Documentation
¶
Overview ¶
Package chat defines the serializable provider-neutral chat protocol and its minimal synchronous Model and optional Streamer capabilities.
Construct messages and requests with NewSystemMessage, NewUserMessage, and NewRequest. Leaf constructors establish protocol shape; aggregate roots and model boundaries validate the complete value. Call Validate again after mutating exported fields. System messages form a leading prefix so providers with a distinct system channel can translate a request without reordering it. Options express only per-call overrides; ToolChoice describes portable tool selection, ReasoningEffort carries model-advertised intensity without imposing one provider's closed enum, and OutputFormat describes the requested representation without adopting provider wire naming. Namespaced Extensions preserve provider data without expanding the shared protocol for every provider feature.
Response is a complete, stable output. Streamer yields ResponseDelta transport increments instead of partial Responses; ResponseAccumulator is the single promotion path between them and requires a terminal finish reason. Citations, refusals, reasoning replay state, and tool calls remain typed protocol values while exact provider-only data stays in namespaced metadata.
ToolDefinition describes wire schema only. Executable tools, registries, history, retries, middleware policy, and tool loops belong to higher-level modules. Protocol values therefore never retain callbacks, provider clients, or other runtime objects.
Example ¶
package main
import (
"fmt"
"github.com/Tangerg/scope/core/chat"
)
func main() {
request, err := chat.NewRequest(
chat.NewSystemMessage("Answer concisely."),
chat.NewUserMessage(chat.NewTextPart("What is a scope?")),
)
if err != nil {
panic(err)
}
request.Options = chat.Options{Model: "provider-model"}
fmt.Println(request.Messages[1].Text())
fmt.Println(request.Options.Model)
}
Output: What is a scope? provider-model
Index ¶
- Variables
- type CallMiddleware
- type Citation
- type CitationSource
- type CitationSourceKind
- type FinishReason
- type JSONSchemaConfig
- type Message
- type Model
- type ModelFunc
- type Options
- type Output
- type OutputFormat
- type OutputFormatType
- type OutputMetadata
- type Part
- type PartDelta
- type PartDeltaKind
- type PartKind
- type ReasoningEffort
- type Request
- type Response
- type ResponseAccumulator
- type ResponseDelta
- type ResponseMetadata
- type Role
- type StreamMiddleware
- type Streamer
- type StreamerFunc
- type ToolCall
- type ToolCallDelta
- type ToolChoice
- type ToolChoiceMode
- type ToolDefinition
- type ToolOutput
- type ToolParallelism
- type ToolResult
- type Usage
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrInvalidMessage = errors.New("chat: invalid message") ErrInvalidPart = errors.New("chat: invalid part") ErrInvalidToolCall = errors.New("chat: invalid tool call") ErrInvalidToolOutput = errors.New("chat: invalid tool output") ErrInvalidToolResult = errors.New("chat: invalid tool result") )
var ( ErrInvalidOutputFormat = errors.New("chat: invalid output format") ErrUnsupportedOutputFormat = errors.New("chat: unsupported output format") )
var ErrInvalidCitation = errors.New("chat: invalid citation")
var ErrInvalidOptions = errors.New("chat: invalid options")
var ErrInvalidRequest = errors.New("chat: invalid request")
var ErrInvalidResponse = errors.New("chat: invalid response")
var ErrInvalidToolChoice = errors.New("chat: invalid tool choice")
var ErrInvalidToolDefinition = errors.New("chat: invalid tool definition")
var ErrInvalidUsage = errors.New("chat: invalid usage")
Functions ¶
This section is empty.
Types ¶
type CallMiddleware ¶
CallMiddleware wraps a Model with cross-cutting call behavior. Concrete logging, tracing, retry, history, and safety policy belong to upper modules; core/chat only owns this composition vocabulary.
type Citation ¶ added in v0.13.0
type Citation struct {
Source CitationSource `json:"source"`
Title string `json:"title,omitempty"`
Quote string `json:"quote,omitempty"`
}
Citation is the portable identity and quoted evidence attached to a text part. Exact provider coordinates remain available through response metadata.
