Filehigh importancesource

structuredIO.ts

cli/structuredIO.ts

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28720
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2
Exports
27
Imports
10
Keywords

What this is

This page documents one file from the repository and includes its full source so you can read it without leaving the docs site.

Beginner explanation

This file is one piece of the larger system. Its name, directory, imports, and exports show where it fits. Start by reading the exports and related files first.

How it is used

Start from the exports list and related files. Those are the easiest clues for where this file fits into the system.

Expert explanation

Architecturally, this file intersects with general runtime concerns. It contains 860 lines, 27 detected imports, and 2 detected exports.

Important relationships

Detected exports

  • SANDBOX_NETWORK_ACCESS_TOOL_NAME
  • StructuredIO

Keywords

messagerequestresponseinputtoolpermissionhookresultpromiserequestid

Detected imports

  • bun:bundle
  • @modelcontextprotocol/sdk/types.js
  • crypto
  • src//types/message.js
  • src/entrypoints/agentSdkTypes.js
  • src/entrypoints/sdk/controlSchemas.js
  • src/entrypoints/sdk/controlTypes.js
  • src/hooks/useCanUseTool.js
  • src/Tool.js
  • src/types/hooks.js
  • src/utils/debug.js
  • src/utils/diagLogs.js
  • src/utils/errors.js
  • src/utils/permissions/PermissionPromptToolResultSchema.js
  • src/utils/permissions/PermissionResult.js
  • src/utils/permissions/permissions.js
  • src/utils/process.js
  • src/utils/slowOperations.js
  • zod/v4
  • ../utils/commandLifecycle.js
  • ../utils/controlMessageCompat.js
  • ../utils/hooks.js
  • ../utils/permissions/PermissionUpdate.js
  • ../utils/sessionState.js
  • ../utils/slowOperations.js
  • ../utils/stream.js
  • ./ndjsonSafeStringify.js

Source notes

This page embeds the full file contents. Small or leaf files are still indexed honestly instead of being over-explained.

Open parent directory

Full source

import { feature } from 'bun:bundle'
import type {
  ElicitResult,
  JSONRPCMessage,
} from '@modelcontextprotocol/sdk/types.js'
import { randomUUID } from 'crypto'
import type { AssistantMessage } from 'src//types/message.js'
import type {
  HookInput,
  HookJSONOutput,
  PermissionUpdate,
  SDKMessage,
  SDKUserMessage,
} from 'src/entrypoints/agentSdkTypes.js'
import { SDKControlElicitationResponseSchema } from 'src/entrypoints/sdk/controlSchemas.js'
import type {
  SDKControlRequest,
  SDKControlResponse,
  StdinMessage,
  StdoutMessage,
} from 'src/entrypoints/sdk/controlTypes.js'
import type { CanUseToolFn } from 'src/hooks/useCanUseTool.js'
import type { Tool, ToolUseContext } from 'src/Tool.js'
import { type HookCallback, hookJSONOutputSchema } from 'src/types/hooks.js'
import { logForDebugging } from 'src/utils/debug.js'
import { logForDiagnosticsNoPII } from 'src/utils/diagLogs.js'
import { AbortError } from 'src/utils/errors.js'
import {
  type Output as PermissionToolOutput,
  permissionPromptToolResultToPermissionDecision,
  outputSchema as permissionToolOutputSchema,
} from 'src/utils/permissions/PermissionPromptToolResultSchema.js'
import type {
  PermissionDecision,
  PermissionDecisionReason,
} from 'src/utils/permissions/PermissionResult.js'
import { hasPermissionsToUseTool } from 'src/utils/permissions/permissions.js'
import { writeToStdout } from 'src/utils/process.js'
import { jsonStringify } from 'src/utils/slowOperations.js'
import { z } from 'zod/v4'
import { notifyCommandLifecycle } from '../utils/commandLifecycle.js'
import { normalizeControlMessageKeys } from '../utils/controlMessageCompat.js'
import { executePermissionRequestHooks } from '../utils/hooks.js'
import {
  applyPermissionUpdates,
  persistPermissionUpdates,
} from '../utils/permissions/PermissionUpdate.js'
import {
  notifySessionStateChanged,
  type RequiresActionDetails,
  type SessionExternalMetadata,
} from '../utils/sessionState.js'
import { jsonParse } from '../utils/slowOperations.js'
import { Stream } from '../utils/stream.js'
import { ndjsonSafeStringify } from './ndjsonSafeStringify.js'

