> ## Documentation Index > Fetch the complete documentation index at: https://docs.wandb.ai/llms.txt > Use this file to discover all available pages before exploring further. # Configure Weave environment variables > Configure Weave's behavior at runtime using environment variables Weave provides a set of environment variables to configure and optimize its behavior. You can set these variables in your shell or within scripts to control specific functionality. ```bash theme={null} # Example of setting environment variables in the shell export WEAVE_PARALLELISM=10 # Controls the number of parallel workers export WEAVE_PRINT_CALL_LINK=false # Disables call link output ``` ```python lines theme={null} # Example of setting environment variables in Python import os os.environ["WEAVE_PARALLELISM"] = "10" os.environ["WEAVE_PRINT_CALL_LINK"] = "false" ``` ## Available environment variables | Variable | Type | Default | Description | | ------------------------------- | -------- | ------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `WANDB_API_KEY` | `string` | `None` | If set, automatically log into W\&B Weave without being prompted for your API key. To generate an API key, log in to your W\&B account and go to [User Settings](https://wandb.ai/settings). | | `WEAVE_DISABLED` | `bool` | `false` | When set to `true`, disables all Weave tracing. Weave ops will behave like regular functions. | | `WEAVE_PRINT_CALL_LINK` | `bool` | `true` | Controls whether to print a link to the Weave UI when calling a Weave op. You can also set this directly in your code by configuring the `settings` argument for `weave.init()` like this: `weave.init("your-project-name", settings={"print_call_link": False})` | | `WEAVE_LOG_LEVEL` | `str` | `INFO` | Controls the log level of the weave logger. | | `WEAVE_CAPTURE_CODE` | `bool` | `true` | Controls whether to save code for ops so they can be reloaded for later use. | | `WEAVE_DEBUG_HTTP` | `bool` | `false` | When set to `true`, turns on HTTP request and response logging for debugging. | | `WEAVE_PARALLELISM` | `int` | `20` | In evaluations, controls the number of examples to evaluate in parallel. Set to `1` to run examples sequentially. | | `WEAVE_TRACE_LANGCHAIN` | `bool` | `true` | Controls global tracing for LangChain. Set to `false` to explicitly disable LangChain tracing. | | `WEAVE_USE_SERVER_CACHE` | `bool` | `true` | Enables server response caching. When enabled, responses from the server are cached to disk to improve performance for repeated queries. | | `WEAVE_SERVER_CACHE_SIZE_LIMIT` | `int` | `1000000000` | Sets the maximum size limit for the server cache in bytes. When the cache reaches this size, older entries are automatically removed to make space for new ones. Important: the underlying implementation uses SQLite which has a Write-Ahead Log (WAL) that will grow to 4MB regardless of this setting. This WAL will be removed when the program exits. | | `WEAVE_SERVER_CACHE_DIR` | `str` | `None` | Specifies the directory where cache files should be stored. If not set, a temporary directory is used. | | `WEAVE_MAX_CALLS_QUEUE_SIZE` | `int` | `100000` | Sets the maximum size of the calls queue. Defaults to 100\_000. Setting a value of 0 means the queue can grow unbounded. | | `WEAVE_ENABLE_WAL` | `bool` | `false` | Enable the Weave [Write-Ahead Log (WAL)](/weave/guides/tracking/write-ahead-log). When set to `true`, Weave API requests are written to disk before being sent to the server, improving resilience against data loss. | | `WEAVE_DISABLE_WAL_SENDER` | `bool` | `false` | Disable the WEAVE write-ahead log sender. When set to `true`, Weave requests are written to disk but not flushed to the server. Useful for debugging. | | `WEAVE_RETRY_MAX_ATTEMPTS` | `int` | `3` | Sets the maximum number of retry attempts for failed requests. | | `WEAVE_RETRY_MAX_INTERVAL` | `float` | `300.0` | Sets the maximum interval between retry attempts in seconds. | | `WANDB_BASE_URL` | `string` | `None` | Sets the Weave host URL. Equivalent to entering the host URL when prompted by `wandb.login()`. You can specify `WANDB_BASE_URL` and `WANDB_API_KEY` before using `weave.init()` to automatically log into and authenticate to Weave. | All boolean environment variables accept the following values (case-insensitive): * `true`, `1`, `yes`, `on` for True * `false`, `0`, `no`, `off` for False