type CitationSource ¶ added in v0.13.0
type CitationSource struct {
Kind CitationSourceKind `json:"kind"`
Value string `json:"value"`
}
CitationSource identifies cited material without adopting a provider's location taxonomy. Provider-native page, block, and character coordinates remain in the preserved native response.
func (CitationSource) Validate ¶ added in v0.13.0
func (c CitationSource) Validate() error
type CitationSourceKind ¶ added in v0.13.0
type CitationSourceKind string
const ( CitationSourceURI CitationSourceKind = "uri" CitationSourceReference CitationSourceKind = "reference" )
func (CitationSourceKind) Valid ¶ added in v0.13.0
func (c CitationSourceKind) Valid() bool
type FinishReason ¶
type FinishReason string
FinishReason explains why generation stopped. Complete outputs require a non-empty value; ResponseDelta uses the empty value before termination.
const ( FinishReasonStop FinishReason = "stop" FinishReasonLength FinishReason = "length" FinishReasonToolCalls FinishReason = "tool_calls" FinishReasonContentFilter FinishReason = "content_filter" FinishReasonRefusal FinishReason = "refusal" FinishReasonOther FinishReason = "other" )
func (FinishReason) String ¶
func (f FinishReason) String() string
func (FinishReason) Valid ¶
func (f FinishReason) Valid() bool
type JSONSchemaConfig ¶ added in v0.13.0
type JSONSchemaConfig struct {
Name string
Description string
Schema json.RawMessage
}
type Message ¶
type Message struct {
Role Role `json:"role"`
Parts []Part `json:"parts"`
Metadata metadata.Map `json:"metadata,omitzero"`
}
Message is one provider-neutral conversation entry. Parts retain their order so interleaved assistant text, reasoning, and tool calls round-trip. Clone recursively owns every mutable protocol value. Text projection concatenates only text parts and deliberately ignores reasoning, media, and tool payloads.
func NewAssistantMessage ¶
func NewSystemMessage ¶
func NewToolMessage ¶
func NewToolMessage(results ...ToolResult) Message
func NewUserMessage ¶
func (Message) MarshalJSON ¶
func (*Message) UnmarshalJSON ¶
type Model ¶
type Model interface {
// Call performs one complete model exchange. It must reject an invalid
// request before provider I/O, must not retain or mutate request, and
// transfers ownership of the returned response to the caller. Context
// cancellation remains identifiable through errors.Is.
Call(ctx context.Context, request *Request) (*Response, error)
}
Model is the minimal synchronous chat capability. Implementations must validate request before provider I/O, honor context cancellation, and return a provider-neutral Response. Cancellation errors must retain context.Canceled or context.DeadlineExceeded for errors.Is.
Streaming, default configuration, and provider identity are independent concerns and deliberately are not methods of Model.
func Wrap ¶
func Wrap(model Model, middlewares ...CallMiddleware) Model
Wrap composes call middlewares around model. The first middleware is the outermost wrapper. Nil entries are ignored so optional middleware can be supplied without a separate branch.
type Options ¶
type Options struct {
Model string `json:"model,omitempty"`
OutputFormat *OutputFormat `json:"output_format,omitempty"`
FrequencyPenalty *float64 `json:"frequency_penalty,omitempty"`
MaxOutputTokens *int64 `json:"max_output_tokens,omitempty"`
PresencePenalty *float64 `json:"presence_penalty,omitempty"`
ReasoningEffort ReasoningEffort `json:"reasoning_effort,omitempty"`
Stop []string `json:"stop,omitzero"`
Temperature *float64 `json:"temperature,omitempty"`
TopK *int64 `json:"top_k,omitempty"`
TopP *float64 `json:"top_p,omitempty"`
Extensions metadata.Extensions `json:"extensions,omitzero"`
}
Options contains provider-neutral per-request generation overrides. Its zero value means provider defaults. Resolve overlays only explicitly populated fields, merges namespaced extensions, snapshots mutable values, and leaves both source values unchanged.
func (Options) MarshalJSON ¶
func (*Options) UnmarshalJSON ¶
type Output ¶
type Output struct {
Message *Message `json:"message,omitempty"`
FinishReason FinishReason `json:"finish_reason,omitempty"`
Metadata *OutputMetadata `json:"metadata,omitempty"`
}
Output is the complete single provider generation produced by a chat call. Message may be nil when the provider completed without a portable content item, but FinishReason is always present.
