browse_legislation

Instructions

Implementation Reference

• src/index.ts:434-472 (handler)

  The main handler for the browse_legislation tool. It constructs a CanLII API URL for browsing legislation in a given database, calls apiFetch with rate limiting, validates the response with LegislationItemResponseSchema, and returns the result.

  // ============================================================
  // TOOL: browse_legislation
  // ============================================================
  server.tool(
  	"browse_legislation",
  	"List all legislation items in a specific database. Use to find legislation IDs for metadata lookup. " +
  	"Key statutes by database — ons: Children's Law Reform Act, Family Law Act, Employment Standards Act. " +
  	"cas: Divorce Act, Criminal Code, Canada Labour Code, Federal Child Support Guidelines.",
  	{
  		language: z.enum(["en", "fr"]).default("en")
  			.describe("Language: 'en' for English (default), 'fr' for French"),
  		databaseId: pathSegmentSchema
  			.describe("Legislation database ID (e.g., 'ons' for Ontario Statutes, 'cas' for Canada Statutes, 'onr' for Ontario Regulations)"),
  		...dateParametersSchema,
  	},
  	async (params) => {
  		try {
  			const { language, databaseId, ...dateParams } = params;
  			const urlParams = new URLSearchParams({ api_key: apiKey });
  			buildDateParams(urlParams, dateParams);
  
  			const response = await apiFetch(
  				`https://api.canlii.org/v1/legislationBrowse/${language}/${encodeURIComponent(databaseId)}/?${urlParams.toString()}`
  			);
  
  			if (!response.ok) {
  				return errorResponse(`Error: Failed to fetch legislation list (${response.status})`);
  			}
  
  			const data = await response.json();
  			const parsed = LegislationItemResponseSchema.parse(data);
  			return jsonResponse(parsed);
  		} catch (error) {
  			return errorResponse(
  				`Error: ${error instanceof Error ? error.message : "Unknown error"}`
  			);
  		}
  	}
  );

• src/index.ts:437-448 (registration)

  Registration of the browse_legislation tool on the MCP server with name, description, and input schema (language, databaseId, and date parameters).

  server.tool(
  	"browse_legislation",
  	"List all legislation items in a specific database. Use to find legislation IDs for metadata lookup. " +
  	"Key statutes by database — ons: Children's Law Reform Act, Family Law Act, Employment Standards Act. " +
  	"cas: Divorce Act, Criminal Code, Canada Labour Code, Federal Child Support Guidelines.",
  	{
  		language: z.enum(["en", "fr"]).default("en")
  			.describe("Language: 'en' for English (default), 'fr' for French"),
  		databaseId: pathSegmentSchema
  			.describe("Legislation database ID (e.g., 'ons' for Ontario Statutes, 'cas' for Canada Statutes, 'onr' for Ontario Regulations)"),
  		...dateParametersSchema,
  	},

• src/schema.ts:88-90 (schema)

  LegislationItemResponseSchema - zod schema used to parse the API response for browse_legislation, containing an array of legislation items.

  export const LegislationItemResponseSchema = z.object({
      legislations: z.array(LegislationItemSchema),
  }).passthrough();

• src/schema.ts:80-86 (schema)

  LegislationItemSchema - zod schema for each individual legislation item returned by browse_legislation (databaseId, legislationId, title, citation, type).

  export const LegislationItemSchema = z.object({
      databaseId: z.string(),
      legislationId: z.string(),
      title: z.string(),
      citation: z.string(),
      type: z.string(),
  }).passthrough();

• src/index.ts:69-87 (helper)

  buildDateParams helper function used by browse_legislation to add optional 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);
  }