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Summary

The Inputs namespace contains classes for deserializing JSON data that Claude Code sends to hooks via stdin. Each hook event type has a corresponding input class.

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Input Classes

ClassHook EventDescription
PreToolUseHookInput<T>PreToolUseReceived before a tool executes
PostToolUseHookInput<T,R>PostToolUseReceived after a tool completes
PermissionRequestHookInput<T>PermissionRequestReceived when permission is requested
UserPromptSubmitHookInputUserPromptSubmitReceived when user submits a prompt
StopHookInputStopReceived when Claude finishes responding
SubagentStopHookInputSubagentStopReceived when a subagent completes
NotificationHookInputNotificationReceived for notifications
SessionStartHookInputSessionStartReceived when a session starts
SessionEndHookInputSessionEndReceived when a session ends
PreCompactHookInputPreCompactReceived before context compaction
All input classes inherit from HookInputBase which provides common properties like SessionId, TranscriptPath, and CurrentWorkingDirectory.

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Usage

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Deserializing Hook Input

Use ClaudeHooksSerializer to deserialize input from stdin: 
// For PreToolUse hooks
var input = ClaudeHooksSerializer.DeserializePreToolUseInput(Console.In.ReadToEnd());
Console.WriteLine($"Tool: {input?.ToolName}");
Console.WriteLine($"Session: {input?.SessionId}");

// For strongly-typed tool input (requires custom JsonSerializerContext)
var typedInput = ClaudeHooksSerializer.DeserializePreToolUseInput<MyToolInput>(
    json, MyJsonContext.Default.PreToolUseHookInputMyToolInput);

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Common Base Properties

All inputs include these properties from HookInputBase:
  • SessionId - Unique session identifier
  • TranscriptPath - Path to conversation transcript
  • CurrentWorkingDirectory - Active working directory
  • PermissionMode - Current permission mode
  • HookEventName - The event that triggered this hook

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Types

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Classes

NameSummary
HookInputBaseBase class containing common fields present in all hook inputs. All hooks receive these fields via JSON through stdin.
ToolHookInputBaseBase class for tool-related hook inputs that contain tool name, input, and use ID. Used as a base for PreToolUse and PostToolUse hook inputs.
NotificationHookInputRepresents the input received by a Notification hook. This hook runs when Claude Code sends notifications.
PermissionRequestHookInputRepresents the input received by a PermissionRequest hook. This hook runs when a permission dialog is shown and can automatically allow or deny permissions.
PostToolUseHookInputRepresents the input received by a PostToolUse hook. This hook runs after tool calls complete and includes the tool’s response.
PreCompactHookInputRepresents the input received by a PreCompact hook. This hook runs before a compact operation.
PreToolUseHookInputRepresents the input received by a PreToolUse hook. This hook runs before tool calls are executed and can block or modify them.
SessionEndHookInputRepresents the input received by a SessionEnd hook. This hook runs when a Claude Code session ends.
SessionStartHookInputRepresents the input received by a SessionStart hook. This hook runs when Claude Code starts a new session or resumes one.
StopHookInputRepresents the input received by a Stop hook. This hook runs when Claude Code finishes responding.
SubagentStopHookInputRepresents the input received by a SubagentStop hook. This hook runs when subagent tasks complete.
UserPromptSubmitHookInputRepresents the input received by a UserPromptSubmit hook. This hook runs when the user submits a prompt, before Claude processes it.