a2a

type Artifact struct {
	ArtifactID  string         `json:"artifactId"`
	Name        string         `json:"name,omitempty"`
	Description string         `json:"description,omitempty"`
	Parts       []Part         `json:"parts"`
	Metadata    map[string]any `json:"metadata,omitempty"`
	Extensions  []string       `json:"extensions,omitempty"`
}

type AuthenticationInfo struct {
	Scheme      string `json:"scheme"`
	Credentials string `json:"credentials,omitempty"`
}

type CancelTaskRequest struct {
	Tenant   string         `json:"tenant,omitempty"`
	ID       string         `json:"id"`
	Metadata map[string]any `json:"metadata,omitempty"`
}

type Capabilities struct {
	Streaming         bool `json:"streaming"`
	PushNotifications bool `json:"pushNotifications"`
	ExtendedAgentCard bool `json:"extendedAgentCard,omitempty"`
}

type Config struct {
	// Skills is what the agent can do; at least one, unique ids, and
	// every Handler non-nil.
	Skills []Skill
	// Store persists tasks and push configs. Nil → NewMemoryStore().
	Store Store
	// Router picks the skill for a message. Nil → DefaultRouter.
	Router Router
	// Owner resolves the caller for every request. ok=false → HTTP 401
	// and CodeUnauthenticated. Nil is a NewServer error.
	Owner func(r *http.Request) (owner string, ok bool)
	// ExtendedCard, when set, serves GetExtendedAgentCard. Nil → the
	// method answers CodeExtendedAgentCardNotConfigured and
	// Capabilities().ExtendedAgentCard is false.
	ExtendedCard func(ctx context.Context, owner string) (map[string]any, error)
	// Push tunes push-notification delivery; see PushOptions.
	Push PushOptions
	// Logger for handler failures, drops, and push errors. Nil →
	// slog.Default().
	Logger *slog.Logger
	// AllowedOrigins permits browser Origins that are not same-origin
	// with the request: tunnels (ngrok, Codespaces) and split-origin
	// web clients. The default posture refuses a present Origin naming
	// any authority other than the request's own Host, mirroring the
	// MCP transport's cross-origin gate; native A2A clients send no
	// Origin and always pass.
	AllowedOrigins []string
	// MaxBodyBytes caps one request body. Default 1 MiB.
	MaxBodyBytes int64
	// TaskTimeout is the ceiling on one skill-handler run. Default
	// 5 minutes.
	TaskTimeout time.Duration
	// MaxHistory caps stored history per task (oldest dropped).
	// Default 200 messages.
	MaxHistory int
	// DefaultPageSize and MaxPageSize bound ListTasks paging.
	// Defaults 50 / 200.
	DefaultPageSize, MaxPageSize int

	// TerminalTaskRetention bounds how many TERMINAL task rows
	// (completed / failed / canceled / rejected) one owner retains:
	// past the bound the OLDEST terminal rows are deleted after each
	// settle. 0 = 64 (every row carries the caller's message body, and
	// the default store is in-RAM, so cheap authenticated writes must
	// not grow it without end); negative disables trimming for hosts
	// that own retention themselves. Applies to stores implementing
	// RetentionTrimmer — both built-ins do.
	TerminalTaskRetention int

	// MaxPushConfigsPerTask bounds push-notification configs per task
	// (each one fans a delivery goroutine out per event): past the
	// bound the OLDEST configs are deleted. 0 = 8; negative disables.
	MaxPushConfigsPerTask int

	// MaxStreamSeatsPerOwner bounds the concurrent SSE streams
	// (SubscribeToTask + SendStreamingMessage) ONE owner may hold: each
	// pins a relay goroutine, a bus channel, and tickers for the
	// stream's whole life. 0 = 16 (the default every stream surface in
	// the tree shares); negative lifts the cap for deployments that
	// bound streams elsewhere.
	MaxStreamSeatsPerOwner int

