get_legislation_databases

Instructions

Implementation Reference

• src/index.ts:399-432 (handler)

  The handler for the get_legislation_databases MCP tool. Fetches legislation databases from the CanLII API (v1/legislationBrowse) with optional language and date parameters, returns the parsed LegislationResponseSchema data.

  server.tool(
  	"get_legislation_databases",
  	"List all available legislation databases in Canada. Returns database IDs for browsing statutes and regulations. " +
  	"Key databases: ons (Ontario Statutes), onr (Ontario Regulations), cas (Canada Statutes), car (Canada Regulations), " +
  	"bcs (BC Statutes), abs (Alberta Statutes).",
  	{
  		language: z.enum(["en", "fr"]).default("en")
  			.describe("Language: 'en' for English (default), 'fr' for French"),
  		...dateParametersSchema,
  	},
  	async (params) => {
  		try {
  			const { language, ...dateParams } = params;
  			const urlParams = new URLSearchParams({ api_key: apiKey });
  			buildDateParams(urlParams, dateParams);
  
  			const response = await apiFetch(
  				`https://api.canlii.org/v1/legislationBrowse/${language}/?${urlParams.toString()}`
  			);
  
  			if (!response.ok) {
  				return errorResponse(`Error: Failed to fetch legislation databases (${response.status})`);
  			}
  
  			const data = await response.json();
  			const parsed = LegislationResponseSchema.parse(data);
  			return jsonResponse(parsed);
  		} catch (error) {
  			return errorResponse(
  				`Error: ${error instanceof Error ? error.message : "Unknown error"}`
  			);
  		}
  	}
  );

• src/schema.ts:69-78 (schema)

  Zod schema for legislation database items and the response shape (legislationDatabases array). Used to validate the API response.

  export const LegislationSchema = z.object({
      databaseId: z.string(),
      type: z.string(),
      jurisdiction: z.string(),
      name: z.string(),
  }).passthrough();
  
  export const LegislationResponseSchema = z.object({
      legislationDatabases: z.array(LegislationSchema),
  }).passthrough();

• src/index.ts:399-432 (registration)

  Registration of the tool via server.tool() with name 'get_legislation_databases' on the MCP server instance.

  server.tool(
  	"get_legislation_databases",
  	"List all available legislation databases in Canada. Returns database IDs for browsing statutes and regulations. " +
  	"Key databases: ons (Ontario Statutes), onr (Ontario Regulations), cas (Canada Statutes), car (Canada Regulations), " +
  	"bcs (BC Statutes), abs (Alberta Statutes).",
  	{
  		language: z.enum(["en", "fr"]).default("en")
  			.describe("Language: 'en' for English (default), 'fr' for French"),
  		...dateParametersSchema,
  	},
  	async (params) => {
  		try {
  			const { language, ...dateParams } = params;
  			const urlParams = new URLSearchParams({ api_key: apiKey });
  			buildDateParams(urlParams, dateParams);
  
  			const response = await apiFetch(
  				`https://api.canlii.org/v1/legislationBrowse/${language}/?${urlParams.toString()}`
  			);
  
  			if (!response.ok) {
  				return errorResponse(`Error: Failed to fetch legislation databases (${response.status})`);
  			}
  
  			const data = await response.json();
  			const parsed = LegislationResponseSchema.parse(data);
  			return jsonResponse(parsed);
  		} catch (error) {
  			return errorResponse(
  				`Error: ${error instanceof Error ? error.message : "Unknown error"}`
  			);
  		}
  	}
  );

• src/index.ts:105-114 (helper)

  Shared date parameters schema, spread into the tool's schema definition.

  const dateParametersSchema = {
  	publishedBefore: dateSchema.describe("Date first published on CanLII (YYYY-MM-DD)"),
  	publishedAfter: dateSchema.describe("Date first published on CanLII (YYYY-MM-DD)"),
  	modifiedBefore: dateSchema.describe("Date content last modified on CanLII (YYYY-MM-DD)"),
  	modifiedAfter: dateSchema.describe("Date content last modified on CanLII (YYYY-MM-DD)"),
  	changedBefore: dateSchema.describe("Date metadata or content last changed on CanLII (YYYY-MM-DD)"),
  	changedAfter: dateSchema.describe("Date metadata or content last changed on CanLII (YYYY-MM-DD)"),
  	decisionDateBefore: dateSchema.describe("Decision date upper bound (YYYY-MM-DD)"),
  	decisionDateAfter: dateSchema.describe("Decision date lower bound (YYYY-MM-DD)"),
  };

• src/index.ts:69-87 (helper)

  Utility function used by the handler to append date filter parameters to the API request URL.

  function buildDateParams(params: URLSearchParams, options: {
  	publishedBefore?: string;
  	publishedAfter?: string;
  	modifiedBefore?: string;
  	modifiedAfter?: string;
  	changedBefore?: string;
  	changedAfter?: string;
  	decisionDateBefore?: string;
  	decisionDateAfter?: string;
  }) {
  	if (options.publishedBefore) params.append('publishedBefore', options.publishedBefore);
  	if (options.publishedAfter) params.append('publishedAfter', options.publishedAfter);
  	if (options.modifiedBefore) params.append('modifiedBefore', options.modifiedBefore);
  	if (options.modifiedAfter) params.append('modifiedAfter', options.modifiedAfter);
  	if (options.changedBefore) params.append('changedBefore', options.changedBefore);
  	if (options.changedAfter) params.append('changedAfter', options.changedAfter);
  	if (options.decisionDateBefore) params.append('decisionDateBefore', options.decisionDateBefore);
  	if (options.decisionDateAfter) params.append('decisionDateAfter', options.decisionDateAfter);
  }