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FDE 101

RunnableConfig

RunnableConfig is the optional configuration dictionary passed beside a Runnable’s business input. Common keys include tags, metadata, callbacks, run_name, max_concurrency, recursion_limit, and configurable.

Tiny example

Section titled “Tiny example”
config = {
    "run_name": "classify_support_ticket",
    "tags": ["support", "production"],
    "metadata": {"release": "2026.08.15"},
    "max_concurrency": 4,
}


result = chain.invoke({"ticket": "INC-104"}, config=config)

Keep the two channels distinct:

Channel Example Meaning
Input {"ticket": "INC-104"} Data the Runnable processes
Config {"tags": ["support"]} How this run executes or is observed

Failure note

Section titled “Failure note”

Tags and metadata can be inherited by child Runnables and sent to tracing systems. Do not place API keys, raw personal data, or authorization decisions in tracing metadata. The configurable field only affects attributes explicitly exposed as configurable.

Section titled “Related”

Runnables and LCEL · batch and abatch · Callbacks and tracing