/**
 * Synthetic tool name used when forwarding sandbox network permission
 * requests via the can_use_tool control_request protocol. SDK hosts
 * see this as a normal tool permission prompt.
 */
export const SANDBOX_NETWORK_ACCESS_TOOL_NAME = 'SandboxNetworkAccess'

function serializeDecisionReason(
  reason: PermissionDecisionReason | undefined,
): string | undefined {
  if (!reason) {
    return undefined
  }

  if (
    (feature('BASH_CLASSIFIER') || feature('TRANSCRIPT_CLASSIFIER')) &&
    reason.type === 'classifier'
  ) {
    return reason.reason
  }
  switch (reason.type) {
    case 'rule':
    case 'mode':
    case 'subcommandResults':
    case 'permissionPromptTool':
      return undefined
    case 'hook':
    case 'asyncAgent':
    case 'sandboxOverride':
    case 'workingDir':
    case 'safetyCheck':
    case 'other':
      return reason.reason
  }
}

function buildRequiresActionDetails(
  tool: Tool,
  input: Record<string, unknown>,
  toolUseID: string,
  requestId: string,
): RequiresActionDetails {
  // Per-tool summary methods may throw on malformed input; permission
  // handling must not break because of a bad description.
  let description: string
  try {
    description =
      tool.getActivityDescription?.(input) ??
      tool.getToolUseSummary?.(input) ??
      tool.userFacingName(input)
  } catch {
    description = tool.name
  }
  return {
    tool_name: tool.name,
    action_description: description,
    tool_use_id: toolUseID,
    request_id: requestId,
    input,
  }
}

type PendingRequest<T> = {
  resolve: (result: T) => void
  reject: (error: unknown) => void
  schema?: z.Schema
  request: SDKControlRequest
}

/**
 * Provides a structured way to read and write SDK messages from stdio,
 * capturing the SDK protocol.
 */
// Maximum number of resolved tool_use IDs to track. Once exceeded, the oldest
// entry is evicted. This bounds memory in very long sessions while keeping
// enough history to catch duplicate control_response deliveries.
const MAX_RESOLVED_TOOL_USE_IDS = 1000

export class StructuredIO {
  readonly structuredInput: AsyncGenerator<StdinMessage | SDKMessage>
  private readonly pendingRequests = new Map<string, PendingRequest<unknown>>()

  // CCR external_metadata read back on worker start; null when the
  // transport doesn't restore. Assigned by RemoteIO.
  restoredWorkerState: Promise<SessionExternalMetadata | null> =
    Promise.resolve(null)

  private inputClosed = false
  private unexpectedResponseCallback?: (
    response: SDKControlResponse,
  ) => Promise<void>

  // Tracks tool_use IDs that have been resolved through the normal permission
  // flow (or aborted by a hook). When a duplicate control_response arrives
  // after the original was already handled, this Set prevents the orphan
  // handler from re-processing it — which would push duplicate assistant
  // messages into mutableMessages and cause a 400 "tool_use ids must be unique"
  // error from the API.
  private readonly resolvedToolUseIds = new Set<string>()
  private prependedLines: string[] = []
  private onControlRequestSent?: (request: SDKControlRequest) => void
  private onControlRequestResolved?: (requestId: string) => void

  // sendRequest() and print.ts both enqueue here; the drain loop is the
  // only writer. Prevents control_request from overtaking queued stream_events.
  readonly outbound = new Stream<StdoutMessage>()

  constructor(
    private readonly input: AsyncIterable<string>,
    private readonly replayUserMessages?: boolean,
  ) {
    this.input = input
    this.structuredInput = this.read()
  }

