webx-ui/mcp

webx-ui/mcp

How a WebX UI admin module offers itself to an AI agent, and the server that serves what they offer.

Every module declares the tools, resources and prompts it has; this package collects them from the installed modules and serves the lot as one MCP server over Streamable HTTP and over stdio. A panel therefore exposes exactly the tools of the modules it actually has.

Requirements

• PHP 8.4+
• Laravel 13
• webx-ui/module-admin; laravel/mcp comes with this package

Install

composer require webx-ui/mcp
php artisan webx:mcp-tools

The server answers at {api_path}/mcp — /api/cms/mcp by default — as soon as the package is installed, and it is closed: without a token it answers 401 and says where to get one.

A local agent on the machine the site runs on needs none: php artisan mcp:start webx is the same server over stdio, trusted the way tinker is trusted.

Letting a person connect their agent

Anyone else connects over OAuth. Passport does the issuing; it comes with webx-ui/module-auth, and a site switches it on once:

php artisan vendor:publish --tag=passport-migrations && php artisan migrate
php artisan passport:keys

Without the keys the guard cannot be built at all, and a call with no token answers 500 where it should answer 401 — so this is a deployment step, not an optional one.

From then on the address is all a person needs, and it carries nothing secret:

https://example.com/api/cms/mcp

Pasted into Claude, ChatGPT or claude mcp add --transport http webx <address>, the client discovers the authorization server from the 401, registers itself, and sends the person to the panel to sign in and agree. What it leaves with is a token of theirs — so the agent acts as that administrator, and switching the account off ends its access the same minute.

Two things ship open and this package closes them: config('mcp.redirect_domains') is ['*'] by default, which would let anybody register a client that takes the code to their own server, and client registration has no rate limit. Both are in webx-mcp.oauth, and a client whose redirect address is not on the list cannot connect until it is added.

Keys for machines — CI, scripts, anything with no browser to open — are not here yet. The console command that used to print one went with Sanctum.

Declaring tools

use WebxUi\Admin\AbstractModule;
use WebxUi\Mcp\Contracts\ProvidesMcpTools;
use WebxUi\Mcp\ProvidesMcpDefaults;
use WebxUi\Mcp\Tool;

class SeoModule extends AbstractModule implements ProvidesMcpTools
{
    use ProvidesMcpDefaults; // nothing to say about resources or prompts yet

    public function id(): string
    {
        return 'seo';
    }

    public function mcpTools(): array
    {
        return [
            Tool::read(
                'get',
                'Read the SEO fields of one entity.',
                fn (array $arguments) => $this->seo->for($arguments['id']),
                [
                    'properties' => ['id' => ['type' => 'string']],
                    'required' => ['id'],
                ],
            ),

            Tool::mutating(
                'bulk_update',
                'Apply a title template to every entity matching a filter.',
                fn (array $arguments, ?Authenticatable $user) => $this->seo->applyTemplate($arguments, by: $user),
                ['properties' => ['template' => ['type' => 'string']]],
            ),
        ];
    }
}

CRUD is the floor, not the goal. The tools worth writing are the ones that answer a question a person would otherwise answer by clicking for an hour: bulk edits, audits of what is missing or duplicated, "what changed this week", drafts for a human to approve.

A handler gets the arguments as the agent sent them and the administrator the call acts as — null on the stdio server, where there is no request. What it returns is what the agent reads: a map goes out as structured content with its JSON as text, a string as it is. A refusal the agent should read — "no such block", "the template failed on line 12" — is a thrown WebxUi\Mcp\Exceptions\ToolFailure; any other exception is reported and, outside debug mode, reaches the agent as "something went wrong".

Why two constructors instead of one

Tool::mutating() is not a flag on Tool::read() — the difference is the whole safety story.

A mutating tool is given a dry_run argument whether its author remembered one or not, so any change can be asked about before it happens. It also gets <module>:write as its scope, where a read tool gets <module>:read, which is what a token is checked against — before the handler runs, so no handler has to ask who is calling.

