diff --git a/wave-mcp/src/tools/accounting.ts b/wave-mcp/src/tools/accounting.ts
new file mode 100644
index 0000000..5a7921e
--- /dev/null
+++ b/wave-mcp/src/tools/accounting.ts
@@ -0,0 +1,406 @@
+import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
+import { z } from "zod";
+import { WaveClient } from "../services/wave-client.js";
+import { WaveAccount, WaveTransaction } from "../types.js";
+import { DEFAULT_PAGE_SIZE, MAX_PAGE_SIZE } from "../constants.js";
+
+interface AccountsData {
+  business: {
+    accounts: {
+      pageInfo: { currentPage: number; totalPages: number; totalCount: number };
+      edges: Array<{ node: WaveAccount }>;
+    };
+  };
+}
+
+interface TransactionCreateData {
+  moneyTransactionCreate: {
+    didSucceed: boolean;
+    inputErrors: Array<{ code: string; message: string; path: string[] }>;
+    transaction?: WaveTransaction;
+  };
+}
+
+interface UserData {
+  user: { id: string; defaultEmail: string };
+}
+
+const ACCOUNT_FIELDS = `
+  id name description displayId
+  type { name value normalBalanceType }
+  subtype { name value }
+  currency { code }
+  isArchived sequence normalBalanceType
+`;
+
+function formatAccountMarkdown(a: WaveAccount): string[] {
+  const lines = [
+    `## ${a.name} (${a.displayId})`,
+    `- **ID**: ${a.id}`,
+    `- **Type**: ${a.type.name} / ${a.subtype.name}`,
+    `- **Currency**: ${a.currency.code}`,
+  ];
+  if (a.isArchived) lines.push("- **Status**: Archived");
+  if (a.description) lines.push(`- **Description**: ${a.description}`);
+  lines.push("");
+  return lines;
+}
+
+export function registerAccountingTools(server: McpServer, client: WaveClient): void {
+  // ── wave_get_user ─────────────────────────────────────────────────────────
+
+  server.registerTool(
+    "wave_get_user",
+    {
+      title: "Get Wave User",
+      description: `Get the authenticated Wave user's ID and email. Useful for verifying token validity and identifying the logged-in user.
+
+Args:
+  - response_format ('markdown' | 'json'): Output format (default: 'markdown')
+
+Returns:
+  User ID and default email address.`,
+      inputSchema: z.object({
+        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
+      }),
+      annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true },
+    },
+    async ({ response_format }) => {
+      try {
+        const data = await client.query<UserData>(`query { user { id defaultEmail } }`);
+        const user = data.user;
+
+        let text: string;
+        if (response_format === "json") {
+          text = JSON.stringify(user, null, 2);
+        } else {
+          text = `# Wave User\n\n- **ID**: ${user.id}\n- **Email**: ${user.defaultEmail}`;
+        }
+
+        return { content: [{ type: "text", text }], structuredContent: user };
+      } catch (error) {
+        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
+      }
+    }
+  );
+
+  // ── wave_list_accounts ────────────────────────────────────────────────────
+
+  server.registerTool(
+    "wave_list_accounts",
+    {
+      title: "List Wave Accounts",
+      description: `List chart of accounts for a Wave business, optionally filtered by type.
