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get-hmr-events

Retrieve recent Hot Module Replacement events from the Vite dev server to track live code updates and modifications in real time.

Instructions

Retrieves recent HMR events

Input Schema

TableJSON Schema

Name	Required	Description	Default
`limit`	No	Maximum number of events to return

Implementation Reference

src/tools/hmr-tools.ts:22-50 (handler)

The async handler function for 'get-hmr-events' tool. It takes an optional 'limit' parameter, slices the lastHMREvents array accordingly, and returns the events as JSON text, or an error message if something fails.

  async ({ limit }) => {
    try {
      const eventsToReturn = limit ? lastHMREvents.slice(0, limit) : lastHMREvents;

      return {
        content: [
          {
            type: 'text',
            text: eventsToReturn.length > 0
              ? `Recent HMR events:\n${JSON.stringify(eventsToReturn, null, 2)}`
              : 'No HMR events detected yet.'
          }
        ]
      };
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      Logger.error(`Failed to get HMR events: ${errorMessage}`);
      return {
        content: [
          {
            type: 'text',
            text: `Failed to get HMR events: ${errorMessage}`
          }
        ],
        isError: true
      };
    }
  }
);

src/tools/hmr-tools.ts:19-21 (schema)
Input schema for the 'get-hmr-events' tool: an optional 'limit' number parameter that controls how many events to return.
```
{
  limit: z.number().optional().describe('Maximum number of events to return')
},
```

src/tools/hmr-tools.ts:11-51 (registration)

The registerHMRTools function that calls server.tool() to register 'get-hmr-events' with its schema and handler on the MCP server.

export function registerHMRTools(
  server: McpServer,
  lastHMREvents: HMREvent[]
) {
  // Recent HMR events retrieval tool
  server.tool(
    'get-hmr-events',
    'Retrieves recent HMR events',
    {
      limit: z.number().optional().describe('Maximum number of events to return')
    },
    async ({ limit }) => {
      try {
        const eventsToReturn = limit ? lastHMREvents.slice(0, limit) : lastHMREvents;

        return {
          content: [
            {
              type: 'text',
              text: eventsToReturn.length > 0
                ? `Recent HMR events:\n${JSON.stringify(eventsToReturn, null, 2)}`
                : 'No HMR events detected yet.'
            }
          ]
        };
      } catch (error) {
        const errorMessage = error instanceof Error ? error.message : String(error);
        Logger.error(`Failed to get HMR events: ${errorMessage}`);
        return {
          content: [
            {
              type: 'text',
              text: `Failed to get HMR events: ${errorMessage}`
            }
          ],
          isError: true
        };
      }
    }
  );
}

src/index.ts:85-85 (registration)
Invocation of registerHMRTools(server, lastHMREvents) from the main setup function, where lastHMREvents is the state array defined at line 26.
```
registerHMRTools(server, lastHMREvents);
```
src/types/hmr.ts:39-39 (helper)
The HMREvent type definition used by the tool's handler to type the event array.
```
export type HMREvent = HMRUpdate | HMRError | HMRBrowserError | { type: string; [key: string]: unknown };
```

Schema Changelog

Changes observed during successful MCP inspections.

First observedAug 15, 2025

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description bears the full burden of behavioral disclosure, but only restates the basic action. It doesn't mention side effects, whether events are cleared on retrieval, how 'recent' is defined, or the source/scope of the events. This leaves the agent unaware of important behavioral nuances.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence with no redundancy, and the core action is front-loaded. It is appropriately brief for a simple getter, though the lack of supporting context limits its overall usefulness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has no annotations, no output schema, and no description of return structure or scope. In a suite of browser tools with similar log/event retrieval functions, the description doesn't clarify what HMR events are or when to use this tool, making it insufficient for fully informed selection and invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already describes the only parameter, limit, with 100% coverage, so the baseline is 3. The description adds no extra meaning about limit usage, but none is required given the schema's clarity.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Retrieves recent HMR events' states a specific verb and object, clearly identifying the tool's function. It names a distinct resource type (HMR events) that isn't covered by any sibling, though it doesn't explicitly explain the acronym or contrast with alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no information about when to use this tool versus its siblings such as get-console-logs or monitor-network. There are no exclusions, preconditions, or context cues to guide selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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