# Join files

- Human page: https://happytails.ai/en/archive-tools/join-files/
- Markdown: https://happytails.ai/en/archive-tools/join-files.md
- Structured JSON: https://happytails.ai/agents/en/archive-tools/join-files/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `join-files` |
| Category | archive-tools |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Use the visible action or interactive controls. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | /api/v1/tools/join-files/run |
| Browser-agent interface | run_current_tool |

### Implementation notes

Joins raw parts in filename order, not separate PDF/video documents.

### Inputs and settings

No free-text input is required. Use the file inputs and/or settings below.

Accepted browser files: `See implementation notes`. Multiple files are supported.

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `name` | Output filename | text | "joined-file.bin" |  |

### HTTP contract

API calls process supplied data on the server. The website origin is `https://happytails.ai`. Server API hosting is not connected on the public website yet. Use your local server origin to test these requests.

```http
POST https://happytails.ai/api/v1/tools/join-files/run
Content-Type: application/json
```

[Detailed operation reference](https://happytails.ai/en/api/tools/join-files.md) · [Shared API guide](https://happytails.ai/en/api.md)

#### Limits

| Limit | Value |
| --- | --- |
| request_bytes | 8388608 |
| input_characters | 1000000 |
| files_bytes | 5242880 |
| max_files | 20 |
| timeout_seconds | 12 |

#### Complete input schema

```json
{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "input": {
      "type": "string",
      "maxLength": 1000000,
      "default": "",
      "description": "Plain text input. File tools use files instead unless otherwise documented."
    },
    "options": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "name": {
          "type": "string",
          "description": "Output filename",
          "default": "joined-file.bin"
        }
      }
    },
    "files": {
      "type": "array",
      "maxItems": 20,
      "items": {
        "type": "object",
        "required": [
          "name",
          "base64"
        ],
        "additionalProperties": false,
        "properties": {
          "name": {
            "type": "string",
            "maxLength": 200,
            "description": "Filename only, no path."
          },
          "mime": {
            "type": "string",
            "maxLength": 150
          },
          "bytes": {
            "type": "integer",
            "minimum": 0,
            "description": "Optional decoded byte count; must match content if supplied."
          },
          "base64": {
            "type": "string",
            "contentEncoding": "base64",
            "description": "File bytes as padded base64. Use the tool-specific limits.files_bytes value for the total decoded input size."
          }
        }
      }
    }
  }
}
```

#### Complete output schema

```json
{
  "type": "object",
  "required": [
    "tool",
    "result"
  ],
  "properties": {
    "tool": {
      "type": "string"
    },
    "result": {
      "type": "object",
      "required": [
        "text",
        "files"
      ],
      "properties": {
        "text": {
          "type": [
            "string",
            "null"
          ]
        },
        "data": {
          "description": "Parsed JSON when the textual result is JSON."
        },
        "name": {
          "type": "string"
        },
        "mime": {
          "type": "string"
        },
        "files": {
          "type": "array",
          "items": {
            "type": "object",
            "required": [
              "name",
              "mime",
              "bytes",
              "base64"
            ],
            "properties": {
              "name": {
                "type": "string"
              },
              "mime": {
                "type": "string"
              },
              "bytes": {
                "type": "integer"
              },
              "base64": {
                "type": "string",
                "contentEncoding": "base64"
              }
            }
          }
        }
      }
    }
  }
}
```

#### Error and retry handling

Failures return a non-200 status and `error.code` plus `error.message`. Correct invalid input before retrying; retry server-busy responses with bounded backoff. Returned files contain Base64 data, not persistent download URLs. Decode and inspect the output before treating conversion as successful. See the shared API guide for the complete status and timeout rules.

### Browser-agent workflow

1. Open the human page in a browser that supports WebMCP.
2. Discover the interface exposed by that page; use its actual schema.
3. Select files on the page first when the tool requires files.
4. Call `run_current_tool` with valid input and settings.
5. Inspect the returned result or error and the displayed output. Retrieve files from the displayed download links.

Calls do not automatically copy or download results. Browser permissions still apply. Interface availability alone is not proof of successful execution.

### Planning specification

Require correct ordered binary parts; no claim to merge arbitrary documents.

This describes intended requirements. Use the implementation notes, interface schema and observed output to determine current support.

