get_case_law_decisions

Instructions

Implementation Reference

• src/index.ts:224-252 (handler)

  The async handler function that executes the get_case_law_decisions tool logic: calls the CanLII caseBrowse API with language, databaseId, offset, resultCount, and date parameters, then parses the response with CasesResponseSchema.

  	async (params) => {
  		try {
  			const { language, databaseId, offset, resultCount, ...dateParams } = params;
  
  			const urlParams = new URLSearchParams({
  				api_key: apiKey,
  				offset: offset.toString(),
  				resultCount: resultCount.toString(),
  			});
  			buildDateParams(urlParams, dateParams);
  
  			const response = await apiFetch(
  				`https://api.canlii.org/v1/caseBrowse/${language}/${encodeURIComponent(databaseId)}/?${urlParams.toString()}`
  			);
  
  			if (!response.ok) {
  				return errorResponse(`Error: Failed to fetch case law decisions (${response.status})`);
  			}
  
  			const data = await response.json();
  			const parsed = CasesResponseSchema.parse(data);
  			return jsonResponse(parsed);
  		} catch (error) {
  			return errorResponse(
  				`Error: ${error instanceof Error ? error.message : "Unknown error"}`
  			);
  		}
  	}
  );

• src/index.ts:208-252 (registration)

  Tool registration via server.tool() with name 'get_case_law_decisions', description, and Zod schema for parameters (language enum, databaseId, offset, resultCount, date parameters).

  server.tool(
  	"get_case_law_decisions",
  	"List case law decisions from a specific court database. Use date filters to narrow results. " +
  	"Useful for browsing recent decisions from a specific court. " +
  	"Results are ordered by most recently added. Use get_case_metadata to get full details on a specific case.",
  	{
  		language: z.enum(["en", "fr"]).default("en")
  			.describe("Language: 'en' for English (default), 'fr' for French"),
  		databaseId: pathSegmentSchema
  			.describe("Court database ID (e.g., 'onsc' for Ontario Superior Court, 'onca' for Ontario Court of Appeal, 'csc-scc' for Supreme Court of Canada)"),
  		offset: z.number().default(0)
  			.describe("Start position for results (default 0 = most recent)"),
  		resultCount: z.number().max(10000).default(20)
  			.describe("Number of results to return (max 10,000, default 20)"),
  		...dateParametersSchema,
  	},
  	async (params) => {
  		try {
  			const { language, databaseId, offset, resultCount, ...dateParams } = params;
  
  			const urlParams = new URLSearchParams({
  				api_key: apiKey,
  				offset: offset.toString(),
  				resultCount: resultCount.toString(),
  			});
  			buildDateParams(urlParams, dateParams);
  
  			const response = await apiFetch(
  				`https://api.canlii.org/v1/caseBrowse/${language}/${encodeURIComponent(databaseId)}/?${urlParams.toString()}`
  			);
  
  			if (!response.ok) {
  				return errorResponse(`Error: Failed to fetch case law decisions (${response.status})`);
  			}
  
  			const data = await response.json();
  			const parsed = CasesResponseSchema.parse(data);
  			return jsonResponse(parsed);
  		} catch (error) {
  			return errorResponse(
  				`Error: ${error instanceof Error ? error.message : "Unknown error"}`
  			);
  		}
  	}
  );

• src/schema.ts:24-26 (schema)

  CasesResponseSchema - Zod schema defining the response shape: { cases: array of CaseSchema objects }. Used to parse the API response.

  export const CasesResponseSchema = z.object({
      cases: z.array(CaseSchema),
  }).passthrough();

• src/schema.ts:16-22 (schema)

  CaseSchema - Zod schema for individual case objects in the browse results (databaseId, caseId, title, citation, aiContentId).

  export const CaseSchema = z.object({
      databaseId: z.string(),
      caseId: CaseIdSchema,
      title: z.string(),
      citation: z.string(),
      aiContentId: z.record(z.string(), z.string()).optional(),
  }).passthrough();

• src/index.ts:105-114 (helper)

  dateParametersSchema - shared Zod schema object for date filter parameters (publishedBefore/After, modifiedBefore/After, changedBefore/After, decisionDateBefore/After) used by the tool via spread operator.

  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)"),
  };