Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@basic-fns-mcp grep for TODO in the project"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
A streamable-HTTP/stdio MCP server exposing the core filesystem, shell, search, and listing tools that mirror the default agent toolset.
Tool | Hint | Purpose |
| readOnly | Read a text file with cat-style line numbers |
| destructive | Create or overwrite a file atomically |
| destructive | Create a directory and any missing parents |
| destructive | Targeted string replacement in a text file |
| destructive | Execute a shell command and capture output/exit code |
| readOnly | Search file contents by regex (uses |
| readOnly | Find files/directories by glob-style name match |
| readOnly | List directory contents |
All filesystem paths are resolved relative to the configured server root. The server refuses any path that resolves outside that root, including symlinks that escape it.
Related MCP server: MCP File Server
Install and run over HTTP:
uv sync
uv run basic-fns-mcp --root . --port 8080Add it to Claude Code:
claude mcp add --transport http basic-fns http://127.0.0.1:8080/mcpThe same server runs over stdio, where the client spawns it as a subprocess:
uv run basic-fns-mcp --stdio # or: --transport stdioAdd it to Claude Code:
claude mcp add basic-fns -- uv run --directory /path/to/basic-fns-mcp basic-fns-mcp --stdioOr in an MCP client config file:
{
"mcpServers": {
"basic-fns": {
"command": "uv",
"args": ["run", "--directory", "/path/to/basic-fns-mcp", "basic-fns-mcp", "--stdio"],
"env": { "BASIC_FNS_ROOT": "/path/to/your/project" }
}
}
}On stdio, stdout is the protocol channel — the startup banner is suppressed and all
logging goes to stderr. The --host/--port flags are ignored.
The module can also be served directly, since tools are registered at import time:
uv run fastmcp run src/basic_fns_mcp/server.pyFlag | Environment variable | Default | Meaning |
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| current working directory | Sandbox root; all paths resolve under it |
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| HTTP bind address |
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| HTTP bind port |
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| Refuse |
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| Cap any tool result to this length |
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| Default shell timeout in seconds |
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| Disable |
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| Do not register the |
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Command-line arguments win over environment variables.
Path sandbox: read, write, mkdir, edit, grep, find, and ls resolve every path inside --root. Symlinks are followed and checked; any path that resolves outside the root is rejected.
bash is not sandboxed: bash runs with the full privileges of the server process. A shell command can cd anywhere, read any file the server user can read, and execute arbitrary code. Only bind to loopback (127.0.0.1) and expose this server to trusted clients.
No command blocklist: Blocklists are easily bypassed and create a false sense of security, so none is implemented.
Read-only mode: Use --read-only to prevent file modification via this server.
Run the test suite:
uv run pytest -qMIT
Execute a shell command and return exit code, stdout, and stderr.
Inputs: command (required), cwd, timeout. Returns: result
Replace old_string with new_string in a text file.
Inputs: path (required), new_string (required), old_string (required), replace_all. Returns: result
Find files or directories by glob-style name match.
Inputs: path, type, pattern, max_results. Returns: result
Search file contents by regex.
Inputs: pattern (required), glob, path, max_results, +1 more. Returns: result
List the contents of a directory.
Inputs: all, path. Returns: result
Read a text file and return its contents with cat-style line numbers.
Inputs: path (required), limit, offset. Returns: result
Create or overwrite a file atomically (temp file + os.replace).
Inputs: path (required), content (required). Returns: result
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
Loading tool schema changelog…
Scored across 7 tools
read, grep, find, and ls each target a distinct operation (reading content, searching content, finding files by name, listing directories), but the generic bash tool can perform all of these actions, creating overlap and ambiguity about when to use the specialized tools versus bash.
All tool names are single lowercase verbs (read, grep, find, ls, write, edit, bash) following a consistent Unix-command style. The naming pattern is uniform and predictable.
With 7 tools, the server is well-scoped for a basic file operations server. Each tool addresses a core operation (read, write, edit, search, list), and the count is within the ideal range.
The server covers create (write), read (read), and update (edit) but lacks an explicit delete, move, or copy operation. The bash tool can work around these gaps, but the dedicated surface is incomplete for full file lifecycle management.
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