func NewOutput ¶
func NewOutput(message *Message, finishReason FinishReason, outputMetadata *OutputMetadata) (*Output, error)
func (Output) MarshalJSON ¶
func (*Output) UnmarshalJSON ¶
type OutputFormat ¶
type OutputFormat struct {
Type OutputFormatType `json:"type"`
Name string `json:"name,omitempty"`
Description string `json:"description,omitempty"`
Schema json.RawMessage `json:"schema,omitempty"`
}
OutputFormat is the provider-neutral representation contract for one model result. Name, Description, and Schema belong only to OutputFormatJSONSchema. Provider adapters decode Schema into their native SDK shape when supported. Schema bytes are always snapshotted at construction and cloning boundaries.
func NewJSONSchemaOutputFormat ¶
func NewJSONSchemaOutputFormat(config JSONSchemaConfig) (OutputFormat, error)
func NewOutputFormat ¶
func NewOutputFormat(formatType OutputFormatType) (OutputFormat, error)
func (*OutputFormat) Clone ¶
func (o *OutputFormat) Clone() *OutputFormat
func (OutputFormat) MarshalJSON ¶
func (o OutputFormat) MarshalJSON() ([]byte, error)
func (*OutputFormat) SchemaAs ¶
func (o *OutputFormat) SchemaAs[T any]() (T, error)
func (*OutputFormat) UnmarshalJSON ¶
func (o *OutputFormat) UnmarshalJSON(data []byte) error
func (OutputFormat) Validate ¶
func (o OutputFormat) Validate() error
type OutputFormatType ¶
type OutputFormatType string
OutputFormatType identifies the representation requested for a chat result. Provider adapters map the format to an equivalent native control or reject it.
const ( OutputFormatText OutputFormatType = "text" OutputFormatJSON OutputFormatType = "json" OutputFormatJSONSchema OutputFormatType = "json_schema" )
type OutputMetadata ¶
OutputMetadata holds provider-specific metadata for one generation output.
func (OutputMetadata) MarshalJSON ¶
func (o OutputMetadata) MarshalJSON() ([]byte, error)
func (*OutputMetadata) UnmarshalJSON ¶
func (o *OutputMetadata) UnmarshalJSON(data []byte) error
type Part ¶
type Part struct {
Kind PartKind `json:"kind"`
Text string `json:"text,omitempty"`
Media *media.Media `json:"media,omitempty"`
ReasoningState []byte `json:"reasoning_state,omitempty"`
ToolCall *ToolCall `json:"tool_call,omitempty"`
ToolResult *ToolResult `json:"tool_result,omitempty"`
Citations []Citation `json:"citations,omitempty"`
Metadata metadata.Map `json:"metadata,omitzero"`
}
Part is a tagged protocol value. Kind selects exactly one payload shape: Text, Media, reasoning Text/ReasoningState, ToolCall, or ToolResult. Citations annotate only text parts. Metadata retains JSON-safe, part-scoped provider state without weakening the common semantic payload.
func NewMediaPart ¶
func NewReasoningPart ¶
func NewRefusalPart ¶ added in v0.13.0
func NewTextPart ¶
func NewToolCallPart ¶
func NewToolResultPart ¶
func NewToolResultPart(result ToolResult) Part
func (Part) MarshalJSON ¶
func (*Part) UnmarshalJSON ¶
type PartDelta ¶ added in v0.13.0
type PartDelta struct {
Kind PartDeltaKind `json:"kind"`
Text string `json:"text,omitempty"`
Media *media.Media `json:"media,omitempty"`
ReasoningState []byte `json:"reasoning_state,omitempty"`
ToolCall *ToolCallDelta `json:"tool_call,omitempty"`
Citation *Citation `json:"citation,omitempty"`
Metadata metadata.Map `json:"metadata,omitzero"`
}
PartDelta is one transport increment. It is intentionally distinct from Part because incomplete tool arguments and citation attachment are not valid stable message content.
