# `Sigra.Application`
[🔗](https://github.com/sztheory/sigra/blob/v1.20.0/lib/sigra/application.ex#L1)

OTP application callback for Sigra.

Sigra itself does not start any long-lived processes — it is a library
whose security primitives run inline in the host application. This
callback exists so that one-shot startup diagnostics (configuration
checks, missing optional-dep warnings) can run when the host app boots.

Today it performs a single boot-time check: if the host has configured
`config :sigra, :audit, retention_days: N` but does not have Oban in the
dep tree, log a warning advising the inline fallback path
(`Sigra.Audit.cleanup/1`). See Phase 9 decisions D-09, D-10, D-36.

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*Consult [api-reference.md](api-reference.md) for complete listing*