entropic::BashServer Class Reference

Bash MCP server for shell command execution. More...

#include <entropic/mcp/servers/bash.h>

Inheritance diagram for entropic::BashServer:

Collaboration diagram for entropic::BashServer:

Public Member Functions
	BashServer (const std::filesystem::path &working_dir, const std::string &data_dir, int timeout=30)
	Construct with working directory and data dir.
	~BashServer () override
	Destructor.
std::string	get_permission_pattern (const std::string &tool_name, const std::string &args_json) const override
	Permission pattern: "execute:{base_cmd} *".
bool	set_working_dir (const std::string &path) override
	Set working directory.
const std::filesystem::path &	working_dir () const
	Get the working directory.
int	timeout () const
	Get the enforced per-command timeout.
Public Member Functions inherited from entropic::MCPServerBase
	MCPServerBase (std::string name)
	Construct with server name.
const std::string &	name () const
	Get the server name.
void	register_tool (ToolBase *tool)
	Register a tool with this server.
std::string	list_tools () const
	List all registered tools as a JSON array string.
std::string	execute (const std::string &tool_name, const std::string &raw_args_json)
	Execute a tool and wrap result in ServerResponse JSON.
virtual bool	skip_duplicate_check (const std::string &tool_name) const
	Check if a tool should skip duplicate detection.
virtual bool	configure (const std::string &config_json)
	Configure the server after creation.
const ToolRegistry &	registry () const
	Get the tool registry (const).

Additional Inherited Members
Protected Attributes inherited from entropic::MCPServerBase
std::string	name_
	Server name.
ToolRegistry	registry_
	Tool registry.

Detailed Description

Bash MCP server for shell command execution.

Single tool: execute. Runs /bin/sh -c in the server's working directory as the leader of its OWN process group, captures stdout and stderr together, and enforces timeout() on the wall clock: on expiry the whole group is SIGKILLed (background children included), the shell is reaped, and the model gets a typed timeout error naming the limit and the elapsed time, with whatever the command printed so far. When the command finishes normally, anything it left running in its group is killed too — a tool call does not leave processes behind. (A command that deliberately leaves its group, e.g. via setsid, escapes this.)

What it does NOT do

It does not filter commands. Nothing here inspects the command text: whether a command runs at all is decided before execute() is reached, by the permission layer (permissions.allow / permissions.deny patterns, keyed by get_permission_pattern()) and the tool-approval gate. Until v2.13.0 this comment claimed the server "blocks dangerous commands" and "enforces timeout"; neither was true — there was never a denylist, and the timeout was stored and never read.

Version

2.13.0

Definition at line 44 of file bash.h.

Constructor & Destructor Documentation

BashServer()

entropic::BashServer::BashServer	(	const std::filesystem::path &	working_dir,
		const std::string &	data_dir,
		int	timeout = 30
	)

Construct with working directory and data dir.

Parameters

working_dir	Default working directory for commands.
data_dir	Path to bundled data directory.
timeout	Per-command wall-clock limit in seconds (enforced since v2.13.0; mcp.bash.timeout_seconds, default 30).

Version

2.13.0

A thin MCPServerBase subclass: it builds its one tool, registers it, and overrides only get_permission_pattern and set_working_dir.

Parameters

working_dir	Default working directory for commands.
data_dir	Path to bundled data directory.
timeout	Command timeout in seconds. @req REQ-MCP-001 @req REQ-MCP-023

Version

1.8.5

Definition at line 528 of file bash.cpp.

~BashServer()

entropic::BashServer::~BashServer ( )

overridedefault

Destructor.

@dg_internal

Version

1.8.5

Member Function Documentation

get_permission_pattern()

std::string entropic::BashServer::get_permission_pattern ( const std::string &  tool_name, const std::string &  args_json  ) const

overridevirtual

Permission pattern: "execute:{base_cmd} *".

Parameters

tool_name	Tool name.
args_json	Arguments JSON.

Returns

Permission pattern with base command.

Version

1.8.5

Approval granularity matters here: keying on the base command means an operator's "always allow" applies to a command family rather than to every shell invocation.

Parameters

tool_name	Tool name.
args_json	Arguments JSON.

Returns

"<tool>:<base command> *" — for python -m x, the pattern names python. Unparseable arguments degrade to a base command of "unknown" (logged), never a wildcard. @req REQ-MCP-023 @req REQ-MCP-009

Version

1.8.5

Reimplemented from entropic::MCPServerBase.

Definition at line 572 of file bash.cpp.

set_working_dir()

bool entropic::BashServer::set_working_dir ( const std::string &  path )

overridevirtual

Set working directory.

Set the working directory.

Parameters

path	New working directory.

Returns

true on success.

Version

1.8.5

Re-targets the server so a sandbox swap does not require reconstructing it.

Parameters

path	New working directory.

Returns

true — the re-target always succeeds; the path itself is validated per call by is_safe_cwd. @req REQ-MCP-023

Version

1.8.5

Reimplemented from entropic::MCPServerBase.

Definition at line 600 of file bash.cpp.

timeout()

int entropic::BashServer::timeout

(

)

const

Get the enforced per-command timeout.

Get command timeout.

Returns

Timeout in seconds.

Version

2.13.0

Returns

The enforced per-command timeout in seconds. @req REQ-MCP-023

Version

1.8.5

Definition at line 623 of file bash.cpp.

working_dir()

const std::filesystem::path & entropic::BashServer::working_dir

(

)

const

Get the working directory.

Returns

Working directory path.

Version

1.8.5

Returns

The directory commands default to when a call omits working_dir. @req REQ-MCP-023

Version

1.8.5

Definition at line 613 of file bash.cpp.

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The documentation for this class was generated from the following files:

• entropic/mcp/servers/bash.h
• mcp/servers/bash.cpp