docs(sdk): Remove global metrics enablement from the spec

develop-docs/sdk/telemetry/metrics.mdx

@@ -2,14 +2,17 @@
 title: Metrics
 description: Counter, gauge, and distribution metrics sent as batched trace_metric envelope items.
 spec_id: sdk/telemetry/metrics
-spec_version: 2.11.1
+spec_version: 3.0.0
 spec_status: stable
 spec_depends_on:
   - id: sdk/foundations/transport/envelopes
     version: ">=1.0.0"
   - id: sdk/foundations/state-management/scopes/attributes
     version: ">=1.0.0"
 spec_changelog:
+  - version: 3.0.0
+    date: 2026-09-28
+    summary: Removed the global metrics enablement option; retained explicit opt-in for integrations
   - version: 2.11.1
     date: 2026-09-28
     summary: Removed obsolete experimental namespace guidance and example from the stable spec
@@ -110,20 +113,19 @@ An SDK **SHOULD** implement [Tracing without Performance](/sdk/foundations/trace
 
 </Alert>
 
-<SpecSection id="processing-pipeline" status="stable" since="2.0.0">
+<SpecSection id="processing-pipeline" status="stable" since="3.0.0">
 
 ### Processing Pipeline
 
 Metric processing **MUST** follow this order:
 
 1. Capture metric via [Public APIs](#metrics-module) (e.g. `Sentry.metrics.count`).
-2. Check if metrics are disabled as per `enableMetrics`/`enable_metrics` configuration — if so, skip the rest of the steps.
-3. Pass the metric to Hub/Scope via a generic method (e.g., `captureMetric(metric)`).
-4. Pass the metric to the Client via a generic method (e.g., `captureMetric(metric)`).
-5. Process captured metric (attach default attributes as per [Default Attributes](#default-attributes)).
-6. Run `beforeSendMetric`/`before_send_metric` to filter or modify the metric.
-7. Add metric to buffer/batch processor as detailed in [Buffering](#buffering).
-8. At time of flushing buffer, send array of metrics to Sentry via `trace_metric` envelope, apply rate limiting as per [Data Category and Rate Limiting](#data-category-and-rate-limiting).
+2. Pass the metric to Hub/Scope via a generic method (e.g., `captureMetric(metric)`).
+3. Pass the metric to the Client via a generic method (e.g., `captureMetric(metric)`).
+4. Process captured metric (attach default attributes as per [Default Attributes](#default-attributes)).
+5. Run `beforeSendMetric`/`before_send_metric` to filter or modify the metric.
+6. Add metric to buffer/batch processor as detailed in [Buffering](#buffering).
+7. At time of flushing buffer, send array of metrics to Sentry via `trace_metric` envelope, apply rate limiting as per [Data Category and Rate Limiting](#data-category-and-rate-limiting).
 
 </SpecSection>
 
@@ -246,13 +248,11 @@ If `debug` is set to `true` in SDK init, calls to the Sentry metrics API **SHOUL
 
 </SpecSection>
 
-<SpecSection id="auto-emitted-metrics" status="candidate" since="2.7.0">
+<SpecSection id="auto-emitted-metrics" status="candidate" since="3.0.0">
 
 ### Auto-Emitted Metrics
 
-Metrics emitted via the [public API](#metrics-module) are opt-out. The `enableMetrics`/`enable_metrics` option **MUST** act as a general kill switch for all metrics sent to Sentry — when set to `false`, no metrics **MUST** be sent, regardless of whether they originate from the public API, auto-emitting integrations, or third-party bindings.
-
-However, metrics that are **automatically emitted by integrations or libraries** without an explicit user call follow different rules because they can generate unexpected volume and cost.
+Metrics that are **automatically emitted by integrations or libraries** without an explicit user call require opt-in because they can generate unexpected volume and cost.
 
 **Integrations that auto-emit metrics** — An SDK integration that automatically captures metrics (e.g., recording HTTP request durations, database query counts, or runtime resource usage) **MUST** be opt-in. The integration **MUST NOT** emit any metrics unless the user explicitly enables it. The opt-in mechanism **MAY** be a dedicated integration-level option or requiring the user to explicitly add the integration.
 
@@ -356,16 +356,16 @@ Each metric in the `items` array is a JSON object with the following fields:
 
 ## Public API
 
-<SpecSection id="initialization-options" status="stable" since="2.0.0">
+<SpecSection id="initialization-options" status="stable" since="3.0.0">
 
 ### Initialization Options
 
-SDKs **MUST** expose the following configuration options:
-
-- `enableMetrics`/`enable_metrics` — a boolean flag to control if metric envelopes will be generated and sent to Sentry. If `false`, the SDK **MUST NOT** send metrics. Defaults to `true`.
+SDKs **MUST** expose the following configuration option:
 
 - `beforeSendMetric`/`before_send_metric` — an **OPTIONAL** function that takes a metric object and returns a metric object. Called before sending the metric to Sentry. Can be used to modify the metric or prevent it from being sent (by returning `null`/`None`).
 
+SDKs **SHOULD NOT** provide an API whose sole purpose is to disable all metrics.
+
 </SpecSection>
 
 <SpecSection id="metrics-module" status="stable" since="2.0.0">