MCP/Server/Simple.pm

=head1 NAME

AnyEvent::MCP::Server::Simple - simple function interface for MCP servers

=head1 SYNOPSIS

   use AnyEvent::MCP::Server::Simple;

   mcp_config
      server_info   => {
         name    => "example",
         version => "0",
      },
      instructions => <<'EOF';
         Use echo to return the supplied text.
   EOF

   mcp_tool echo =>
      "Return the supplied text.",
      {
         type       => "object",
         properties => { text => { type => "string" } },
         required   => ["text"],
      },
      sub {
         my ($req, $args) = @_;

         $req->reply ({
            content => [{ type => "text", text => $args->{text} }],
         });
      };

   mcp_start;

=head1 DESCRIPTION

For most MCP servers, registering a few tools and starting a transport is
enough. This module does just that: call C<mcp_tool> to register callbacks,
optionally configure the server with C<mcp_config>, then start it with
C<mcp_start>, C<mcp_stdio> or C<mcp_http>. Registration alone does not start
a server or an event loop.

Human-readable descriptions and instructions are stripped of surrounding
whitespace and common indentation when registered, so indented here-documents
can be used naturally.

C<mcp_start>, C<mcp_stdio> and C<mcp_http> are alternative blocking entry
points for a self-contained server. They run AnyEvent until shutdown; you
do not start another event loop. If your application already owns the server
lifetime or needs several transports, use the object interfaces instead.

Simple uses L<AnyEvent::MCP::Server> and a default Toolset internally; it is
not a second server implementation. Applications needing custom dispatch,
such as a multibroker, can use the Server API directly.

=head1 FUNCTIONS

=over

=item mcp_config %config

Adds server configuration. Repeated calls extend or replace previously declared
values. C<instructions> is treated as human-readable text and normalized.

C<server_info> contains the MCP server metadata, including C<name> and
C<version>. C<instructions> contains guidance for the client.

C<on_request> is a synchronous hook called before dispatch:

   $callback->($server, $req)

For example, an application can refresh database state before each request.
It does not replace dispatch or receive a completion callback. These options
belong to Server; Simple merely collects and passes them on.

C<on_start> is C<$callback->($server)>, called after the transport is ready
and before entering the event loop. It can print application startup
information or install watchers. C<$server> is the underlying server object.
The callback must not block.

=item mcp_tool $name, $description, $input_schema, $callback->($req, $args)

Registers a tool named C<$name> with C<$description> and the JSON Schema
hash reference C<$input_schema>. C<$description> is normalized like
C<instructions>.

C<$callback> receives an L<AnyEvent::MCP::Server::Request> object C<$req>
and its C<< $req->{args} >> hash reference as C<$args>, for convenience.

Tools complete the request with C<< $req->reply ($result) >>, or use
C<< $req->result ($data) >> and C<< $req->error ($message) >> for convenience.
Request context is available directly in
the hash, for example C<< $req->{tool} >> and C<< $req->{server} >>.

=item mcp_start %config

Starts and runs the usual server. When
C<PERL_ANYEVENT_MCP_MULTIBROKER_PROTOCOL> is C<stdio>, uses C<mcp_stdio>.
Otherwise starts HTTP without printing its URL. HTTP-capable executables
provide C<--print-url> to retrieve the URL explicitly.

The HTTP defaults are IPv4 loopback, a stable name-derived port in
16384..32767, and C</> as the endpoint path.
The selected token authenticates either its URL path or an
C<Authorization: Bearer TOKEN> header at the clean URL returned by
C<< $server->url (0) >>. C<anyevent-mcp token NAME> prints this token.

C<name> selects the C<[server NAME]> configuration section and credential.
It defaults to the program's basename.
Named settings C<bind>, C<path>, C<url_host>, C<url_scheme> and C<tokens>
are loaded from the global configuration. Repeated C<--token> options
replace the configured list in the executables.
An explicit C<bind> overrides the configured bind address. Other arguments
override these settings. Explicit authentication options replace the default authentication.

The global secret is generated automatically when needed; see
L<AnyEvent::MCP/GLOBAL CONFIGURATION>. No configuration is loaded for stdio.
HTTP startup neither prints to stdout nor changes its buffering.

