opencode/packages/core/src/session/event.ts

import { Schema } from "effect"
import { ProviderMetadata, ToolContent } from "@opencode-ai/llm"
import { EventV2 } from "../event"
import { ModelV2 } from "../model"
import { NonNegativeInt } from "../schema"
import { V2Schema } from "../v2-schema"
import { FileAttachment, Prompt } from "./prompt"
import { SessionSchema } from "./schema"
import { Location } from "../location"
import { RelativePath } from "../schema"
import { SessionMessageID } from "./message-id"

export { FileAttachment }

export const Source = Schema.Struct({
  start: NonNegativeInt,
  end: NonNegativeInt,
  text: Schema.String,
}).annotate({
  identifier: "session.next.event.source",
})
export type Source = typeof Source.Type

const Base = {
  timestamp: V2Schema.DateTimeUtcFromMillis,
  sessionID: SessionSchema.ID,
}

const options = {
  durable: {
    aggregate: "sessionID",
    version: 1,
  },
} as const
const stepSettlementOptions = {
  durable: {
    aggregate: "sessionID",
    version: 2,
  },
} as const

export const UnknownError = Schema.Struct({
  type: Schema.Literal("unknown"),
  message: Schema.String,
}).annotate({
  identifier: "Session.Error.Unknown",
})
export type UnknownError = typeof UnknownError.Type

export const AgentSwitched = EventV2.define({
  type: "session.next.agent.switched",
  ...options,
  schema: {
    ...Base,
    messageID: SessionMessageID.ID,
    agent: Schema.String,
  },
})
export type AgentSwitched = typeof AgentSwitched.Type

export const ModelSwitched = EventV2.define({
  type: "session.next.model.switched",
  ...options,
  schema: {
    ...Base,
    messageID: SessionMessageID.ID,
    model: ModelV2.Ref,
  },
})
export type ModelSwitched = typeof ModelSwitched.Type

export const Moved = EventV2.define({
  type: "session.next.moved",
  ...options,
  schema: {
    ...Base,
    location: Location.Ref,
    subdirectory: RelativePath.pipe(Schema.optional),
  },
})
export type Moved = typeof Moved.Type

export const Prompted = EventV2.define({
  type: "session.next.prompted",
  ...options,
  schema: {
    ...Base,
    messageID: SessionMessageID.ID,
    prompt: Prompt,
    delivery: Schema.Literals(["steer", "queue"]),
  },
})
export type Prompted = typeof Prompted.Type

export namespace PromptLifecycle {
  export const Admitted = EventV2.define({
    type: "session.next.prompt.admitted",
    ...options,
    schema: {
      ...Base,
      messageID: SessionMessageID.ID,
      prompt: Prompt,
      delivery: Schema.Literals(["steer", "queue"]),
    },
  })
  export type Admitted = typeof Admitted.Type

  export const Promoted = EventV2.define({
    type: "session.next.prompt.promoted",
    ...options,
    schema: {
      ...Base,
      messageID: SessionMessageID.ID,
      prompt: Prompt,
      timeCreated: V2Schema.DateTimeUtcFromMillis,
    },
  })
  export type Promoted = typeof Promoted.Type
}

export const InterruptRequested = EventV2.define({
  type: "session.next.interrupt.requested",
  ...options,
  schema: Base,
})
export type InterruptRequested = typeof InterruptRequested.Type

export const ContextUpdated = EventV2.define({
  type: "session.next.context.updated",
  ...options,
  schema: {
    ...Base,
    messageID: SessionMessageID.ID,
    text: Schema.String,
  },
})
export type ContextUpdated = typeof ContextUpdated.Type

export const Synthetic = EventV2.define({
  type: "session.next.synthetic",
  ...options,
  schema: {
    ...Base,
    messageID: SessionMessageID.ID,
    text: Schema.String,
  },
})
export type Synthetic = typeof Synthetic.Type

export namespace Shell {
  export const Started = EventV2.define({
    type: "session.next.shell.started",
    ...options,
    schema: {
      ...Base,
      messageID: SessionMessageID.ID,
      callID: Schema.String,
      command: Schema.String,
    },
  })
  export type Started = typeof Started.Type

  export const Ended = EventV2.define({
    type: "session.next.shell.ended",
    ...options,
    schema: {
      ...Base,
      callID: Schema.String,
      output: Schema.String,
    },
  })
  export type Ended = typeof Ended.Type
}