  /**
   * Records a tool_use ID as resolved so that late/duplicate control_response
   * messages for the same tool are ignored by the orphan handler.
   */
  private trackResolvedToolUseId(request: SDKControlRequest): void {
    if (request.request.subtype === 'can_use_tool') {
      this.resolvedToolUseIds.add(request.request.tool_use_id)
      if (this.resolvedToolUseIds.size > MAX_RESOLVED_TOOL_USE_IDS) {
        // Evict the oldest entry (Sets iterate in insertion order)
        const first = this.resolvedToolUseIds.values().next().value
        if (first !== undefined) {
          this.resolvedToolUseIds.delete(first)
        }
      }
    }
  }

  /** Flush pending internal events. No-op for non-remote IO. Overridden by RemoteIO. */
  flushInternalEvents(): Promise<void> {
    return Promise.resolve()
  }

  /** Internal-event queue depth. Overridden by RemoteIO; zero otherwise. */
  get internalEventsPending(): number {
    return 0
  }

  /**
   * Queue a user turn to be yielded before the next message from this.input.
   * Works before iteration starts and mid-stream — read() re-checks
   * prependedLines between each yielded message.
   */
  prependUserMessage(content: string): void {
    this.prependedLines.push(
      jsonStringify({
        type: 'user',
        session_id: '',
        message: { role: 'user', content },
        parent_tool_use_id: null,
      } satisfies SDKUserMessage) + '\n',
    )
  }

  private async *read() {
    let content = ''

    // Called once before for-await (an empty this.input otherwise skips the
    // loop body entirely), then again per block. prependedLines re-check is
    // inside the while so a prepend pushed between two messages in the SAME
    // block still lands first.
    const splitAndProcess = async function* (this: StructuredIO) {
      for (;;) {
        if (this.prependedLines.length > 0) {
          content = this.prependedLines.join('') + content
          this.prependedLines = []
        }
        const newline = content.indexOf('\n')
        if (newline === -1) break
        const line = content.slice(0, newline)
        content = content.slice(newline + 1)
        const message = await this.processLine(line)
        if (message) {
          logForDiagnosticsNoPII('info', 'cli_stdin_message_parsed', {
            type: message.type,
          })
          yield message
        }
      }
    }.bind(this)

    yield* splitAndProcess()

    for await (const block of this.input) {
      content += block
      yield* splitAndProcess()
    }
    if (content) {
      const message = await this.processLine(content)
      if (message) {
        yield message
      }
    }
    this.inputClosed = true
    for (const request of this.pendingRequests.values()) {
      // Reject all pending requests if the input stream
      request.reject(
        new Error('Tool permission stream closed before response received'),
      )
    }
  }

  getPendingPermissionRequests() {
    return Array.from(this.pendingRequests.values())
      .map(entry => entry.request)
      .filter(pr => pr.request.subtype === 'can_use_tool')
  }

  setUnexpectedResponseCallback(
    callback: (response: SDKControlResponse) => Promise<void>,
  ): void {
    this.unexpectedResponseCallback = callback
  }

  /**
   * Inject a control_response message to resolve a pending permission request.
   * Used by the bridge to feed permission responses from claude.ai into the
   * SDK permission flow.
   *
   * Also sends a control_cancel_request to the SDK consumer so its canUseTool
   * callback is aborted via the signal — otherwise the callback hangs.
   */
  injectControlResponse(response: SDKControlResponse): void {
    const requestId = response.response?.request_id
    if (!requestId) return
    const request = this.pendingRequests.get(requestId)
    if (!request) return
    this.trackResolvedToolUseId(request.request)
    this.pendingRequests.delete(requestId)
    // Cancel the SDK consumer's canUseTool callback — the bridge won.
    void this.write({
      type: 'control_cancel_request',
      request_id: requestId,
    })
    if (response.response.subtype === 'error') {
      request.reject(new Error(response.response.error))
    } else {
      const result = response.response.response
      if (request.schema) {
        try {
          request.resolve(request.schema.parse(result))
        } catch (error) {
          request.reject(error)
        }
      } else {
        request.resolve({})
      }
    }
  }

