# User Credentials

English | [中文](credentials.zh.md)

The credential seam of [dsh-credentials](../../packages/credentials/credentials) keeps secrets out of configuration: settings sections and `cordis.yml` entries carry *references* (environment-variable names), providers such as [dsh-credentials-local](../../packages/credentials/credentials-local) own the values, and consumers resolve a reference once per operation — the LLM adapters resolve once per model request, so a rotated credential reaches the very next request without any restart. One seam-wide rule binds every provider: an empty stored value is absent everywhere.

Source: [`packages/credentials/credentials/src/index.ts`](../../packages/credentials/credentials/src/index.ts)

## Identity

A reference names one credential as a POSIX-style environment-variable name. The brand keeps references from mixing with other cross-boundary strings; construction validates the shell-identifier shape.

```ts type-equiv
/** Nominal reference to one credential: a POSIX-style environment-variable name. */
type CredentialRef = Branded<'CredentialRef'>
```

## Resolution

`resolve(ref)` returns the value with the provider-defined source layer that supplied it, or `undefined` while unconfigured. Consumers re-resolve at each operation and never cache across operations — that per-operation read is the hot-update mechanism.

```ts type-equiv
/** One resolved credential value and the source layer that supplied it. */
interface ResolvedCredential {
  /** The non-empty secret value. */
  value: string
  /** Provider-defined source layer id (the local provider uses `env` and `file`). */
  source: string
}
```

## Description

`describe(ref)` answers configuration surfaces without ever exposing a value: whether the reference resolves, from which layer, and whether `set` would currently succeed. The local provider reports a reference supplied by the live process environment as `writable: false` — a write would appear to succeed while resolution kept returning the shadowing value, so the seam rejects it and the UI can render the reference read-only up front.

```ts type-equiv
/** Source and writability facts for one reference, safe for configuration UIs — never the value. */
interface CredentialInfo {
  /** Whether {@link Credentials.resolve} would currently return a value. */
  configured: boolean
  /** Source layer currently supplying the value; absent while unconfigured. */
  source?: string
  /** Whether {@link Credentials.set} would currently succeed for this reference. */
  writable: boolean
}
```

## Change commits

`credentials/updated (ref)` fires after a committed change to a provider-managed source — a `set`, an `unset`, or an external edit observed in storage. Ambient process-environment changes are not observable and never emit. Consumers do not need the event (they re-resolve per operation); it exists for configuration surfaces refreshing a "configured" badge.