### Complete machine-readable capability record

```json
{
  "id": "join-files",
  "category": "archive-tools",
  "built": true,
  "requirements": "Require correct ordered binary parts; no claim to merge arbitrary documents.",
  "implementation": {
    "fields": [
      {
        "key": "name",
        "label": "Output filename",
        "value": "joined-file.bin",
        "type": "text"
      }
    ],
    "files": true,
    "multiple": true,
    "input": false,
    "note": "Joins raw parts in filename order, not separate PDF/video documents.",
    "experience": {
      "automatic": false,
      "single": false,
      "label": "Your text",
      "placeholder": "Type or paste your input…",
      "help": "Up to 1,000,000 characters. Review the settings before running.",
      "action": null
    },
    "mode": "explicit",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/join-files/run",
  "api": {
    "id": "join-files",
    "name": "Join files",
    "category": "archive-tools",
    "description": "Require correct ordered binary parts.",
    "notes": "Joins raw parts in filename order, not separate PDF/video documents.",
    "human_path": "/en/archive-tools/join-files/",
    "method": "POST",
    "endpoint": "/api/v1/tools/join-files/run",
    "schema_url": "/api/v1/tools/join-files",
    "input_schema": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "input": {
          "type": "string",
          "maxLength": 1000000,
          "default": "",
          "description": "Plain text input. File tools use files instead unless otherwise documented."
        },
        "options": {
          "type": "object",
          "additionalProperties": false,
          "properties": {
            "name": {
              "type": "string",
              "description": "Output filename",
              "default": "joined-file.bin"
            }
          }
        },
        "files": {
          "type": "array",
          "maxItems": 20,
          "items": {
            "type": "object",
            "required": [
              "name",
              "base64"
            ],
            "additionalProperties": false,
            "properties": {
              "name": {
                "type": "string",
                "maxLength": 200,
                "description": "Filename only, no path."
              },
              "mime": {
                "type": "string",
                "maxLength": 150
              },
              "bytes": {
                "type": "integer",
                "minimum": 0,
                "description": "Optional decoded byte count; must match content if supplied."
              },
              "base64": {
                "type": "string",
                "contentEncoding": "base64",
                "description": "File bytes as padded base64. Use the tool-specific limits.files_bytes value for the total decoded input size."
              }
            }
          }
        }
      }
    },
    "output_schema": {
      "type": "object",
      "required": [
        "tool",
        "result"
      ],
      "properties": {
        "tool": {
          "type": "string"
        },
        "result": {
          "type": "object",
          "required": [
            "text",
            "files"
          ],
          "properties": {
            "text": {
              "type": [
                "string",
                "null"
              ]
            },
            "data": {
              "description": "Parsed JSON when the textual result is JSON."
            },
            "name": {
              "type": "string"
            },
            "mime": {
              "type": "string"
            },
            "files": {
              "type": "array",
              "items": {
                "type": "object",
                "required": [
                  "name",
                  "mime",
                  "bytes",
                  "base64"
                ],
                "properties": {
                  "name": {
                    "type": "string"
                  },
                  "mime": {
                    "type": "string"
                  },
                  "bytes": {
                    "type": "integer"
                  },
                  "base64": {
                    "type": "string",
                    "contentEncoding": "base64"
                  }
                }
              }
            }
          }
        }
      }
    },
    "processing": "Server; same transformation code as browser tools",
    "limits": {
      "request_bytes": 8388608,
      "input_characters": 1000000,
      "files_bytes": 5242880,
      "max_files": 20,
      "timeout_seconds": 12
    }
  },
  "agent_processing": "Server; same transformation code as browser tools",
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}
```

## Page guide

Require correct ordered binary parts.

## Useful next steps

- [Split file](https://happytails.ai/en/archive-tools/split-file/): Chunk sizes, filenames and reconstruction instructions. ([Markdown](https://happytails.ai/en/archive-tools/split-file.md))

- [Bulk rename](https://happytails.ai/en/archive-tools/bulk-rename/): Preview naming rules and collisions. ([Markdown](https://happytails.ai/en/archive-tools/bulk-rename.md))

## How to use Join files

1. Choose one or more files in a supported format.
2. Review the settings, then choose Run Join files.
3. Review the result, then use Copy result or a download link when available.

## Working with join files

Archives package files together, sometimes with compression. The best format depends on compatibility, desired size and whether passwords or additional metadata must be retained. Extracting an archive and converting it into another archive are separate tasks.

## Common questions

### Will recompressing an archive always reduce its size?

No. Already compressed media and existing archives may save little or even grow slightly. Compression method and content type both affect the result.

### Does successful extraction prove a file is safe?

No. An archive can contain harmful or misleading files. Extraction establishes that the contents can be read, not that those contents should be opened or executed.

Continue your workflow: [Split file](https://happytails.ai/en/archive-tools/split-file/), [Bulk rename](https://happytails.ai/en/archive-tools/bulk-rename/).