  /**
   * Register a callback invoked whenever a can_use_tool control_request
   * is written to stdout. Used by the bridge to forward permission
   * requests to claude.ai.
   */
  setOnControlRequestSent(
    callback: ((request: SDKControlRequest) => void) | undefined,
  ): void {
    this.onControlRequestSent = callback
  }

  /**
   * Register a callback invoked when a can_use_tool control_response arrives
   * from the SDK consumer (via stdin). Used by the bridge to cancel the
   * stale permission prompt on claude.ai when the SDK consumer wins the race.
   */
  setOnControlRequestResolved(
    callback: ((requestId: string) => void) | undefined,
  ): void {
    this.onControlRequestResolved = callback
  }

  private async processLine(
    line: string,
  ): Promise<StdinMessage | SDKMessage | undefined> {
    // Skip empty lines (e.g. from double newlines in piped stdin)
    if (!line) {
      return undefined
    }
    try {
      const message = normalizeControlMessageKeys(jsonParse(line)) as
        | StdinMessage
        | SDKMessage
      if (message.type === 'keep_alive') {
        // Silently ignore keep-alive messages
        return undefined
      }
      if (message.type === 'update_environment_variables') {
        // Apply environment variable updates directly to process.env.
        // Used by bridge session runner for auth token refresh
        // (CLAUDE_CODE_SESSION_ACCESS_TOKEN) which must be readable
        // by the REPL process itself, not just child Bash commands.
        const keys = Object.keys(message.variables)
        for (const [key, value] of Object.entries(message.variables)) {
          process.env[key] = value
        }
        logForDebugging(
          `[structuredIO] applied update_environment_variables: ${keys.join(', ')}`,
        )
        return undefined
      }
      if (message.type === 'control_response') {
        // Close lifecycle for every control_response, including duplicates
        // and orphans — orphans don't yield to print.ts's main loop, so this
        // is the only path that sees them. uuid is server-injected into the
        // payload.
        const uuid =
          'uuid' in message && typeof message.uuid === 'string'
            ? message.uuid
            : undefined
        if (uuid) {
          notifyCommandLifecycle(uuid, 'completed')
        }
        const request = this.pendingRequests.get(message.response.request_id)
        if (!request) {
          // Check if this tool_use was already resolved through the normal
          // permission flow. Duplicate control_response deliveries (e.g. from
          // WebSocket reconnects) arrive after the original was handled, and
          // re-processing them would push duplicate assistant messages into
          // the conversation, causing API 400 errors.
          const responsePayload =
            message.response.subtype === 'success'
              ? message.response.response
              : undefined
          const toolUseID = responsePayload?.toolUseID
          if (
            typeof toolUseID === 'string' &&
            this.resolvedToolUseIds.has(toolUseID)
          ) {
            logForDebugging(
              `Ignoring duplicate control_response for already-resolved toolUseID=${toolUseID} request_id=${message.response.request_id}`,
            )
            return undefined
          }
          if (this.unexpectedResponseCallback) {
            await this.unexpectedResponseCallback(message)
          }
          return undefined // Ignore responses for requests we don't know about
        }
        this.trackResolvedToolUseId(request.request)
        this.pendingRequests.delete(message.response.request_id)
        // Notify the bridge when the SDK consumer resolves a can_use_tool
        // request, so it can cancel the stale permission prompt on claude.ai.
        if (
          request.request.request.subtype === 'can_use_tool' &&
          this.onControlRequestResolved
        ) {
          this.onControlRequestResolved(message.response.request_id)
        }

