Environment variables

ModusBrain prefers MODUSBRAIN_* environment variables. Legacy MODUSBRAIN_* names still work.

Home and config

Variable	Description
`MODUSBRAIN_HOME`	Parent directory for config (appends `/.modusbrain`)
`GBRAIN_HOME`	Legacy alias for `MODUSBRAIN_HOME`

Variable	Description
`MODUSBRAIN_DATABASE_URL`	Postgres connection URL
`GBRAIN_DATABASE_URL`	Legacy alias

Variable	Description
`MODUSBRAIN_SOURCE`	Default source ID for CLI/MCP
`GBRAIN_SOURCE`	Legacy alias

Dotfile: .modusbrain-source (legacy .gbrain-source also read)

Variable	Description
`ANTHROPIC_API_KEY`	For synthesis (`modusbrain think`)
`OPENAI_API_KEY`	Embeddings (optional)
`MODUSBRAIN_EMBEDDING_MODEL`	Override embedding model
`MODUSBRAIN_CHAT_MODEL`	Override chat model

export MODUSBRAIN_HOME=$HOME
export MODUSBRAIN_SOURCE=default
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