flags/logs.yaml
index fa5429af50..a851f1e613 100644
--- a/model/feature-flags/logs.yaml
+++ b/model/feature-flags/logs.yaml
@@ -18,6 +18,15 @@ groups:
- ref: feature_flag.variant
requirement_level:
conditionally_required: If feature flag provider supplies a variant or equivalent concept.
+ - ref: feature_flag.result.value
+ requirement_level:
+ conditionally_required: >
+ If and only if feature flag provider does not supply variant or equivalent concept.
+ Otherwise, `feature_flag.result.value` should be treated as opt-in.
+ - ref: feature_flag.result.type
+ requirement_level:
+ conditionally_required: >
+ If and only if `feature_flag.result.value` is set.
- ref: feature_flag.provider_name
requirement_level: recommended
- ref: feature_flag.context.id
@@ -49,18 +58,3 @@ groups:
- ref: feature_flag.evaluation.error.message
requirement_level:
recommended: If and only if an error occurred. It's NOT RECOMMENDED to duplicate the value of `error.type` in `feature_flag.evaluation.error.message`.
- body:
- id: feature_flag.evaluation
- type: map
- requirement_level: recommended
- stability: development
- fields:
- - id: value
- type: undefined
- stability: development
- brief: The evaluated value of the feature flag.
- requirement_level:
- conditionally_required: >
- If and only if feature flag provider does not supply variant or equivalent concept.
- Otherwise, `value` should be treated as opt-in.
- examples: ["#ff0000", "1", "true"]
diff --git a/model/feature-flags/registry.yaml b/model/feature-flags/registry.yaml
index 264d6945be..fe845211a7 100644
--- a/model/feature-flags/registry.yaml
+++ b/model/feature-flags/registry.yaml
@@ -93,3 +93,40 @@ groups:
stability: development
examples: ["Flag `header-color` expected type `string` but found type `number`"]
brief: A message explaining the nature of an error occurring during flag evaluation.
+ - id: feature_flag.result.value
+ type: string
+ stability: development
+ examples: ["#ff0000", "1", "true"]
+ brief: The evaluated value of the feature flag represented as a JSON string.
+ note: |
+ With some feature flag providers, feature flag results can be quite large or contain private or sensitive details.
+ Because of this, `feature_flag.result.variant` is often the preferred attribute if it is available.
+
+ It may be desirable to redact or otherwise limit the size and scope of `feature_flag.result.value` if possible.
+ Because the evaluated flag value is unstructured and may be any type, it left to the instrumentation author to determine how best to achieve this.
+ - id: feature_flag.result.type
+ type:
+ members:
+ - id: string
+ value: "string"
+ brief: The `feature_flag.result.value` is a string.
+ stability: development
+ - id: number
+ value: "number"
+ brief: The `feature_flag.result.value` is a stringified number.
+ stability: development
+ - id: boolean
+ value: "boolean"
+ brief: The `feature_flag.result.value` is a stringified boolean.
+ stability: development
+ - id: object
+ value: "object"
+ brief: The `feature_flag.result.value` is a stringified object.
+ stability: development
+ - id: array
+ value: "array"
+ brief: The `feature_flag.result.value` is a stringified array.
+ stability: development
+ stability: development
+ examples: ["string", "boolean", "number"]
+ brief: The JSON type of the `feature_flag.result.value`.