export namespace Step {
  export const Started = EventV2.define({
    type: "session.next.step.started",
    ...options,
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      agent: Schema.String,
      model: ModelV2.Ref,
      snapshot: Schema.String.pipe(Schema.optional),
    },
  })
  export type Started = typeof Started.Type

  export const Ended = EventV2.define({
    type: "session.next.step.ended",
    ...stepSettlementOptions,
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      finish: Schema.String,
      cost: Schema.Finite,
      tokens: Schema.Struct({
        input: Schema.Finite,
        output: Schema.Finite,
        reasoning: Schema.Finite,
        cache: Schema.Struct({
          read: Schema.Finite,
          write: Schema.Finite,
        }),
      }),
      snapshot: Schema.String.pipe(Schema.optional),
    },
  })
  export type Ended = typeof Ended.Type

  export const Failed = EventV2.define({
    type: "session.next.step.failed",
    ...stepSettlementOptions,
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      error: UnknownError,
    },
  })
  export type Failed = typeof Failed.Type
}

export namespace Text {
  export const Started = EventV2.define({
    type: "session.next.text.started",
    ...options,
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      textID: Schema.String,
    },
  })
  export type Started = typeof Started.Type

  // Stream fragments are live-only; Text.Ended is the replayable full-value boundary.
  export const Delta = EventV2.define({
    type: "session.next.text.delta",
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      textID: Schema.String,
      delta: Schema.String,
    },
  })
  export type Delta = typeof Delta.Type

  export const Ended = EventV2.define({
    type: "session.next.text.ended",
    ...options,
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      textID: Schema.String,
      text: Schema.String,
    },
  })
  export type Ended = typeof Ended.Type
}

export namespace Reasoning {
  export const Started = EventV2.define({
    type: "session.next.reasoning.started",
    ...options,
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      reasoningID: Schema.String,
      providerMetadata: ProviderMetadata.pipe(Schema.optional),
    },
  })
  export type Started = typeof Started.Type

  // Stream fragments are live-only; Reasoning.Ended is the replayable full-value boundary.
  export const Delta = EventV2.define({
    type: "session.next.reasoning.delta",
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      reasoningID: Schema.String,
      delta: Schema.String,
    },
  })
  export type Delta = typeof Delta.Type

  export const Ended = EventV2.define({
    type: "session.next.reasoning.ended",
    ...options,
    schema: {
      ...Base,
      assistantMessageID: SessionMessageID.ID,
      reasoningID: Schema.String,
      text: Schema.String,
      providerMetadata: ProviderMetadata.pipe(Schema.optional),
    },
  })
  export type Ended = typeof Ended.Type
}

export namespace Tool {
  const ToolBase = {
    ...Base,
    assistantMessageID: SessionMessageID.ID,
    callID: Schema.String,
  }

  export namespace Input {
    export const Started = EventV2.define({
      type: "session.next.tool.input.started",
      ...options,
      schema: {
        ...ToolBase,
        name: Schema.String,
      },
    })
    export type Started = typeof Started.Type

    // Stream fragments are live-only; Input.Ended is the replayable raw-input boundary.
    export const Delta = EventV2.define({
      type: "session.next.tool.input.delta",
      schema: {
        ...ToolBase,
        delta: Schema.String,
      },
    })
    export type Delta = typeof Delta.Type

    export const Ended = EventV2.define({
      type: "session.next.tool.input.ended",
      ...options,
      schema: {
        ...ToolBase,
        text: Schema.String,
      },
    })
    export type Ended = typeof Ended.Type
  }

  export const Called = EventV2.define({
    type: "session.next.tool.called",
    ...options,
    schema: {
      ...ToolBase,
      tool: Schema.String,
      input: Schema.Record(Schema.String, Schema.Unknown),
      provider: Schema.Struct({
        executed: Schema.Boolean,
        metadata: ProviderMetadata.pipe(Schema.optional),
      }),
    },
  })
  export type Called = typeof Called.Type

