Get Case Citations

Instructions

Implementation Reference

• src/server.ts:208-235 (registration)

  Registration of the 'get_case_citations' tool via server.registerTool, defining its metadata and handler.

  // 4. Case citator
  server.registerTool(
  	"get_case_citations",
  	{
  		annotations: { readOnlyHint: true },
  		description:
  			"Get citation information for a case: what it cites, what cites it, or what legislation it references. Note: the CanLII API currently only supports English for this endpoint; French requests will fall back to English.",
  		inputSchema: {
  			caseId: z.string().describe('Case ID (e.g. "1999canlii1527")'),
  			citationType: z
  				.enum(["citedCases", "citingCases", "citedLegislations"])
  				.describe("Type of citation data to retrieve"),
  			databaseId: z.string().describe('Database ID (e.g. "onca")'),
  			language: z
  				.enum(["en", "fr"])
  				.default("en")
  				.describe("Response language (currently only 'en' is supported by the API)"),
  		},
  		title: "Get Case Citations",
  	},
  	async ({ databaseId, caseId, citationType }) => {
  		try {
  			return ok(await request(`/caseCitator/en/${databaseId}/${caseId}/${citationType}`));
  		} catch (e) {
  			return err(String(e));
  		}
  	},
  );

• src/server.ts:211-227 (schema)

  Input schema for 'get_case_citations' with caseId, citationType, databaseId, and language parameters using Zod validation.

  {
  	annotations: { readOnlyHint: true },
  	description:
  		"Get citation information for a case: what it cites, what cites it, or what legislation it references. Note: the CanLII API currently only supports English for this endpoint; French requests will fall back to English.",
  	inputSchema: {
  		caseId: z.string().describe('Case ID (e.g. "1999canlii1527")'),
  		citationType: z
  			.enum(["citedCases", "citingCases", "citedLegislations"])
  			.describe("Type of citation data to retrieve"),
  		databaseId: z.string().describe('Database ID (e.g. "onca")'),
  		language: z
  			.enum(["en", "fr"])
  			.default("en")
  			.describe("Response language (currently only 'en' is supported by the API)"),
  	},
  	title: "Get Case Citations",
  },

• src/server.ts:228-234 (handler)

  Handler function for 'get_case_citations' that makes a GET request to /caseCitator/en/{databaseId}/{caseId}/{citationType} and returns the JSON result.

  async ({ databaseId, caseId, citationType }) => {
  	try {
  		return ok(await request(`/caseCitator/en/${databaseId}/${caseId}/${citationType}`));
  	} catch (e) {
  		return err(String(e));
  	}
  },

• src/server.ts:50-71 (helper)

  The canliiRequest helper that performs the actual HTTP call to the CanLII API with rate limiting and error handling.

  async function canliiRequest(
  	apiKey: string,
  	path: string,
  	params: Record<string, string> = {},
  ): Promise<unknown> {
  	await acquireSlot();
  	try {
  		const url = new URL(`${BASE_URL}${path}`);
  		url.searchParams.set("api_key", apiKey);
  		for (const [k, v] of Object.entries(params)) {
  			if (v !== undefined && v !== "") url.searchParams.set(k, v);
  		}
  		const res = await fetch(url.toString());
  		if (!res.ok) {
  			const body = await res.text();
  			throw new Error(`CanLII API ${res.status}: ${body}`);
  		}
  		return await res.json();
  	} finally {
  		releaseSlot();
  	}
  }

• src/server.ts:73-84 (helper)

  Helper functions ok() and err() that format successful/error responses for tool output.

  type ToolResult = {
  	content: Array<{ type: "text"; text: string }>;
  	isError?: boolean;
  };
  
  function ok(data: unknown): ToolResult {
  	return { content: [{ text: JSON.stringify(data, null, 2), type: "text" }] };
  }
  
  function err(message: string): ToolResult {
  	return { content: [{ text: message, type: "text" }], isError: true };
  }