func NewCitationDelta ¶ added in v0.13.0
func NewMediaDelta ¶ added in v0.13.0
func NewReasoningDelta ¶ added in v0.13.0
func NewRefusalDelta ¶ added in v0.13.0
func NewTextDelta ¶ added in v0.13.0
func NewToolCallDelta ¶ added in v0.13.0
func NewToolCallDelta(delta ToolCallDelta) PartDelta
func (PartDelta) MarshalJSON ¶ added in v0.13.0
func (*PartDelta) UnmarshalJSON ¶ added in v0.13.0
type PartDeltaKind ¶ added in v0.13.0
type PartDeltaKind string
const ( PartDeltaText PartDeltaKind = "text" PartDeltaMedia PartDeltaKind = "media" PartDeltaReasoning PartDeltaKind = "reasoning" PartDeltaToolCall PartDeltaKind = "tool_call" PartDeltaCitation PartDeltaKind = "citation" PartDeltaRefusal PartDeltaKind = "refusal" )
func (PartDeltaKind) Valid ¶ added in v0.13.0
func (p PartDeltaKind) Valid() bool
type PartKind ¶
type PartKind string
PartKind identifies which payload in Part is active.
const ( // PartText carries plain text. PartText PartKind = "text" // PartMedia carries an image, audio, document, or other media value. PartMedia PartKind = "media" // PartReasoning carries visible reasoning and optional opaque replay state. PartReasoning PartKind = "reasoning" // PartToolCall carries one tool invocation request. PartToolCall PartKind = "tool_call" // PartToolResult carries one tool execution result. PartToolResult PartKind = "tool_result" // PartRefusal carries a model refusal separately from ordinary output text. PartRefusal PartKind = "refusal" )
type ReasoningEffort ¶
type ReasoningEffort string
ReasoningEffort is a provider-neutral reasoning intensity selected from a model's advertised values. It is intentionally open rather than a fixed enum: the selected model owns its accepted vocabulary.
func (ReasoningEffort) Validate ¶
func (r ReasoningEffort) Validate() error
Validate rejects values whose identity would change under trimming. Empty is valid and asks the provider adapter to use the selected model's default.
type Request ¶
type Request struct {
Messages []Message `json:"messages"`
Tools []ToolDefinition `json:"tools,omitempty"`
ToolChoice *ToolChoice `json:"tool_choice,omitempty"`
Options Options `json:"options,omitzero"`
}
Request is the complete provider-neutral input to a chat model. It contains only serializable protocol values; executable tools and invocation state are supplied separately by higher-level runtimes. Construction and cloning snapshot every mutable nested protocol value before middleware or providers receive it.
func NewRequest ¶
func (Request) MarshalJSON ¶
func (*Request) UnmarshalJSON ¶
type Response ¶
type Response struct {
Output *Output `json:"output,omitempty"`
Metadata *ResponseMetadata `json:"metadata,omitempty"`
}
Response is one complete provider output with exactly one generation output.
func NewResponse ¶
func NewResponse(output *Output, responseMetadata *ResponseMetadata) (*Response, error)
func (Response) MarshalJSON ¶
func (*Response) UnmarshalJSON ¶
type ResponseAccumulator ¶
type ResponseAccumulator struct {
// contains filtered or unexported fields
}
ResponseAccumulator is the only promotion path from transport deltas to a complete Response. Its zero value is ready to use and Add is atomic.
func (*ResponseAccumulator) Add ¶
func (r *ResponseAccumulator) Add(delta *ResponseDelta) error
func (*ResponseAccumulator) Response ¶
func (r *ResponseAccumulator) Response() (*Response, error)
Response promotes the accumulated stream only after a terminal finish reason has been observed.
func (*ResponseAccumulator) Text ¶ added in v0.13.0
func (r *ResponseAccumulator) Text() string
Text returns the currently accumulated visible text without manufacturing a partial Response.
type ResponseDelta ¶ added in v0.13.0
type ResponseDelta struct {
Parts []PartDelta `json:"parts,omitempty"`
MessageMetadata metadata.Map `json:"message_metadata,omitzero"`
FinishReason FinishReason `json:"finish_reason,omitempty"`
OutputMetadata *OutputMetadata `json:"output_metadata,omitempty"`
Metadata *ResponseMetadata `json:"metadata,omitempty"`
}
ResponseDelta is one independently owned stream increment. Usage is a cumulative snapshot; an optional finish reason marks the terminal increment.