  /**
   * Replayable bounded running-tool state. Tools should checkpoint semantic
   * transitions or at a bounded cadence, not persist every stdout/stderr chunk.
   */
  export const Progress = EventV2.define({
    type: "session.next.tool.progress",
    ...options,
    schema: {
      ...ToolBase,
      structured: Schema.Record(Schema.String, Schema.Any),
      content: Schema.Array(ToolContent),
    },
  })
  export type Progress = typeof Progress.Type

  export const Success = EventV2.define({
    type: "session.next.tool.success",
    ...options,
    schema: {
      ...ToolBase,
      structured: Schema.Record(Schema.String, Schema.Any),
      content: Schema.Array(ToolContent),
      outputPaths: Schema.Array(Schema.String).pipe(Schema.optional),
      result: Schema.Unknown.pipe(Schema.optional),
      provider: Schema.Struct({
        executed: Schema.Boolean,
        metadata: ProviderMetadata.pipe(Schema.optional),
      }),
    },
  })
  export type Success = typeof Success.Type

  export const Failed = EventV2.define({
    type: "session.next.tool.failed",
    ...options,
    schema: {
      ...ToolBase,
      error: UnknownError,
      result: Schema.Unknown.pipe(Schema.optional),
      provider: Schema.Struct({
        executed: Schema.Boolean,
        metadata: ProviderMetadata.pipe(Schema.optional),
      }),
    },
  })
  export type Failed = typeof Failed.Type
}

export const RetryError = Schema.Struct({
  message: Schema.String,
  statusCode: Schema.Finite.pipe(Schema.optional),
  isRetryable: Schema.Boolean,
  responseHeaders: Schema.Record(Schema.String, Schema.String).pipe(Schema.optional),
  responseBody: Schema.String.pipe(Schema.optional),
  metadata: Schema.Record(Schema.String, Schema.String).pipe(Schema.optional),
}).annotate({
  identifier: "session.next.retry_error",
})
export type RetryError = typeof RetryError.Type

export const Retried = EventV2.define({
  type: "session.next.retried",
  ...options,
  schema: {
    ...Base,
    attempt: Schema.Finite,
    error: RetryError,
  },
})
export type Retried = typeof Retried.Type

export namespace Compaction {
  export const Started = EventV2.define({
    type: "session.next.compaction.started",
    ...options,
    schema: {
      ...Base,
      messageID: SessionMessageID.ID,
      reason: Schema.Union([Schema.Literal("auto"), Schema.Literal("manual")]),
    },
  })
  export type Started = typeof Started.Type

  export const Delta = EventV2.define({
    type: "session.next.compaction.delta",
    schema: {
      ...Base,
      messageID: SessionMessageID.ID,
      text: Schema.String,
    },
  })
  export type Delta = typeof Delta.Type

  // Retain the unpublished v1 decoder so stored beta events remain replayable.
  export const EndedV1 = EventV2.define({
    type: "session.next.compaction.ended",
    ...options,
    schema: {
      ...Base,
      text: Schema.String,
      include: Schema.String.pipe(Schema.optional),
    },
  })

  export const Ended = EventV2.define({
    type: "session.next.compaction.ended",
    durable: { aggregate: "sessionID", version: 2 },
    schema: {
      ...Base,
      messageID: SessionMessageID.ID,
      reason: Started.data.fields.reason,
      text: Schema.String,
      recent: Schema.String,
    },
  })
  export type Ended = typeof Ended.Type
}

const DurableDefinitions = [
  AgentSwitched,
  ModelSwitched,
  Moved,
  Prompted,
  PromptLifecycle.Admitted,
  PromptLifecycle.Promoted,
  InterruptRequested,
  ContextUpdated,
  Synthetic,
  Shell.Started,
  Shell.Ended,
  Step.Started,
  Step.Ended,
  Step.Failed,
  Text.Started,
  Text.Ended,
  Tool.Input.Started,
  Tool.Input.Ended,
  Tool.Called,
  Tool.Progress,
  Tool.Success,
  Tool.Failed,
  Reasoning.Started,
  Reasoning.Ended,
  Retried,
  Compaction.Started,
  Compaction.Ended,
] as const
const EphemeralDefinitions = [Text.Delta, Tool.Input.Delta, Reasoning.Delta, Compaction.Delta] as const

export const Durable = Schema.Union(DurableDefinitions, { mode: "oneOf" }).pipe(Schema.toTaggedUnion("type"))
export type DurableEvent = typeof Durable.Type

export const All = Schema.Union([...DurableDefinitions, ...EphemeralDefinitions], { mode: "oneOf" }).pipe(
  Schema.toTaggedUnion("type"),
)
export type Event = typeof All.Type
export type Type = Event["type"]

export * as SessionEvent from "./event"