$tool->isDryRun($arguments); // the handler decides what to do about it

The same split names the panel permission the tool is behind: a mutating tool needs <module>.manage, a read tool <module>.view — or <module>.manage, because somebody who may edit may look, the way the module's own routes let them. A module whose permissions are not named after its id says so on the tool, with one name or several that mean "any of these":

Tool::read('list', '…', $handler, permission: ['blog.articles.view', 'blog.taxonomy.manage']);
Tool::mutating('merge', '…', $handler, permission: 'blog.taxonomy.manage');

Both are checked in the same place as the scope, before the handler; and tools/list leaves out what the caller may not use, so an agent is never shown a tool only to be refused it.

A tool without a description is refused, and so is a name a model could not call — the name goes to the agent verbatim, so it must be lowercase letters, digits and underscores.

Reading the registry

use WebxUi\Mcp\Registry\ToolRegistry;

$registry->tools();              // every tool, as BoundTool
$registry->toolsOf('seo');       // one module's
$registry->tool('seo_get');      // by the name an agent uses
$registry->scopes();             // ['media:audit', 'seo:read', 'seo:write']

A tool's public name is <module>_<tool>, with dashes in the module id turned into underscores — so a module names its tools short (get, not get_seo). Two modules cannot end up with the same one; the registry refuses rather than letting one shadow the other.

php artisan webx:mcp-tools --module=seo

The server

WebxUi\Mcp\Server\WebxServer is a laravel/mcp server that declares nothing of its own: when it starts it reads the registry and wraps every tool, resource and prompt in the class the transport expects. The module's JSON Schema goes out as written; a read tool is announced with readOnlyHint, so a client may skip its confirmation for it.

tools/list answers with a hundred at a time rather than the default fifteen. A panel with six modules offers more than forty tools, and a client that does not follow the cursor would see a third of them and conclude the rest do not exist.

config/webx-mcp.php:

webx.mcp-auth answers 401 as JSON without a user, 403 for an administrator switched off since the token was issued, and makes the guard the default so that $request->user() in a tool is this administrator. Any other middleware goes in its place.

The api guard is registered for you — Passport's driver over webx-auth.provider, the panel's own people — unless the application has already defined one under that name.

webx-mcp.oauth has guard (whom Passport asks at the consent screen: the panel's people, not the site's visitors), redirect_domains and custom_schemes (what config/mcp.php is set to), register_throttle, and how long a token and its refresh last — an hour and a month.

A scope is what the token carries. A token issued over OAuth carries one for the whole server, mcp:use, because that is the only scope a client is ever offered there: it says an agent may talk to the panel and nothing about which module, and what limits the call is the administrator's own permissions. A token that names module scopes is read scope by scope. A caller without a token at all — the stdio server, or a person signed in through a session — is not asked for one: the middleware that let them in decides.

The permissions are the administrator's own, as the panel checks them (HasPermissions from webx-ui/module-admin): an agent let in by an editor can do what that editor can do, and its tools/list is already that — a narrower role sees a shorter list. On the stdio server there is nobody to ask, so everything is listed. "Read only" on the consent screen sits above both: it refuses every tool that writes, whatever the person may do themselves.

The call log

Every tool call lands in mcp_calls: who the agent acted as (cms_user_id), on which connection (grant_id), which tool, the arguments, whether it was a dry run, whether it was answered or refused and with what words, and how long it took. It is written in one place, around the whole of the call — so a refusal at the door for a scope, a read-only connection or a missing permission is a row, and so is what the handler threw. A handler that answers ['ok' => false, 'reason' => …] is written down as refused too: that is what the person reading the log would call it.

No secret reaches it. The token and the headers are never looked at, and any argument named like one — password, token, api_key, secret, authorization — is blanked before writing. Arguments are cut to calls.arguments_length characters. There is deliberately no link from a call to a page or a file: tools are about different things, and a log that pretended otherwise would be wrong more often than useful.

webx:mcp:prune-calls removes rows older than calls.days and runs nightly on the scheduler; null keeps them forever, calls.enabled false writes nothing. webx-ui/module-auth shows the log in the panel, next to the administrators, behind admins.audit.

What is not here yet

A queue of changes awaiting approval in the panel, a screen for the connections, and keys for machines — CI and scripts, which have no browser to send anybody to.

Licence

MIT.