	// MaxConcurrentRunsPerOwner bounds the concurrent skill-handler runs
	// one owner may start, including ReturnImmediately runs. 0 = 16;
	// negative disables the cap for deployments that bound runs elsewhere.
	MaxConcurrentRunsPerOwner int

	// StreamSeatOverflow selects what an owner at MaxStreamSeatsPerOwner
	// does with their next stream: stream.SeatOverflowRefuse (the
	// default) answers 429 at connect; stream.SeatOverflowEvictOldest
	// closes that owner's oldest stream and seats the new one — the
	// multi-tab-friendly policy for clients that reconnect faster than
	// a half-open connection's seat is reclaimed.
	StreamSeatOverflow stream.SeatOverflowPolicy
}

type DeleteTaskPushNotificationConfigRequest struct {
	Tenant string `json:"tenant,omitempty"`
	TaskID string `json:"taskId"`
	ID     string `json:"id"`
}

type Error struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
	Data    any    `json:"data,omitempty"`
}

type GetExtendedAgentCardRequest struct {
	Tenant string `json:"tenant,omitempty"`
}

type GetTaskPushNotificationConfigRequest struct {
	Tenant string `json:"tenant,omitempty"`
	TaskID string `json:"taskId"`
	ID     string `json:"id"`
}

type GetTaskRequest struct {
	Tenant        string `json:"tenant,omitempty"`
	ID            string `json:"id"`
	HistoryLength *int   `json:"historyLength,omitempty"`
}

type Handler func(ctx context.Context, t TaskContext) error

type ListQuery struct {
	ContextID string
	Status    TaskState
	// After filters to tasks whose status timestamp is after this instant
	// (zero: no filter).
	After  time.Time
	Limit  int
	Offset int
}

type ListTaskPushNotificationConfigsRequest struct {
	Tenant    string `json:"tenant,omitempty"`
	TaskID    string `json:"taskId"`
	PageSize  *int   `json:"pageSize,omitempty"`
	PageToken string `json:"pageToken,omitempty"`
}

type ListTaskPushNotificationConfigsResponse struct {
	Configs       []PushNotificationConfig `json:"configs"`
	NextPageToken string                   `json:"nextPageToken,omitempty"`
}

type ListTasksRequest struct {
	Tenant               string     `json:"tenant,omitempty"`
	ContextID            string     `json:"contextId,omitempty"`
	Status               TaskState  `json:"status,omitempty"`
	PageSize             *int       `json:"pageSize,omitempty"`
	PageToken            string     `json:"pageToken,omitempty"`
	HistoryLength        *int       `json:"historyLength,omitempty"`
	StatusTimestampAfter *Timestamp `json:"statusTimestampAfter,omitempty"`
	IncludeArtifacts     *bool      `json:"includeArtifacts,omitempty"`
}

type ListTasksResponse struct {
	Tasks         []Task `json:"tasks"`
	NextPageToken string `json:"nextPageToken"`
	PageSize      int    `json:"pageSize"`
	TotalSize     int    `json:"totalSize"`
}

type MemoryStore struct {
	// contains filtered or unexported fields
}

type Message struct {
	MessageID        string         `json:"messageId"`
	ContextID        string         `json:"contextId,omitempty"`
	TaskID           string         `json:"taskId,omitempty"`
	Role             Role           `json:"role"`
	Parts            []Part         `json:"parts"`
	Metadata         map[string]any `json:"metadata,omitempty"`
	Extensions       []string       `json:"extensions,omitempty"`
	ReferenceTaskIDs []string       `json:"referenceTaskIds,omitempty"`
}

type Part struct {
	Text      *string        `json:"text,omitempty"`
	Raw       []byte         `json:"raw,omitempty"`
	URL       *string        `json:"url,omitempty"`
	Data      *any           `json:"data,omitempty"`
	Filename  string         `json:"filename,omitempty"`
	MediaType string         `json:"mediaType,omitempty"`
	Metadata  map[string]any `json:"metadata,omitempty"`
}

type PushConfigRecord struct {
	Config    PushNotificationConfig
	Owner     string
	CreatedAt time.Time
}

