MCP servers

The MCP servers lens records every call to the MCP servers your application provides with laravel/mcp: which method was called, which tool, resource or prompt, the arguments, how long it took and whether it failed. Over HTTP a call is part of the request capture; over stdio each call becomes a capture of its own, of type mcp.

Rows

Section mcp

Over HTTP, mcp has one row per call on the request capture. Over stdio, the capture is the call, and mcp holds the same fields once, as facts rather than rows. The capture is named {server}: {method} {primitive}, such as weather: tools/call forecast, and its status is ok or error.

Recorded methods are tools/call, resources/read, prompts/get, tools/list, resources/list, resources/templates/list, prompts/list, completion/complete, initialize, ping and the server's discovery method.

Field	Meaning	Unit	Missing when
server	The server's name.	-	never
method	The JSON-RPC method, such as tools/call.	-	never
primitive	The tool or prompt name, or the resource URI.	-	the method is not about one tool, prompt or resource, such as tools/list
arguments	The arguments sent to a tool or prompt.	-	the call had none
protocol_version	The protocol version the client asked for.	-	only set on initialize
duration	How long the server took to answer. For a streamed answer, until the last chunk was sent.	ms	never
is_error	true when the answer was a JSON-RPC error, a tool result marked as an error, a streamed answer with any error chunk, or the handler threw.	-	never (false)
streamed_chunks	How many chunks a streamed answer sent.	count	never (0 for an answer that was not streamed)
exception	The exception the handler threw.	-	the handler did not throw
time	When the call started, counted from the start of the capture.	ms	stdio captures

Rows in mcp have no origin.

In the timeline

Each call is an mcp span named after the method and primitive, such as tools/call forecast, with its server, method, primitive, arguments, protocol version, is_error and chunks. Spans started while the call ran sit under it.

Totals, warnings and errors

The summary gets these totals when the capture has at least one call:

Total	Label	Value
mcp_ms	spent	The duration of every call added up, in ms.
mcp_calls	calls	The number of calls.
mcp_errors	errors	The number of calls with is_error set.

This lens reports no warnings. It reports one error per call with is_error set, for the first three such calls:

• MCP {method} {primitive} returned an error.

A stdio call that ended in an error also gives its capture the status error. See Warnings and errors for how errors are shown.

In the dashboard

On a request capture, the MCP tab lists the calls in the order they happened. The columns are the fields that have a value in some row, up to eight, with duration last. There are no grouping chips. Click a row to fold it out to every field, including the arguments and the exception.

On a capture of type mcp, the MCP tab shows the call's fields as a list. In the capture list, these captures have the type mcp.

For agents

List the stdio calls to your servers from the last 15 minutes:

{
  "tool": "monocle-list",
  "arguments": {"type": "mcp", "since": "15m"}
}

Show one stdio call with what it did, using an id from the list:

{
  "tool": "monocle-show",
  "arguments": {"id": "<capture id>", "sections": ["summary", "mcp", "timeline"]}
}

On a request capture made over HTTP, list the calls that failed:

{
  "tool": "monocle-rows",
  "arguments": {
    "section": "mcp",
    "where": [{"field": "is_error", "op": "=", "value": "true"}],
    "fields": ["server", "method", "primitive", "arguments", "exception.message", "duration"]
  }
}

See For AI agents for every argument.

Configuration

Turn the lens on or off under lenses in config/monocle.php, keyed by McpLens::class: true runs it, false turns it off. See Lenses. The lens has no options of its own.

Other settings that affect this lens:

• mcp.except_servers - servers whose calls are never recorded, matched by name in any letter case. Default ['monocle', 'laravel-boost'], so calls to Monocle's own server and to Laravel Boost are left out. Setting it replaces the default.
• except - calls over HTTP to a path in except.paths are not recorded, since the request is not.
• dashboard.tabs - where the MCP tab sits among the tabs.
• Masking - argument keys matching mask.inputs are masked, also inside nested arguments. Entries keyed by McpLens::class apply to this lens only.

use ExeQue\Monocle\Lenses\Packages\Laravel\McpLens;

'lenses' => [
    // ...
    McpLens::class => true,
],

'mcp' => [
    'enabled' => true,
    'server' => 'monocle',
    'except_servers' => ['monocle', 'laravel-boost', 'internal-tools'],
],

Requirements and limits

• Needs laravel/mcp. Without it the lens does nothing.
• Records the servers your application provides, not MCP servers your application calls as a client.
• Arguments are masked by key only. A secret under a key that does not match mask.inputs is stored as it is.
• The answer a call returned is not stored; only whether it was an error and how many chunks it streamed.