=item mcp_stdio %config

Creates and runs a server over stdin/stdout. Arguments override the collected
configuration. Stdout buffering is disabled. On stdin EOF, pending replies
finish and stdout drains before
this function returns. Stream errors close the connection and cancel pending
requests.

=item mcp_http %config

Creates and runs an HTTP server. For example:

   mcp_http
      host => "127.0.0.1",
      port => 31740,
      path => "/mcp/";

Arguments override the collected configuration. Unlike C<mcp_start>, this
function does not supply cookie authentication or print a URL; use
C<on_start> for application-specific startup output.

All three starters return when the server is closed or on C<SIGINT> or
C<SIGTERM>. Signal shutdown closes connections and cancels outstanding
requests. The signal watchers belong to the blocking call.

=back

=cut

package AnyEvent::MCP::Server::Simple;

use common::sense;
use AnyEvent ();
use AnyEvent::MCP ();
use AnyEvent::MCP::Server::Toolset ();
use Exporter ();

our @ISA = qw(Exporter);
our @EXPORT = qw(mcp_config mcp_tool mcp_start mcp_stdio mcp_http);

my %config;
my $toolset = AnyEvent::MCP::Server::Toolset->new;

sub _run;

sub mcp_config {
   my %kv = @_;

   $kv{instructions} = AnyEvent::MCP::_clean_text $kv{instructions}
      if exists $kv{instructions};

   @config{keys %kv} = values %kv;
}

sub mcp_tool {
   $toolset->tool (@_)
}

sub mcp_start {
   require AnyEvent::MCP::Config;

   my %kv = (%config, @_);
   my $name = AnyEvent::MCP::Config::server_name ($kv{name});

   $kv{name} = $name;
   $kv{server_info} ||= { name => $name, version => "0" };

   return mcp_stdio (%kv)
      if $ENV{PERL_ANYEVENT_MCP_MULTIBROKER_PROTOCOL} eq "stdio";

   my $global = AnyEvent::MCP::Config->global;

   %kv = (
      path => "/",
      $global->http_settings ($name, delete $kv{bind}),
      %kv,
   );

   mcp_http (%kv)
}

sub mcp_stdio {
   require AnyEvent::MCP::Server::JSONL;

   binmode STDIN;
   binmode STDOUT;
   my $selected = select STDOUT;
   $| = 1;
   select $selected;

   my $server = AnyEvent::MCP::Server::JSONL->new (toolsets => [$toolset], %config, @_);
   $server->accept (\*STDIN, \*STDOUT);
   _run $server
}

sub mcp_http {
   require AnyEvent::MCP::Server::HTTP;

   my $server = AnyEvent::MCP::Server::HTTP->new (toolsets => [$toolset], %config, @_);
   $server->listen;
   _run $server
}

sub _run {
   my ($server) = @_;

   my $cv = AnyEvent->condvar;
   my $stopped;
   my $stop = sub { $cv->send unless $stopped++ };
   my $on_close = $server->{on_close};
   $server->{on_close} = sub {
      $on_close->(@_) if $on_close;
      $stop->();
   };

   if ($server->isa ("AnyEvent::MCP::Server::JSONL")) {
      my $on_connection_close = $server->{on_connection_close};
      $server->{on_connection_close} = sub {
         $on_connection_close->(@_) if $on_connection_close;
         $stop->();
      };
   }

   my @signals = map {
      AnyEvent->signal (signal => $_, cb => sub { $server->close })
   } qw(INT TERM);

   my $ok = eval {
      $server->event (start =>);
      $cv->recv;
      1
   };
   my $error = $@;
   $server->close;
   die $error unless $ok;
   return
}

