get_latest_glucose

Retrieve the most recent glucose reading for a user, including value, unit, timestamp, and source, to monitor blood sugar levels for diabetes management.

Instructions

Get the most recent glucose/blood sugar reading for a user. Returns value, unit, timestamp, and source.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`userId`	No	User identifier. Defaults to user_12345abcdef67890 if not specified.

Implementation Reference

src/api-client.ts:74-96 (handler)

Core handler implementation in HealthDataAPI class. Fetches the latest glucose reading via HTTP GET to backend /api/samples/latest endpoint, handles 404 by returning null, maps response to GlucoseReading interface.

async getLatestGlucose(userId: string): Promise<GlucoseReading | null> {
  try {
    const response = await this.client.get('/api/samples/latest', {
      params: {
        userId,
        type: 'BloodGlucose',
      },
    });

    const sample = response.data;
    return {
      value: sample.value,
      unit: sample.unit,
      date: sample.start_date,
      source: sample.source,
    };
  } catch (error: any) {
    if (error.response?.status === 404) {
      return null;
    }
    throw error;
  }
}

src/api-client.ts:3-7 (schema)
Type definition for GlucoseReading, used as return type for getLatestGlucose and structure for response data.
```
export interface GlucoseReading {
  value: number;
  unit: string;
  date: string;
  source: string;
```

src/index.ts:57-71 (registration)

MCP Tool registration in stdio server, defines name, description, and input schema for get_latest_glucose.

{
  name: 'get_latest_glucose',
  description:
    'Get the most recent glucose/blood sugar reading for a user. Returns value, unit, timestamp, and source.',
  inputSchema: {
    type: 'object',
    properties: {
      userId: {
        type: 'string',
        description: `User identifier. Defaults to ${DEFAULT_USER_ID || 'configured user'} if not specified.`,
      },
    },
    required: [],
  },
},

src/index.ts:164-195 (handler)

MCP tool call dispatcher in stdio server. Calls api.getLatestGlucose, handles null response, formats JSON output for MCP response.

case 'get_latest_glucose': {
  const reading = await api.getLatestGlucose(userId);

  if (!reading) {
    return {
      content: [
        {
          type: 'text',
          text: 'No glucose readings found for this user.',
        },
      ],
    };
  }

  return {
    content: [
      {
        type: 'text',
        text: JSON.stringify(
          {
            value: reading.value,
            unit: reading.unit,
            date: reading.date,
            source: reading.source,
          },
          null,
          2
        ),
      },
    ],
  };
}

src/http-server.ts:101-113 (registration)

MCP Tool registration in HTTP SSE server.

name: 'get_latest_glucose',
description:
  'Get the most recent glucose/blood sugar reading for a user. Returns value, unit, timestamp, and source.',
inputSchema: {
  type: 'object',
  properties: {
    userId: {
      type: 'string',
      description: `User identifier. Defaults to ${DEFAULT_USER_ID || 'configured user'} if not specified.`,
    },
  },
  required: [],
},

MCP Glucose Server