> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hasmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Monitoring & Logs

> How to use real-time logs to debug connections, inspect payloads, and monitor LLM tool usage

## Realtime LLM Interaction Logs

Observability is crucial when building LLM agents. Because the model's decision-making process ("Which tool should I call?") is probabilistic, you need visibility into exactly what is happening under the hood.

HasMCP provides a real-time log stream for every MCP Server you create. This allows you to see:

* **Connection Events**: When a client (like Claude) connects or disconnects.
* **Tool Calls**: The exact arguments the LLM generated.
* **API Responses**: The raw data returned by your external provider.
* **Errors**: Authentication failures or schema validation issues.

## Accessing Logs

1. Navigate to the **MCP Servers** tab.
2. Locate the server you want to monitor.
3. Click the **Logs** icon (a document/file icon) in the top-right corner of the server card, or click "View MCP Server Logs" inside the server details page.

> **Status Indicator**: The top of the log window shows the connection status.
>
> * **Connecting...**: Establishing the Server-Sent Events (SSE) stream.
> * **Streaming...**: Live and receiving data.
> * **Disconnected**: The connection was lost or the tab was closed.

## Understanding Log Entries

The log viewer displays events in chronological order (newest at the top).

### 1. Connection Lifecycle

When you start your LLM client (e.g., open Claude Desktop), you should see an initialization sequence:

* `connection: init` - The client has established an HTTP connection.
* `capabilities: negotiation` - The client and server are agreeing on supported features (e.g., resources, tools).

### 2. Request / Response Cycle (The "Thinking" Process)

This is the most critical part for debugging. A typical tool use sequence looks like this:

**A. The Request (Blue)** The LLM decides to call a tool. You will see an event starting with `req`.

* **Event**: `req:call_tool`
* **Data**: `{"name": "list_customers", "arguments": {"limit": 5}}`
* *What to look for*: Did the model hallucinate an argument? Is the data type correct (e.g., string vs integer)?

**B. The Response (Green)** Your HasMCP server executes the request against the external API and returns the result.

* **Event**: `res:call_tool`
* **Data**: `{"content": [{"type": "text", "text": "..."}]}`
* *What to look for*: Did the API return the expected data? Is the JSON too large for the context window?

### 3. Errors (Red)

If something goes wrong, you will see a red error entry.

* **401 Unauthorized**: Usually means your [Environment Variable](/essentials/variables) is missing or incorrect.
* **404 Not Found**: The endpoint path might be configured incorrectly in the Provider settings.
* **500 Internal Error**: A parsing error or unexpected failure in the backend.

## Inspecting Payloads

LLM tool calls and API responses can be large JSON objects. HasMCP truncates these in the main view to keep the log readable.

**To view the full payload:**

1. Click directly on the `Data: {...}` text of any log entry.
2. A modal will open showing the **Prettified JSON**.
3. Use the **Copy JSON** button to paste it into an external editor or validator.

## Troubleshooting Common Scenarios

### "I don't see any logs when I use Claude."

* **Cause**: Claude Desktop might not be running or the configuration file points to the wrong URL.
* **Fix**: Restart Claude Desktop. Ensure the `mcpServers` config in your `claude_desktop_config.json` matches the snippet provided in the Server Details page.

### "The model keeps getting 'Invalid Arguments' errors."

* **Cause**: The JSON Schema defined in your Provider Endpoint might not match what the API actually expects.
* **Fix**: Go to the **Providers** tab, edit the endpoint, and check the **Query Arguments** or **Request Body** schema. Ensure `required` fields are actually marked as required.

### "I see a 401 error in the logs, but I added the variable."

* **Cause**: The variable name might not match the **Secret Prefix** required by the provider.
* **Fix**: Go to the **Variables** page. Check if your variable starts with the exact prefix shown on the Provider Details page (e.g., `API_STRIPE_COM_...`).