type PushNotificationConfig struct {
	Tenant         string              `json:"tenant,omitempty"`
	ID             string              `json:"id,omitempty"`
	TaskID         string              `json:"taskId"`
	URL            string              `json:"url"`
	Token          string              `json:"token,omitempty"`
	Authentication *AuthenticationInfo `json:"authentication,omitempty"`
}

type PushOptions struct {
	// Client delivers notifications. Nil means a 10s-timeout client on
	// the SSRF-guarded transport. A supplied client is used as a
	// template: redirect following is forced off (a 3xx must never carry
	// the notification token to a second host) and, unless AllowPrivate
	// is set, it is wrapped with the dial-time guard, so a caller cannot
	// accidentally opt registered URLs out of the SSRF posture by
	// bringing their own client.
	Client *http.Client
	// AllowPrivate permits internal hosts (loopback, RFC1918, CGNAT,
	// link-local). Tests and internal deployments only: a
	// caller-registered URL that the server POSTs to is an SSRF vector
	// otherwise.
	AllowPrivate bool
	// Disable turns the capability off: Capabilities().PushNotifications
	// reports false, CreateTaskPushNotificationConfig answers
	// CodePushNotificationNotSupported, and a config inside
	// SendMessage's configuration is refused the same way.
	Disable bool
}

type RetentionTrimmer interface {
	// TrimTerminalTasks deletes the owner's OLDEST terminal task rows
	// until at most keep remain. Non-terminal rows are never touched.
	// keep < 0 means unlimited (no-op).
	TrimTerminalTasks(ctx context.Context, owner string, keep int) error
	// TrimPushConfigs deletes the OLDEST push-notification configs
	// registered for (owner, taskID) until at most keep remain.
	// keep < 0 means unlimited (no-op).
	TrimPushConfigs(ctx context.Context, owner, taskID string, keep int) error
}

type Role string

type Router func(ctx context.Context, msg *Message, skills []Skill) (skillID string, err error)

type SQLStore struct {
	// contains filtered or unexported fields
}

type SQLStoreOption func(*SQLStore)

type SendMessageConfiguration struct {
	AcceptedOutputModes        []string                `json:"acceptedOutputModes,omitempty"`
	TaskPushNotificationConfig *PushNotificationConfig `json:"taskPushNotificationConfig,omitempty"`
	HistoryLength              *int                    `json:"historyLength,omitempty"`
	ReturnImmediately          bool                    `json:"returnImmediately,omitempty"`
}

type SendMessageRequest struct {
	Tenant        string                    `json:"tenant,omitempty"`
	Message       *Message                  `json:"message"`
	Configuration *SendMessageConfiguration `json:"configuration,omitempty"`
	Metadata      map[string]any            `json:"metadata,omitempty"`
}

type SendMessageResponse struct {
	Task    *Task    `json:"task,omitempty"`
	Message *Message `json:"message,omitempty"`
}

type Server struct {
	// contains filtered or unexported fields
}

type Skill struct {
	ID          string   `json:"id"`
	Name        string   `json:"name"`
	Description string   `json:"description"`
	Tags        []string `json:"tags"`
	Examples    []string `json:"examples,omitempty"`
	InputModes  []string `json:"inputModes,omitempty"`
	OutputModes []string `json:"outputModes,omitempty"`

	// Handler runs the skill for one message. Nil is a build error.
	Handler Handler `json:"-"`
}

type Store interface {
	CreateTask(ctx context.Context, rec *TaskRecord) error
	// GetTask returns ErrNotFound for an unknown id OR another owner's task.
	GetTask(ctx context.Context, owner, id string) (*TaskRecord, error)
	// UpdateTask persists rec if rec.Version matches the stored row, then
	// increments rec.Version; otherwise ErrConflict.
	UpdateTask(ctx context.Context, rec *TaskRecord) error
	// ListTasks returns the owner's tasks matching q, newest status first,
	// plus the total match count before Limit/Offset.
	ListTasks(ctx context.Context, owner string, q ListQuery) (recs []*TaskRecord, total int, err error)