1
Revision:	1.5
Committed:	Sun Oct 11 00:53:55 2026 UTC (4 weeks, 2 days ago) by root
Branch:	MAIN
Changes since 1.4:	+5 -4 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			AnyEvent::MCP::Server::Simple - simple function interface for MCP servers
4
5			=head1 SYNOPSIS
6
7			use AnyEvent::MCP::Server::Simple;
8
9			mcp_config
10			server_info => {
11			name => "example",
12			version => "0",
13			},
14			instructions => <<'EOF';
15			Use echo to return the supplied text.
16			EOF
17
18			mcp_tool echo =>
19			"Return the supplied text.",
20			{
21			type => "object",
22			properties => { text => { type => "string" } },
23			required => ["text"],
24			},
25			sub {
26			my ($req, $args) = @_;
27
28			$req->reply ({
29			content => [{ type => "text", text => $args->{text} }],
30			});
31			};
32
33			mcp_start;
34
35			=head1 DESCRIPTION
36
37	root	1.2	For most MCP servers, registering a few tools and starting a transport is
38			enough. This module does just that: call C<mcp_tool> to register callbacks,
39			optionally configure the server with C<mcp_config>, then start it with
40			C<mcp_start>, C<mcp_stdio> or C<mcp_http>. Registration alone does not start
41			a server or an event loop.
42	root	1.1
43			Human-readable descriptions and instructions are stripped of surrounding
44			whitespace and common indentation when registered, so indented here-documents
45			can be used naturally.
46
47			C<mcp_start>, C<mcp_stdio> and C<mcp_http> are alternative blocking entry
48	root	1.2	points for a self-contained server. They run AnyEvent until shutdown; you
49			do not start another event loop. If your application already owns the server
50			lifetime or needs several transports, use the object interfaces instead.
51
52			Simple uses L<AnyEvent::MCP::Server> and a default Toolset internally; it is
53			not a second server implementation. Applications needing custom dispatch,
54			such as a multibroker, can use the Server API directly.
55	root	1.1
56			=head1 FUNCTIONS
57
58			=over
59
60			=item mcp_config %config
61
62			Adds server configuration. Repeated calls extend or replace previously declared
63			values. C<instructions> is treated as human-readable text and normalized.
64
65			C<server_info> contains the MCP server metadata, including C<name> and
66			C<version>. C<instructions> contains guidance for the client.
67
68			C<on_request> is a synchronous hook called before dispatch:
69
70			$callback->($server, $req)
71
72			For example, an application can refresh database state before each request.
73			It does not replace dispatch or receive a completion callback. These options
74			belong to Server; Simple merely collects and passes them on.
75
76			C<on_start> is C<$callback->($server)>, called after the transport is ready
77			and before entering the event loop. It can print application startup
78			information or install watchers. C<$server> is the underlying server object.
79			The callback must not block.
80
81			=item mcp_tool $name, $description, $input_schema, $callback->($req, $args)
82
83			Registers a tool named C<$name> with C<$description> and the JSON Schema
84			hash reference C<$input_schema>. C<$description> is normalized like
85			C<instructions>.
86
87			C<$callback> receives an L<AnyEvent::MCP::Server::Request> object C<$req>
88			and its C<< $req->{args} >> hash reference as C<$args>, for convenience.
89
90			Tools complete the request with C<< $req->reply ($result) >>, or use
91			C<< $req->result ($data) >> and C<< $req->error ($message) >> for convenience.
92			Request context is available directly in
93			the hash, for example C<< $req->{tool} >> and C<< $req->{server} >>.
94
95			=item mcp_start %config
96
97			Starts and runs the usual server. When
98			C<PERL_ANYEVENT_MCP_MULTIBROKER_PROTOCOL> is C<stdio>, uses C<mcp_stdio>.
99	root	1.4	Otherwise starts HTTP without printing its URL. HTTP-capable executables
100			provide C<--print-url> to retrieve the URL explicitly.
101	root	1.1
102	root	1.3	The HTTP defaults are IPv4 loopback, a stable name-derived port in
103			16384..32767, and C</> as the endpoint path.
104	root	1.5	The selected token authenticates either its URL path or an
105			C<Authorization: Bearer TOKEN> header at the clean URL returned by
106	root	1.1	C<< $server->url (0) >>. C<anyevent-mcp token NAME> prints this token.
107
108			C<name> selects the C<[server NAME]> configuration section and credential.
