Do not infer for strict mode.

cli/internal/taskhash/taskhash.go

@@ -380,17 +380,30 @@ func (th *Tracker) CalculateTaskHash(packageTask *nodes.PackageTask, dependencyS
 	}
 
 	var keyMatchers []string
-	framework := inference.InferFramework(packageTask.Pkg)
-	if framework != nil && framework.EnvMatcher != "" {
-		// log auto detected framework and env prefix
-		logger.Debug(fmt.Sprintf("auto detected framework for %s", packageTask.PackageName), "framework", framework.Slug, "env_prefix", framework.EnvMatcher)
-		keyMatchers = append(keyMatchers, framework.EnvMatcher)
+	var framework *inference.Framework
+	envVarContainingExcludePrefix := ""
+
+	// In strict environment variable mode we don't do framework env var inference.
+	// You must instead:
+	// - Specify all environment variables that you want available in your build environment.
+	// - Specify whether you want those considered for the hash or merely passed through.
+	//
+	// This allows advanced users to improve both cache hit ratio _and_ correctness with
+	// the tradeoff of increased configuration verbosity.
+	if packageTask.EnvMode != util.Strict {
+		envVarContainingExcludePrefix = "TURBO_CI_VENDOR_ENV_KEY"
+		framework := inference.InferFramework(packageTask.Pkg)
+		if framework != nil && framework.EnvMatcher != "" {
+			// log auto detected framework and env prefix
+			logger.Debug(fmt.Sprintf("auto detected framework for %s", packageTask.PackageName), "framework", framework.Slug, "env_prefix", framework.EnvMatcher)
+			keyMatchers = append(keyMatchers, framework.EnvMatcher)
+		}
 	}
 
 	envVars, err := env.GetHashableEnvVars(
 		packageTask.TaskDefinition.EnvVarDependencies,
 		keyMatchers,
-		"TURBO_CI_VENDOR_ENV_KEY",
+		envVarContainingExcludePrefix,
 	)
 	if err != nil {
 		return "", err

docs/pages/repo/docs/core-concepts/caching.mdx

@@ -261,6 +261,13 @@ To alter the cache for _all_ tasks, you can declare environment variables in the
 
 ### Automatic environment variable inclusion
 
+<Callout type="warning">
+  Turborepo only does automatic environment variable inclusion when the environment variable mode is set to `loose` or when using the default environment variable mode of `infer` without specifying `passthroughEnv`.
+
+In `strict` environment variable mode you must specify every environment variable you want available in your execution environment via `env` or `globalEnv` if you want them considered for the hash and `passthroughEnv` or `globalPassthroughEnv` if not.
+
+</Callout>
+
 To help ensure correct caching across environments, Turborepo automatically infers and includes public environment variables when calculating cache keys for apps built with detected frameworks. You can safely omit framework-specific public environment variables from `turbo.json`:
 
 ```diff filename="turbo.json"