# Package scriptorium

Import path:

```go
import "gitea.maximumdirect.net/eric/scriptorium"
```

The root package is the public Go facade for Scriptorium's prompt prepare/run
workflow. It exposes typed requests, results, source options, injected LLM
clients, and stable public errors while keeping `internal/*` packages private.

## Intended Use Cases

Use the package when a Go application needs:

- in-process prompt preparation or execution;
- typed request/result structs;
- direct `context.Context` cancellation;
- injected/fake LLM clients for tests;
- direct per-request `RunRequest.APIKey`.

Use [Subprocess integration](../integrations/subprocess.md) or the [HTTP API](../api.md)
when a process or service boundary is preferred.

## Construct An Engine

```go
engine, err := scriptorium.NewEngine(scriptorium.Config{
	PromptDir:  "./examples/prompts",
	ProfileDir: "./examples/profiles",
	SchemaDir:  "./examples/schemas",
})
if err != nil {
	return err
}
```

`Config` fields:

| Field | Description |
| --- | --- |
| `PromptDir` | Prompt definition directory. Required unless `WithPromptFS` or `WithPromptFile` is used. |
| `ProfileDir` | Optional custom profile directory overlaid above built-in profiles. |
| `SchemaDir` | Schema directory. Defaults to `.` when empty. |
| `Timeout` | Default timeout for the built-in OpenAI-compatible client. |
| `HTTPClient` | Optional HTTP client for the built-in OpenAI-compatible client. |

`NewEngine` accepts `nil` options and ignores them. Invalid construction wraps
`ErrInvalidConfig`.

## Source Options

Directory fields are the compatibility path. Explicit source options override
the matching directory field.

Prompt sources:

- `WithPromptFS(fsys, root)`
- `WithPromptFile(path)`

Profile sources:

- `WithProfileFS(fsys, root)`
- `WithProfileFile(path)`
- `WithProfiles(profiles...)`

Schema sources:

- `WithSchemaFS(fsys, root)`
- `WithSchemaFile(path)`

LLM source:

- `WithLLMClient(client)`

Source behavior:

- Prompt and profile YAML use the same strict rules as directory loading.
- Prompt `content_file` values resolve relative to the prompt file.
- `fs.FS` roots are containment boundaries for prompt content files and schema paths.
- File options expose the selected file by its base name.
- Profile source precedence is in-memory profiles, then explicit profile file/FS/directory source, then built-ins.
- `WithLLMClient(nil)` returns `ErrInvalidConfig`.

## In-Memory Profiles

Use `WithProfiles` when the application already has typed model settings:

```go
profile := scriptorium.OpenAICompatibleProfile(scriptorium.OpenAICompatibleProfileConfig{
	ID:             "app.default",
	Endpoint:       "https://openrouter.ai/api/v1",
	Model:          "mistralai/mistral-small-3.2-24b-instruct",
	APIKeyRequired: true,
})

engine, err := scriptorium.NewEngine(cfg, scriptorium.WithProfiles(profile))
```

`Profile` and `OpenAICompatibleProfileConfig` include:

- `ID`
- `Endpoint`
- `Model`
- `Temperature`
- `MaxTokens`
- `TopP`
- `TimeoutSeconds`
- `ServiceTier`
- `ReasoningEffort`
- `APIKeyRequired`
- `ExtraParams`

`WithProfiles` rejects duplicate IDs in one call. In-memory profiles do not
store raw keys. When `APIKeyRequired` is true, pass the secret on each request
with `RunRequest.APIKey`.

`ExtraParams` must be JSON-compatible: strings, booleans, finite numbers,
objects with string keys, arrays/slices, and nil. Unsupported values, non-string
map keys, non-finite floats, and cycles return `ErrInvalidConfig` for profiles
or `ErrInvalidRequest` for request overrides.

## Prepare Workflow

`Prepare` resolves prompt/profile/input/schema state and renders messages
without calling an LLM.

```go
prepared, err := engine.Prepare(ctx, scriptorium.RunRequest{
	PromptID: "generic.markdown_summary",
	Inputs: map[string]scriptorium.ArtifactRef{
		"transcript": scriptorium.File("./examples/fixtures/transcript.md"),
		"glossary":   scriptorium.File("./examples/fixtures/glossary.yml"),
	},
})
if err != nil {
	return err
}
_ = prepared.EffectiveModelParams
```

`PreparedRun` includes prompt ID/version/hash, selected profile, effective
model params, output contract, structured-output metadata, input hashes,
rendered prompt hash, rendered messages, and timing fields. It does not include
raw API-key values, model output, validation results, or internal target
presence metadata.

