collection-storage-size

Retrieve storage size for a MongoDB collection to monitor database capacity and optimize resource allocation.

Instructions

Gets the size of the collection

Input Schema

TableJSON Schema

Name	Required	Description	Default
`database`	Yes	Database name
`collection`	Yes	Collection name

Implementation Reference

src/tools/mongodb/metadata/collectionStorageSize.ts:12-31 (handler)

Executes an aggregation pipeline using $collStats to compute the total storage size of the specified collection, scales the value to human-readable units, and returns a formatted text response.

protected async execute({ database, collection }: ToolArgs<typeof DbOperationArgs>): Promise<CallToolResult> {
    const provider = await this.ensureConnected();
    const [{ value }] = (await provider
        .aggregate(database, collection, [
            { $collStats: { storageStats: {} } },
            { $group: { _id: null, value: { $sum: "$storageStats.size" } } },
        ])
        .toArray()) as [{ value: number }];

    const { units, value: scaledValue } = CollectionStorageSizeTool.getStats(value);

    return {
        content: [
            {
                text: `The size of "${database}.${collection}" is \`${scaledValue.toFixed(2)} ${units}\``,
                type: "text",
            },
        ],
    };
}

src/tools/mongodb/mongodbTool.ts:11-14 (schema)

Zod schema defining the required input arguments for the tool: database and collection names.

export const DbOperationArgs = {
    database: z.string().describe("Database name"),
    collection: z.string().describe("Collection name"),
};

src/tools/mongodb/metadata/collectionStorageSize.ts:5-6 (registration)
The tool class definition with the 'name' property set to 'collection-storage-size', which identifies and registers the tool.
```
export class CollectionStorageSizeTool extends MongoDBToolBase {
    public name = "collection-storage-size";
```

src/tools/mongodb/metadata/collectionStorageSize.ts:33-50 (helper)

Custom error handling for cases where the collection does not exist (NamespaceNotFound), providing a user-friendly message.

protected handleError(
    error: unknown,
    args: ToolArgs<typeof this.argsShape>
): Promise<CallToolResult> | CallToolResult {
    if (error instanceof Error && "codeName" in error && error.codeName === "NamespaceNotFound") {
        return {
            content: [
                {
                    text: `The size of "${args.database}.${args.collection}" cannot be determined because the collection does not exist.`,
                    type: "text",
                },
            ],
            isError: true,
        };
    }

    return super.handleError(error, args);
}

src/tools/mongodb/metadata/collectionStorageSize.ts:52-68 (helper)

Utility function to convert raw storage size in bytes to a scaled human-readable value with appropriate units (bytes, KB, MB, GB).

private static getStats(value: number): { value: number; units: string } {
    const kb = 1024;
    const mb = kb * 1024;
    const gb = mb * 1024;

    if (value > gb) {
        return { value: value / gb, units: "GB" };
    }

    if (value > mb) {
        return { value: value / mb, units: "MB" };
    }
    if (value > kb) {
        return { value: value / kb, units: "KB" };
    }
    return { value, units: "bytes" };
}

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