	CreatePushConfig(ctx context.Context, rec *PushConfigRecord) error
	GetPushConfig(ctx context.Context, owner, taskID, id string) (*PushConfigRecord, error)
	ListPushConfigs(ctx context.Context, owner, taskID string) ([]*PushConfigRecord, error)
	DeletePushConfig(ctx context.Context, owner, taskID, id string) error
}

type StreamResponse struct {
	Task           *Task                    `json:"task,omitempty"`
	Message        *Message                 `json:"message,omitempty"`
	StatusUpdate   *TaskStatusUpdateEvent   `json:"statusUpdate,omitempty"`
	ArtifactUpdate *TaskArtifactUpdateEvent `json:"artifactUpdate,omitempty"`
}

type SubscribeToTaskRequest struct {
	Tenant string `json:"tenant,omitempty"`
	ID     string `json:"id"`
}

type Task struct {
	ID        string         `json:"id"`
	ContextID string         `json:"contextId"`
	Status    TaskStatus     `json:"status"`
	Artifacts []Artifact     `json:"artifacts,omitempty"`
	History   []Message      `json:"history,omitempty"`
	Metadata  map[string]any `json:"metadata,omitempty"`
}

type TaskArtifactUpdateEvent struct {
	TaskID    string         `json:"taskId"`
	ContextID string         `json:"contextId"`
	Artifact  Artifact       `json:"artifact"`
	Append    bool           `json:"append,omitempty"`
	LastChunk bool           `json:"lastChunk,omitempty"`
	Metadata  map[string]any `json:"metadata,omitempty"`
}

type TaskContext interface {
	// Task returns a snapshot of the task as currently persisted.
	Task() *Task
	// Message returns the message this run was started or resumed with.
	Message() *Message
	// Owner returns the principal that owns the task (Config.Owner's
	// value for the request that created it).
	Owner() string
	// Request returns the HTTP request that started or resumed this run,
	// for handlers that re-dispatch into the app with the caller's
	// credentials. Its Context is not the handler's context.
	Request() *http.Request

	// Working moves the task to TASK_STATE_WORKING with an optional agent
	// status message (nil parts: no message). Idempotent once working.
	Working(parts ...Part) error
	// Artifact records an artifact and emits an artifact-update event. An
	// artifact whose ArtifactID matches an existing one replaces it unless
	// append is set, in which case its parts are appended.
	Artifact(a Artifact, append bool) error
	// Complete ends the task in TASK_STATE_COMPLETED with an optional
	// final agent message.
	Complete(parts ...Part) error
	// Fail ends the task in TASK_STATE_FAILED.
	Fail(parts ...Part) error
	// Reject ends the task in TASK_STATE_REJECTED: the agent will not do
	// this work (unknown skill, bad input).
	Reject(parts ...Part) error
	// RequireInput pauses the task in TASK_STATE_INPUT_REQUIRED. The next
	// SendMessage addressed to the task resumes it: the handler runs again
	// with the new message and the task's history.
	RequireInput(parts ...Part) error
	// RequireAuth pauses the task in TASK_STATE_AUTH_REQUIRED, the same
	// way as RequireInput.
	RequireAuth(parts ...Part) error
}

type TaskRecord struct {
	Task    Task
	Owner   string
	SkillID string
	// Version is bumped on every UpdateTask; an update whose Version does
	// not match the stored row fails with ErrConflict.
	Version   int64
	CreatedAt time.Time
	UpdatedAt time.Time
}

type TaskState string

type TaskStatus struct {
	State     TaskState  `json:"state"`
	Message   *Message   `json:"message,omitempty"`
	Timestamp *Timestamp `json:"timestamp,omitempty"`
}

type TaskStatusUpdateEvent struct {
	TaskID    string         `json:"taskId"`
	ContextID string         `json:"contextId"`
	Status    TaskStatus     `json:"status"`
	Metadata  map[string]any `json:"metadata,omitempty"`
}

type Timestamp struct{ time.Time }