## Run Workflow

`Run` calls `Prepare`, invokes the configured LLM client, builds the output
artifact, and validates the output.

```go
result, err := engine.Run(ctx, scriptorium.RunRequest{
	PromptID: "generic.markdown_summary",
	APIKey:   apiKey,
	Inputs: map[string]scriptorium.ArtifactRef{
		"transcript": scriptorium.File("./examples/fixtures/transcript.md"),
		"glossary":   scriptorium.File("./examples/fixtures/glossary.yml"),
	},
})
if err != nil {
	return err
}
_ = result.Artifact
```

`RunResult` includes run ID, output artifact, raw output, validation result,
prompt/profile/model metadata, effective model params, input hashes, usage, and
timing fields.

Generated-content validation failures return a successful `RunResult` with
`Validation.Status == ValidationFailed`. Runtime/schema validation errors
return an error that matches `ErrValidation`.

## Inputs

Input helpers:

- `File(path)`: file-backed artifact reference.
- `Inline(body)`: inline artifact body.
- `InlineWithURI(uri, body)`: inline artifact body with URI metadata.

Input map keys must match the prompt's expected input names.

## Injected LLM Clients

Use `WithLLMClient` for tests or custom model integrations:

```go
type fakeLLM struct{}

func (fakeLLM) Generate(ctx context.Context, req scriptorium.GenerateRequest) (*scriptorium.GenerateResponse, error) {
	return &scriptorium.GenerateResponse{
		Content: "generated text",
		Usage:   scriptorium.TokenUsage{TotalTokens: 12},
	}, nil
}

engine, err := scriptorium.NewEngine(cfg, scriptorium.WithLLMClient(fakeLLM{}))
```

Injected clients receive:

- rendered prompt;
- effective execution target;
- numeric target presence metadata;
- structured-output spec when applicable;
- direct request API key when provided.

Custom clients should not log raw prompts or API keys by default.

## Overrides And API Keys

`RunRequest` fields:

| Field | Description |
| --- | --- |
| `PromptID` | Prompt ID. |
| `PromptVersion` | Optional prompt version filter. |
| `ProfileID` | Optional profile override. |
| `APIKey` | Direct per-request API key. |
| `Inputs` | Input artifact references. |
| `Vars` | Template variables. |
| `Execution` | Per-request model overrides. |
| `Validation` | Per-request output contract override. |
| `Metadata` | Request metadata reserved for callers. |

`RunRequest.Execution` uses pointer fields for numeric values so explicit zero
overrides are preserved:

```go
zero := 0
req.Execution = &scriptorium.ExecutionTargetOverride{
	MaxTokens: &zero,
}
```

Direct `RunRequest.APIKey` takes precedence over profile `api_key_env` for the
default OpenAI-compatible client. It is request-scoped, uses `json:"-"`, and is
not included in `PreparedRun` or `RunResult` JSON. Normal Go string formatting
of `RunRequest` and `GenerateRequest` reports only whether a direct key is set.

Raw API keys do not belong in profile YAML, in-memory profiles, or app config.
Avoid reflection-based debug dumps of request structs because exported fields
remain visible to tools that bypass `String` and `GoString`.

## Errors

Public methods wrap context while preserving stable sentinel checks with
`errors.Is`:

- `ErrInvalidConfig`
- `ErrInvalidRequest`
- `ErrPromptNotFound`
- `ErrProfileNotFound`
- `ErrPromptLoad`
- `ErrProfileLoad`
- `ErrArtifactLoad`
- `ErrPromptRender`
- `ErrLLMGenerate`
- `ErrValidation`

Example:

```go
if errors.Is(err, scriptorium.ErrPromptNotFound) {
	return err
}
```

## Examples

Run the maintained prepare-only example from the repository root:

```bash
go run ./examples/go-library/prepare
```

See also:

- [Configuration reference](../config.md)
- [Consumer integration overview](api.md)