Tool Schemas | Claude Code

▾

Bash

{
  "stdout": "hello",
  "stderr": "",
  "interrupted": false,
  "isImage": false
}

Background mode adds:

"backgroundTaskId": "833aa6"

▾

BashOutput

{
  "shellId": "833aa6",
  "command": "sleep 2 && echo done",
  "status": "completed",
  "exitCode": 0,
  "stdout": "done",
  "stderr": "",
  "stdoutLines": 1,
  "stderrLines": 1,
  "timestamp": "..."
}

Status can be "completed" or "running".

▾

Read

{
  "type": "text",
  "file": {
    "filePath": "...",
    "content": "...",
    "numLines": 10,
    "startLine": 1,
    "totalLines": 135
  }
}

▾

Write

{
  "type": "create",
  "filePath": "...",
  "content": "...",
  "structuredPatch": [],
  "originalFile": null
}

▾

Edit

{
  "filePath": "...",
  "oldString": "...",
  "newString": "...",
  "originalFile": "...",
  "structuredPatch": [
    {
      "oldStart": 1,
      "oldLines": 2,
      "newStart": 1,
      "newLines": 3,
      "lines": ["+new", " unchanged"]
    }
  ],
  "userModified": false,
  "replaceAll": false
}

Includes unified diff in structuredPatch.

▾

Glob

{
  "filenames": [
    "/path/to/file1.md",
    "/path/to/file2.md"
  ],
  "durationMs": 455,
  "numFiles": 4,
  "truncated": false
}

▾

Grep

{
  "mode": "content",
  "numFiles": 0,
  "filenames": [],
  "content": "file.ts:42:matching line",
  "numLines": 1,
  "appliedLimit": 100
}

Mode can be "content", "files_with_matches", or "count".

▾

WebFetch

{
  "bytes": 513,
  "code": 200,
  "codeText": "OK",
  "result": "AI-processed content...",
  "durationMs": 1468,
  "url": "https://..."
}

▾

WebSearch

{
  "query": "search query",
  "results": [
    {
      "tool_use_id": "...",
      "content": [
        {
          "title": "...",
          "url": "..."
        }
      ]
    }
  ],
  "durationSeconds": 21.4
}

▾

TodoWrite

{
  "oldTodos": [
    {
      "content": "Task A",
      "status": "pending",
      "activeForm": "..."
    }
  ],
  "newTodos": [
    {
      "content": "Task A",
      "status": "completed",
      "activeForm": "..."
    }
  ]
}

Shows before/after state. Deletion = item missing from newTodos.

▾

Task (Sub-Agents)

{
  "status": "completed",
  "prompt": "...",
  "agentId": "4b38c8b3",
  "content": [
    {
      "type": "text",
      "text": "Agent response..."
    }
  ],
  "totalDurationMs": 6457,
  "totalTokens": 16151,
  "totalToolUseCount": 2,
  "usage": {...}
}

Sub-agent notes

parent_tool_use_id links sub-agent messages to parent Task
Sub-agents canNOT spawn their own sub-agents (max depth = 1)
Available agent types: general-purpose, Explore, Plan, claude-code-guide, statusline-setup

▾

Not Captured

These require special conditions:

KillShell — needs active background process
NotebookEdit — needs .ipynb file
AskUserQuestion — blocked in headless
Skill/SlashCommand — needs plugin setup
EnterPlanMode/ExitPlanMode — mode transitions