109	root	1.3	It defaults to the program's basename.
110	root	1.5	Named settings C<bind>, C<path>, C<url_host>, C<url_scheme> and C<tokens>
111			are loaded from the global configuration. Repeated C<--token> options
112			replace the configured list in the executables.
113	root	1.3	An explicit C<bind> overrides the configured bind address. Other arguments
114	root	1.1	override these settings. Explicit authentication options replace the default authentication.
115
116			The global secret is generated automatically when needed; see
117			L<AnyEvent::MCP/GLOBAL CONFIGURATION>. No configuration is loaded for stdio.
118	root	1.4	HTTP startup neither prints to stdout nor changes its buffering.
119	root	1.1
120			=item mcp_stdio %config
121
122			Creates and runs a server over stdin/stdout. Arguments override the collected
123			configuration. Stdout buffering is disabled. On stdin EOF, pending replies
124			finish and stdout drains before
125			this function returns. Stream errors close the connection and cancel pending
126			requests.
127
128			=item mcp_http %config
129
130			Creates and runs an HTTP server. For example:
131
132			mcp_http
133			host => "127.0.0.1",
134			port => 31740,
135			path => "/mcp/";
136
137			Arguments override the collected configuration. Unlike C<mcp_start>, this
138			function does not supply cookie authentication or print a URL; use
139			C<on_start> for application-specific startup output.
140
141			All three starters return when the server is closed or on C<SIGINT> or
142			C<SIGTERM>. Signal shutdown closes connections and cancels outstanding
143			requests. The signal watchers belong to the blocking call.
144
145			=back
146
147			=cut
148
149			package AnyEvent::MCP::Server::Simple;
150
151			use common::sense;
152			use AnyEvent ();
153			use AnyEvent::MCP ();
154			use AnyEvent::MCP::Server::Toolset ();
155			use Exporter ();
156
157			our @ISA = qw(Exporter);
158			our @EXPORT = qw(mcp_config mcp_tool mcp_start mcp_stdio mcp_http);
159
160			my %config;
161			my $toolset = AnyEvent::MCP::Server::Toolset->new;
162
163			sub _run;
164
165			sub mcp_config {
166			my %kv = @_;
167
168			$kv{instructions} = AnyEvent::MCP::_clean_text $kv{instructions}
169			if exists $kv{instructions};
170
171			@config{keys %kv} = values %kv;
172			}
173
174			sub mcp_tool {
175			$toolset->tool (@_)
176			}
177
178			sub mcp_start {
179	root	1.3	require AnyEvent::MCP::Config;
180	root	1.1
181			my %kv = (%config, @_);
182	root	1.3	my $name = AnyEvent::MCP::Config::server_name ($kv{name});
183	root	1.1
184			$kv{name} = $name;
185			$kv{server_info} \|\|= { name => $name, version => "0" };
186
187			return mcp_stdio (%kv)
188			if $ENV{PERL_ANYEVENT_MCP_MULTIBROKER_PROTOCOL} eq "stdio";
189
190			my $global = AnyEvent::MCP::Config->global;
191
192			%kv = (
193			path => "/",
194	root	1.3	$global->http_settings ($name, delete $kv{bind}),
195	root	1.1	%kv,
196			);
197
198	root	1.4	mcp_http (%kv)
199	root	1.1	}
200
201			sub mcp_stdio {
202			require AnyEvent::MCP::Server::JSONL;
203
204			binmode STDIN;
205			binmode STDOUT;
206			my $selected = select STDOUT;
207			$\| = 1;
208			select $selected;
209
210			my $server = AnyEvent::MCP::Server::JSONL->new (toolsets => [$toolset], %config, @_);
211			$server->accept (\STDIN, \STDOUT);
212			_run $server
213			}
214
215			sub mcp_http {
216			require AnyEvent::MCP::Server::HTTP;
217
218			my $server = AnyEvent::MCP::Server::HTTP->new (toolsets => [$toolset], %config, @_);
219			$server->listen;
220			_run $server
221			}
222
223			sub _run {
224			my ($server) = @_;
225
226			my $cv = AnyEvent->condvar;
227			my $stopped;
228			my $stop = sub { $cv->send unless $stopped++ };
229			my $on_close = $server->{on_close};
230			$server->{on_close} = sub {
231			$on_close->(@_) if $on_close;
232			$stop->();
233			};
234
235			if ($server->isa ("AnyEvent::MCP::Server::JSONL")) {
236			my $on_connection_close = $server->{on_connection_close};
237			$server->{on_connection_close} = sub {
238			$on_connection_close->(@_) if $on_connection_close;
239			$stop->();
240			};
241			}
242
243			my @signals = map {
244			AnyEvent->signal (signal => $_, cb => sub { $server->close })
245			} qw(INT TERM);
246
247			my $ok = eval {
248			$server->event (start =>);
249			$cv->recv;
250			1
251			};
252			my $error = $@;
253			$server->close;
254			die $error unless $ok;
255			return
256			}
257
258			1