func (*ResponseDelta) Clone ¶ added in v0.13.0
func (r *ResponseDelta) Clone() *ResponseDelta
func (ResponseDelta) MarshalJSON ¶ added in v0.13.0
func (r ResponseDelta) MarshalJSON() ([]byte, error)
func (*ResponseDelta) Text ¶ added in v0.13.0
func (r *ResponseDelta) Text() string
func (*ResponseDelta) UnmarshalJSON ¶ added in v0.13.0
func (r *ResponseDelta) UnmarshalJSON(data []byte) error
func (*ResponseDelta) Validate ¶ added in v0.13.0
func (r *ResponseDelta) Validate() error
type ResponseMetadata ¶
type ResponseMetadata struct {
ID string `json:"id,omitempty"`
Model string `json:"model,omitempty"`
Usage Usage `json:"usage,omitzero"`
CreatedAt time.Time `json:"created_at,omitzero"`
Extra metadata.Map `json:"extra,omitzero"`
}
ResponseMetadata holds provider identity, usage, and response-scoped extras.
func (ResponseMetadata) MarshalJSON ¶
func (r ResponseMetadata) MarshalJSON() ([]byte, error)
func (*ResponseMetadata) UnmarshalJSON ¶
func (r *ResponseMetadata) UnmarshalJSON(data []byte) error
type StreamMiddleware ¶
StreamMiddleware wraps the optional Streamer capability.
type Streamer ¶
type Streamer interface {
// Stream starts provider work lazily when the sequence is iterated. Each
// yielded response is an independently owned delta accepted by
// ResponseAccumulator. Stopping iteration releases provider resources before
// the iterator returns; a terminal error is yielded at most once.
Stream(ctx context.Context, request *Request) iter.Seq2[*ResponseDelta, error]
}
Streamer is the optional streaming chat capability. It is independent of Model so an implementation is not forced to provide a synthetic synchronous Call path, and a call-only implementation is not forced to fake streaming.
Every successful yield is a valid ResponseDelta. Usage, when present, is a cumulative snapshot rather than a per-chunk increment. On failure the sequence yields (nil, err) once and terminates. Context errors retain their errors.Is identity. When the caller stops iteration, implementations must synchronously release provider resources without yielding a cancellation error or leaving a detached goroutine behind. ResponseAccumulator defines the provider-neutral aggregation semantics.
func WrapStream ¶
func WrapStream(streamer Streamer, middlewares ...StreamMiddleware) Streamer
WrapStream composes stream middlewares around streamer using the same outermost-first order as Wrap.
type StreamerFunc ¶
func (StreamerFunc) Stream ¶
func (s StreamerFunc) Stream(ctx context.Context, request *Request) iter.Seq2[*ResponseDelta, error]
type ToolCall ¶
type ToolCall struct {
ID string `json:"id"`
Name string `json:"name"`
Arguments string `json:"arguments,omitempty"`
}
ToolCall is one complete, untrusted model proposal to invoke a named tool. Arguments retains the provider's JSON text so malformed final model output remains serializable. A runtime must promote the proposal through the bound Tool schema before exposing it to capabilities or execution.
type ToolCallDelta ¶
type ToolCallDelta struct {
ID string `json:"id"`
Name string `json:"name"`
Arguments string `json:"arguments,omitempty"`
}
ToolCallDelta is one streaming fragment of a ToolCall. It cannot appear in a Request; ResponseAccumulator is the only boundary that promotes fragments to a complete ToolCall.
func (ToolCallDelta) Validate ¶
func (t ToolCallDelta) Validate() error
type ToolChoice ¶ added in v0.13.0
type ToolChoice struct {
Mode ToolChoiceMode `json:"mode"`
Name string `json:"name,omitempty"`
Parallelism ToolParallelism `json:"parallelism,omitempty"`
}
ToolChoice owns how a model may select client tools. The zero parallelism delegates concurrency policy to the provider.
