feat: Add @flue/runtime instrumentation

.agents/skills/e2e-tests/SKILL.md

@@ -64,6 +64,7 @@ Cassettes mock provider HTTP responses (OpenAI, Anthropic, ...) so external-prov
 - When a scenario family already has `assertions.ts`, keep version- or provider-specific test setup in `scenario.test.ts` and reuse the shared assertions file.
 - Keep the CI e2e summary up to date. If a scenario version matrix or `variantKey` changes, update `e2e/config/pr-comment-scenarios.json` in the same change and follow the established pattern used by other versioned scenarios: one summary row per version, not separate wrapped/auto rows unless that pattern already exists for the scenario family.
 - Run new or updated scenarios three times in a row before considering snapshots stable.
+- Do not add tests directly asserting on the auto instrumentation configs.
 
 ## Scenario Patterns
 

.changeset/clear-months-fold.md

@@ -0,0 +1,5 @@
+---
+"braintrust": minor
+---
+
+feat: Add `@flue/runtime` instrumentation

e2e/config/pr-comment-scenarios.json

@@ -162,6 +162,18 @@
     "metadataScenario": "cursor-sdk-instrumentation",
     "variants": [{ "variantKey": "cursor-sdk-v1", "label": "v1" }]
   },
+  {
+    "scenarioDirName": "flue-instrumentation",
+    "label": "Flue Instrumentation",
+    "metadataScenario": "flue-instrumentation",
+    "variants": [
+      { "variantKey": "flue-v0-7-0-wrapped", "label": "v0.7.0 wrapped" },
+      {
+        "variantKey": "flue-v0-7-0-auto-hook",
+        "label": "v0.7.0 auto-hook"
+      }
+    ]
+  },
   {
     "scenarioDirName": "github-copilot-instrumentation",
     "label": "GitHub Copilot SDK Instrumentation",

e2e/scenarios/flue-instrumentation/.agents/skills/e2e-flue-skill/SKILL.md

@@ -0,0 +1,6 @@
+---
+name: e2e-flue-skill
+description: Deterministic skill used by the Braintrust Flue instrumentation e2e test.
+---
+
+Return the marker from the provided args exactly once. Output no other text.