        if (message.response.subtype === 'error') {
          request.reject(new Error(message.response.error))
          return undefined
        }
        const result = message.response.response
        if (request.schema) {
          try {
            request.resolve(request.schema.parse(result))
          } catch (error) {
            request.reject(error)
          }
        } else {
          request.resolve({})
        }
        // Propagate control responses when replay is enabled
        if (this.replayUserMessages) {
          return message
        }
        return undefined
      }
      if (
        message.type !== 'user' &&
        message.type !== 'control_request' &&
        message.type !== 'assistant' &&
        message.type !== 'system'
      ) {
        logForDebugging(`Ignoring unknown message type: ${message.type}`, {
          level: 'warn',
        })
        return undefined
      }
      if (message.type === 'control_request') {
        if (!message.request) {
          exitWithMessage(`Error: Missing request on control_request`)
        }
        return message
      }
      if (message.type === 'assistant' || message.type === 'system') {
        return message
      }
      if (message.message.role !== 'user') {
        exitWithMessage(
          `Error: Expected message role 'user', got '${message.message.role}'`,
        )
      }
      return message
    } catch (error) {
      // biome-ignore lint/suspicious/noConsole:: intentional console output
      console.error(`Error parsing streaming input line: ${line}: ${error}`)
      // eslint-disable-next-line custom-rules/no-process-exit
      process.exit(1)
    }
  }

  async write(message: StdoutMessage): Promise<void> {
    writeToStdout(ndjsonSafeStringify(message) + '\n')
  }

  private async sendRequest<Response>(
    request: SDKControlRequest['request'],
    schema: z.Schema,
    signal?: AbortSignal,
    requestId: string = randomUUID(),
  ): Promise<Response> {
    const message: SDKControlRequest = {
      type: 'control_request',
      request_id: requestId,
      request,
    }
    if (this.inputClosed) {
      throw new Error('Stream closed')
    }
    if (signal?.aborted) {
      throw new Error('Request aborted')
    }
    this.outbound.enqueue(message)
    if (request.subtype === 'can_use_tool' && this.onControlRequestSent) {
      this.onControlRequestSent(message)
    }
    const aborted = () => {
      this.outbound.enqueue({
        type: 'control_cancel_request',
        request_id: requestId,
      })
      // Immediately reject the outstanding promise, without
      // waiting for the host to acknowledge the cancellation.
      const request = this.pendingRequests.get(requestId)
      if (request) {
        // Track the tool_use ID as resolved before rejecting, so that a
        // late response from the host is ignored by the orphan handler.
        this.trackResolvedToolUseId(request.request)
        request.reject(new AbortError())
      }
    }
    if (signal) {
      signal.addEventListener('abort', aborted, {
        once: true,
      })
    }
    try {
      return await new Promise<Response>((resolve, reject) => {
        this.pendingRequests.set(requestId, {
          request: {
            type: 'control_request',
            request_id: requestId,
            request,
          },
          resolve: result => {
            resolve(result as Response)
          },
          reject,
          schema,
        })
      })
    } finally {
      if (signal) {
        signal.removeEventListener('abort', aborted)
      }
      this.pendingRequests.delete(requestId)
    }
  }

  createCanUseTool(
    onPermissionPrompt?: (details: RequiresActionDetails) => void,
  ): CanUseToolFn {
    return async (
      tool: Tool,
      input: { [key: string]: unknown },
      toolUseContext: ToolUseContext,
      assistantMessage: AssistantMessage,
      toolUseID: string,
      forceDecision?: PermissionDecision,
    ): Promise<PermissionDecision> => {
      const mainPermissionResult =
        forceDecision ??
        (await hasPermissionsToUseTool(
          tool,
          input,
          toolUseContext,
          assistantMessage,
          toolUseID,
        ))
      // If the tool is allowed or denied, return the result
      if (
        mainPermissionResult.behavior === 'allow' ||
        mainPermissionResult.behavior === 'deny'
      ) {
        return mainPermissionResult
      }

      // Run PermissionRequest hooks in parallel with the SDK permission
      // prompt.  In the terminal CLI, hooks race against the interactive
      // prompt so that e.g. a hook with --delay 20 doesn't block the UI.
      // We need the same behavior here: the SDK host (VS Code, etc.) shows
      // its permission dialog immediately while hooks run in the background.
      // Whichever resolves first wins; the loser is cancelled/ignored.

