chore: Set default values for optional LaunchDarkly keys in example env files

Python's os.getenv(key, default) returns the default only when the var
is unset. dotenv loads `KEY=` as a *set* empty string, so a user who
copies `.env.example` to `.env` without editing would silently get an
empty string and the AI Config lookup would fail.

Setting the documented defaults inline (e.g. LAUNCHDARKLY_COMPLETION_KEY=
sample-completion) fixes that and removes the duplicate "defaults to X"
comments. Required vars (SDK key, provider keys) stay blank.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: jsonbailey

features/create_agent/.env.example

@@ -4,5 +4,5 @@ LAUNCHDARKLY_SDK_KEY=
 # Provider API key(s) for the provider your agent config uses
 OPENAI_API_KEY=
 
-# Optional - defaults to "sample-agent"
-LAUNCHDARKLY_AGENT_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_AGENT_KEY=sample-agent

features/create_agent_graph/.env.example

@@ -4,5 +4,5 @@ LAUNCHDARKLY_SDK_KEY=
 # Provider API key(s) for the provider(s) your agent graph uses
 OPENAI_API_KEY=
 
-# Optional - defaults to "sample-agent-graph"
-LAUNCHDARKLY_AGENT_GRAPH_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_AGENT_GRAPH_KEY=sample-agent-graph

features/create_judge/.env.example

@@ -4,5 +4,5 @@ LAUNCHDARKLY_SDK_KEY=
 # Provider API key(s) for the provider your judge config uses
 OPENAI_API_KEY=
 
-# Optional - defaults to "sample-judge"
-LAUNCHDARKLY_JUDGE_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_JUDGE_KEY=sample-judge

features/create_model/.env.example

@@ -4,5 +4,5 @@ LAUNCHDARKLY_SDK_KEY=
 # Provider API key(s) for the provider your AI config uses
 OPENAI_API_KEY=
 
-# Optional - defaults to "sample-completion"
-LAUNCHDARKLY_COMPLETION_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_COMPLETION_KEY=sample-completion

getting_started/bedrock/converse/.env.example

@@ -8,5 +8,5 @@ AWS_SECRET_ACCESS_KEY=
 # Optional - defaults to "us-east-1"
 AWS_DEFAULT_REGION=
 
-# Optional - defaults to "sample-completion"
-LAUNCHDARKLY_COMPLETION_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_COMPLETION_KEY=sample-completion

getting_started/gemini/generate_content/.env.example

@@ -4,5 +4,5 @@ LAUNCHDARKLY_SDK_KEY=
 # Your Google API key
 GOOGLE_API_KEY=
 
-# Optional - defaults to "sample-completion"
-LAUNCHDARKLY_COMPLETION_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_COMPLETION_KEY=sample-completion

getting_started/langchain/invoke/.env.example

@@ -7,5 +7,5 @@ GOOGLE_API_KEY=
 AWS_ACCESS_KEY_ID=
 AWS_SECRET_ACCESS_KEY=
 
-# Optional - defaults to "sample-completion"
-LAUNCHDARKLY_COMPLETION_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_COMPLETION_KEY=sample-completion

getting_started/langgraph/react_agent/.env.example

@@ -7,5 +7,5 @@ GOOGLE_API_KEY=
 AWS_ACCESS_KEY_ID=
 AWS_SECRET_ACCESS_KEY=
 
-# Optional - defaults to "sample-agent"
-LAUNCHDARKLY_AGENT_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_AGENT_KEY=sample-agent

getting_started/langgraph/state_graph/.env.example

@@ -7,8 +7,8 @@ GOOGLE_API_KEY=
 AWS_ACCESS_KEY_ID=
 AWS_SECRET_ACCESS_KEY=
 
-# Optional - defaults to "code-review-analyzer"
-LAUNCHDARKLY_ANALYZER_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_ANALYZER_KEY=code-review-analyzer
 
-# Optional - defaults to "code-review-documentation"
-LAUNCHDARKLY_DOCUMENTATION_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_DOCUMENTATION_KEY=code-review-documentation

getting_started/openai/chat_completions/.env.example

@@ -4,5 +4,5 @@ LAUNCHDARKLY_SDK_KEY=
 # Your OpenAI API key
 OPENAI_API_KEY=
 
-# Optional - defaults to "sample-completion"
-LAUNCHDARKLY_COMPLETION_KEY=
+# Override to use a different AI Config
+LAUNCHDARKLY_COMPLETION_KEY=sample-completion