# read_file

Read the complete contents of a file as text. DEPRECATED: Use read_text_file instead.

Agent View of the PolicyLayer registry record for `read_file`. HTML page: https://policylayer.com/tools/filesystem/read-file

## Facts

- Tool: `read_file`
- Server: Filesystem (`@modelcontextprotocol/server-filesystem`) — https://policylayer.com/tools/filesystem.md
- Install: `npx -y @modelcontextprotocol/server-filesystem`
- Homepage: https://github.com/modelcontextprotocol/server-filesystem
- Risk category: Read (Low risk)
- Registry record: grade D, identity verified
- Server rate-limited: no
- Parameters: 3 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `head` | number | no | If provided, returns only the first N lines of the file |
| `path` | string | yes |  |
| `tail` | number | no | If provided, returns only the last N lines of the file |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "read_file",
    "arguments": {
      "path": "<path>"
    }
  }
}
```

## Why read_file is rated Low

This tool retrieves file contents without creating, modifying, deleting, or executing operations. It is purely a read operation with minimal blast radius—the only risk would be unauthorized access to sensitive file contents, but that depends on access controls external to the tool itself.

From the tool's own definition: "Tool name is 'read_file' and description states 'Read the complete contents of a file as text'. The verb 'read' indicates data retrieval with no modification or side effects."

Risk signals: Accepts file system path (path)

## Use case

AI agents call read_file to retrieve information from Filesystem without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Filesystem:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "read_file": {}
  }
}
```

## Other tools on Filesystem (13)

- `directory_tree` — Read — https://policylayer.com/tools/filesystem/directory-tree.md
- `get_file_info` — Read — https://policylayer.com/tools/filesystem/get-file-info.md
- `list_allowed_directories` — Read — https://policylayer.com/tools/filesystem/list-allowed-directories.md
- `list_directory` — Read — https://policylayer.com/tools/filesystem/list-directory.md
- `list_directory_with_sizes` — Read — https://policylayer.com/tools/filesystem/list-directory-with-sizes.md
- `read_media_file` — Read — https://policylayer.com/tools/filesystem/read-media-file.md
- `read_multiple_files` — Read — https://policylayer.com/tools/filesystem/read-multiple-files.md
- `read_text_file` — Read — https://policylayer.com/tools/filesystem/read-text-file.md
- `search_files` — Read — https://policylayer.com/tools/filesystem/search-files.md
- `create_directory` — Write — https://policylayer.com/tools/filesystem/create-directory.md
- `edit_file` — Write — https://policylayer.com/tools/filesystem/edit-file.md
- `move_file` — Write — https://policylayer.com/tools/filesystem/move-file.md
- `write_file` — Write — https://policylayer.com/tools/filesystem/write-file.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=filesystem · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/filesystem