      // AbortController used to cancel the SDK request if a hook decides first
      const hookAbortController = new AbortController()
      const parentSignal = toolUseContext.abortController.signal
      // Forward parent abort to our local controller
      const onParentAbort = () => hookAbortController.abort()
      parentSignal.addEventListener('abort', onParentAbort, { once: true })

      try {
        // Start the hook evaluation (runs in background)
        const hookPromise = executePermissionRequestHooksForSDK(
          tool.name,
          toolUseID,
          input,
          toolUseContext,
          mainPermissionResult.suggestions,
        ).then(decision => ({ source: 'hook' as const, decision }))

        // Start the SDK permission prompt immediately (don't wait for hooks)
        const requestId = randomUUID()
        onPermissionPrompt?.(
          buildRequiresActionDetails(tool, input, toolUseID, requestId),
        )
        const sdkPromise = this.sendRequest<PermissionToolOutput>(
          {
            subtype: 'can_use_tool',
            tool_name: tool.name,
            input,
            permission_suggestions: mainPermissionResult.suggestions,
            blocked_path: mainPermissionResult.blockedPath,
            decision_reason: serializeDecisionReason(
              mainPermissionResult.decisionReason,
            ),
            tool_use_id: toolUseID,
            agent_id: toolUseContext.agentId,
          },
          permissionToolOutputSchema(),
          hookAbortController.signal,
          requestId,
        ).then(result => ({ source: 'sdk' as const, result }))

        // Race: hook completion vs SDK prompt response.
        // The hook promise always resolves (never rejects), returning
        // undefined if no hook made a decision.
        const winner = await Promise.race([hookPromise, sdkPromise])

        if (winner.source === 'hook') {
          if (winner.decision) {
            // Hook decided — abort the pending SDK request.
            // Suppress the expected AbortError rejection from sdkPromise.
            sdkPromise.catch(() => {})
            hookAbortController.abort()
            return winner.decision
          }
          // Hook passed through (no decision) — wait for the SDK prompt
          const sdkResult = await sdkPromise
          return permissionPromptToolResultToPermissionDecision(
            sdkResult.result,
            tool,
            input,
            toolUseContext,
          )
        }

        // SDK prompt responded first — use its result (hook still running
        // in background but its result will be ignored)
        return permissionPromptToolResultToPermissionDecision(
          winner.result,
          tool,
          input,
          toolUseContext,
        )
      } catch (error) {
        return permissionPromptToolResultToPermissionDecision(
          {
            behavior: 'deny',
            message: `Tool permission request failed: ${error}`,
            toolUseID,
          },
          tool,
          input,
          toolUseContext,
        )
      } finally {
        // Only transition back to 'running' if no other permission prompts
        // are pending (concurrent tool execution can have multiple in-flight).
        if (this.getPendingPermissionRequests().length === 0) {
          notifySessionStateChanged('running')
        }
        parentSignal.removeEventListener('abort', onParentAbort)
      }
    }
  }

  createHookCallback(callbackId: string, timeout?: number): HookCallback {
    return {
      type: 'callback',
      timeout,
      callback: async (
        input: HookInput,
        toolUseID: string | null,
        abort: AbortSignal | undefined,
      ): Promise<HookJSONOutput> => {
        try {
          const result = await this.sendRequest<HookJSONOutput>(
            {
              subtype: 'hook_callback',
              callback_id: callbackId,
              input,
              tool_use_id: toolUseID || undefined,
            },
            hookJSONOutputSchema(),
            abort,
          )
          return result
        } catch (error) {
          // biome-ignore lint/suspicious/noConsole:: intentional console output
          console.error(`Error in hook callback ${callbackId}:`, error)
          return {}
        }
      },
    }
  }

  /**
   * Sends an elicitation request to the SDK consumer and returns the response.
   */
  async handleElicitation(
    serverName: string,
    message: string,
    requestedSchema?: Record<string, unknown>,
    signal?: AbortSignal,
    mode?: 'form' | 'url',
    url?: string,
    elicitationId?: string,
  ): Promise<ElicitResult> {
    try {
      const result = await this.sendRequest<ElicitResult>(
        {
          subtype: 'elicitation',
          mcp_server_name: serverName,
          message,
          mode,
          url,
          elicitation_id: elicitationId,
          requested_schema: requestedSchema,
        },
        SDKControlElicitationResponseSchema(),
        signal,
      )
      return result
    } catch {
      return { action: 'cancel' as const }
    }
  }