func (*ToolChoice) Clone ¶ added in v0.13.0
func (t *ToolChoice) Clone() *ToolChoice
func (ToolChoice) Validate ¶ added in v0.13.0
func (t ToolChoice) Validate() error
type ToolChoiceMode ¶ added in v0.13.0
type ToolChoiceMode string
const ( ToolChoiceAuto ToolChoiceMode = "auto" ToolChoiceNone ToolChoiceMode = "none" ToolChoiceRequired ToolChoiceMode = "required" ToolChoiceNamed ToolChoiceMode = "named" )
func (ToolChoiceMode) Valid ¶ added in v0.13.0
func (t ToolChoiceMode) Valid() bool
type ToolDefinition ¶
type ToolDefinition struct {
Name string `json:"name"`
Description string `json:"description,omitempty"`
InputSchema json.RawMessage `json:"input_schema"`
}
ToolDefinition is the serializable description exposed to a model. Tool execution belongs to package tool and is deliberately absent here.
func (ToolDefinition) Clone ¶
func (t ToolDefinition) Clone() ToolDefinition
func (ToolDefinition) MarshalJSON ¶
func (t ToolDefinition) MarshalJSON() ([]byte, error)
func (*ToolDefinition) UnmarshalJSON ¶
func (t *ToolDefinition) UnmarshalJSON(data []byte) error
func (ToolDefinition) Validate ¶
func (t ToolDefinition) Validate() error
type ToolOutput ¶
type ToolOutput struct {
Content []Part `json:"content,omitempty"`
Details json.RawMessage `json:"details,omitempty"`
}
ToolOutput is the provider-neutral value produced by a Tool. Content is the model-visible ordered text/media representation. Details is optional JSON for structured consumers; providers use its encoded JSON as the model-visible fallback only when Content is empty.
Content deliberately reuses Part so media has one representation across the chat protocol. Only text and media parts are valid here; reasoning, calls, refusals, and results are rejected.
func NewJSONToolOutput ¶
func NewJSONToolOutput(value json.RawMessage) (ToolOutput, error)
NewJSONToolOutput returns a structured output whose exact JSON encoding is preserved. The value must be one complete RFC 7493 JSON document.
func NewTextToolOutput ¶
func NewTextToolOutput(text string) ToolOutput
NewTextToolOutput returns a text output. Empty text is represented by the valid zero ToolOutput rather than an invalid empty text Part.
func (ToolOutput) Clone ¶
func (t ToolOutput) Clone() ToolOutput
func (ToolOutput) MarshalJSON ¶ added in v0.13.0
func (t ToolOutput) MarshalJSON() ([]byte, error)
func (ToolOutput) Text ¶
func (t ToolOutput) Text() (string, bool)
Text returns the lossless text projection used by providers whose tool result protocol accepts only strings. It reports false when Content contains media so adapters cannot silently discard it. Details is encoded only when Content is empty.
func (*ToolOutput) UnmarshalJSON ¶ added in v0.13.0
func (t *ToolOutput) UnmarshalJSON(data []byte) error
func (ToolOutput) Validate ¶
func (t ToolOutput) Validate() error
type ToolParallelism ¶ added in v0.13.0
type ToolParallelism string
const ( ToolParallelismAllow ToolParallelism = "allow" ToolParallelismSingle ToolParallelism = "single" )
func (ToolParallelism) Valid ¶ added in v0.13.0
func (t ToolParallelism) Valid() bool
type ToolResult ¶
type ToolResult struct {
ID string `json:"id"`
Name string `json:"name"`
Output ToolOutput `json:"output"`
IsError bool `json:"is_error,omitempty"`
}
ToolResult is one tool execution result correlated to a ToolCall by ID.
func (ToolResult) Clone ¶
func (t ToolResult) Clone() ToolResult
func (ToolResult) Validate ¶
func (t ToolResult) Validate() error
type Usage ¶
type Usage struct {
// InputTokens is the total processed input count. Provider cache-read and
// cache-write counts, when reported, are breakdowns included in this total.
InputTokens int64 `json:"input_tokens,omitempty"`
OutputTokens int64 `json:"output_tokens,omitempty"`
ReasoningTokens *int64 `json:"reasoning_tokens,omitempty"`
CacheReadInputTokens *int64 `json:"cache_read_input_tokens,omitempty"`
CacheWriteInputTokens *int64 `json:"cache_write_input_tokens,omitempty"`
}
Usage records provider-neutral token counts. Breakdown pointers distinguish an explicitly reported zero from an unsupported dimension.