  /**
   * Creates a SandboxAskCallback that forwards sandbox network permission
   * requests to the SDK host as can_use_tool control_requests.
   *
   * This piggybacks on the existing can_use_tool protocol with a synthetic
   * tool name so that SDK hosts (VS Code, CCR, etc.) can prompt the user
   * for network access without requiring a new protocol subtype.
   */
  createSandboxAskCallback(): (hostPattern: {
    host: string
    port?: number
  }) => Promise<boolean> {
    return async (hostPattern): Promise<boolean> => {
      try {
        const result = await this.sendRequest<PermissionToolOutput>(
          {
            subtype: 'can_use_tool',
            tool_name: SANDBOX_NETWORK_ACCESS_TOOL_NAME,
            input: { host: hostPattern.host },
            tool_use_id: randomUUID(),
            description: `Allow network connection to ${hostPattern.host}?`,
          },
          permissionToolOutputSchema(),
        )
        return result.behavior === 'allow'
      } catch {
        // If the request fails (stream closed, abort, etc.), deny the connection
        return false
      }
    }
  }

  /**
   * Sends an MCP message to an SDK server and waits for the response
   */
  async sendMcpMessage(
    serverName: string,
    message: JSONRPCMessage,
  ): Promise<JSONRPCMessage> {
    const response = await this.sendRequest<{ mcp_response: JSONRPCMessage }>(
      {
        subtype: 'mcp_message',
        server_name: serverName,
        message,
      },
      z.object({
        mcp_response: z.any() as z.Schema<JSONRPCMessage>,
      }),
    )
    return response.mcp_response
  }
}

function exitWithMessage(message: string): never {
  // biome-ignore lint/suspicious/noConsole:: intentional console output
  console.error(message)
  // eslint-disable-next-line custom-rules/no-process-exit
  process.exit(1)
}

/**
 * Execute PermissionRequest hooks and return a decision if one is made.
 * Returns undefined if no hook made a decision.
 */
async function executePermissionRequestHooksForSDK(
  toolName: string,
  toolUseID: string,
  input: Record<string, unknown>,
  toolUseContext: ToolUseContext,
  suggestions: PermissionUpdate[] | undefined,
): Promise<PermissionDecision | undefined> {
  const appState = toolUseContext.getAppState()
  const permissionMode = appState.toolPermissionContext.mode

  // Iterate directly over the generator instead of using `all`
  const hookGenerator = executePermissionRequestHooks(
    toolName,
    toolUseID,
    input,
    toolUseContext,
    permissionMode,
    suggestions,
    toolUseContext.abortController.signal,
  )

  for await (const hookResult of hookGenerator) {
    if (
      hookResult.permissionRequestResult &&
      (hookResult.permissionRequestResult.behavior === 'allow' ||
        hookResult.permissionRequestResult.behavior === 'deny')
    ) {
      const decision = hookResult.permissionRequestResult
      if (decision.behavior === 'allow') {
        const finalInput = decision.updatedInput || input

        // Apply permission updates if provided by hook ("always allow")
        const permissionUpdates = decision.updatedPermissions ?? []
        if (permissionUpdates.length > 0) {
          persistPermissionUpdates(permissionUpdates)
          const currentAppState = toolUseContext.getAppState()
          const updatedContext = applyPermissionUpdates(
            currentAppState.toolPermissionContext,
            permissionUpdates,
          )
          // Update permission context via setAppState
          toolUseContext.setAppState(prev => {
            if (prev.toolPermissionContext === updatedContext) return prev
            return { ...prev, toolPermissionContext: updatedContext }
          })
        }

        return {
          behavior: 'allow',
          updatedInput: finalInput,
          userModified: false,
          decisionReason: {
            type: 'hook',
            hookName: 'PermissionRequest',
          },
        }
      } else {
        // Hook denied the permission
        return {
          behavior: 'deny',
          message:
            decision.message || 'Permission denied by PermissionRequest hook',
          decisionReason: {
            type: 'hook',
            hookName: 'PermissionRequest',
          },
        }
      }
    }
  }

  return undefined
}