+
+Args:
+  - businessId (string): Wave business ID
+  - page (number): Page number (default: 1)
+  - pageSize (number): Items per page, 1-100 (default: 20)
+  - type ('ASSET' | 'LIABILITY' | 'EQUITY' | 'INCOME' | 'EXPENSE'): Filter by account type (optional)
+  - includeArchived (boolean): Include archived accounts (default: false)
+  - response_format ('markdown' | 'json'): Output format (default: 'markdown')
+
+Returns:
+  Paginated chart of accounts with type, subtype, currency, and display ID.`,
+      inputSchema: z.object({
+        businessId: z.string().describe("Wave business ID"),
+        page: z.number().int().min(1).default(1).describe("Page number"),
+        pageSize: z.number().int().min(1).max(MAX_PAGE_SIZE).default(DEFAULT_PAGE_SIZE).describe("Items per page"),
+        type: z.enum(["ASSET", "LIABILITY", "EQUITY", "INCOME", "EXPENSE"]).optional().describe("Filter by account type"),
+        includeArchived: z.boolean().default(false).describe("Include archived accounts"),
+        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
+      }),
+      annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true },
+    },
+    async ({ businessId, page, pageSize, type, includeArchived, response_format }) => {
+      try {
+        const data = await client.query<AccountsData>(`
+          query($businessId: ID!, $page: Int!, $pageSize: Int!) {
+            business(id: $businessId) {
+              accounts(page: $page, pageSize: $pageSize) {
+                pageInfo { currentPage totalPages totalCount }
+                edges { node { ${ACCOUNT_FIELDS} } }
+              }
+            }
+          }
+        `, { businessId, page, pageSize });
+
+        const { pageInfo, edges } = data.business.accounts;
+        let accounts = edges.map((e) => e.node);
+
+        // Client-side filtering
+        if (type) accounts = accounts.filter((a) => a.type.value === type);
+        if (!includeArchived) accounts = accounts.filter((a) => !a.isArchived);
+
+        if (!accounts.length) {
+          return { content: [{ type: "text", text: "No accounts found matching the criteria." }] };
+        }
+
+        const result = {
+          total: pageInfo.totalCount,
+          count: accounts.length,
+          page: pageInfo.currentPage,
+          totalPages: pageInfo.totalPages,
+          has_more: pageInfo.currentPage < pageInfo.totalPages,
+          next_page: pageInfo.currentPage < pageInfo.totalPages ? pageInfo.currentPage + 1 : undefined,
+          accounts,
+        };
+
+        let text: string;
+        if (response_format === "json") {
+          text = JSON.stringify(result, null, 2);
+        } else {
+          const lines = [`# Chart of Accounts (${pageInfo.totalCount} total, page ${pageInfo.currentPage}/${pageInfo.totalPages})`, ""];
+          // Group by type
+          const grouped: Record<string, WaveAccount[]> = {};
+          for (const a of accounts) {
+            const t = a.type.name;
+            if (!grouped[t]) grouped[t] = [];
+            grouped[t].push(a);
+          }
+          for (const [typeName, typeAccounts] of Object.entries(grouped)) {
+            lines.push(`### ${typeName}`, "");
+            for (const a of typeAccounts) lines.push(...formatAccountMarkdown(a));
+          }
+          text = lines.join("\n");
+        }
+
+        return {
+          content: [{ type: "text", text: WaveClient.truncate(text) }],
+          structuredContent: result,
+        };
+      } catch (error) {
+        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
+      }
+    }
+  );
+
+  // ── wave_create_transaction ───────────────────────────────────────────────
+
+  server.registerTool(
+    "wave_create_transaction",
+    {
+      title: "Create Wave Transaction",
+      description: `Create a money transaction (deposit or withdrawal) in Wave accounting.
+
+A transaction requires:
+1. An anchor account (typically a bank or credit card account) with a direction
+2. One or more line items that categorize the transaction
+
+The anchor is the primary account (e.g., your bank account). Line items describe what the money was for (e.g., an expense account).
+
+Direction values:
+  - For anchor: 'DEPOSIT' (money in) or 'WITHDRAWAL' (money out)
+  - For line items: 'INCREASE' or 'DECREASE' relative to the account's normal balance
+
+Args:
+  - businessId (string): Wave business ID
+  - description (string): Transaction description/memo
+  - anchorAccountId (string): Bank or credit card account ID
+  - anchorAmount (number): Transaction amount (positive)
+  - anchorDirection ('DEPOSIT' | 'WITHDRAWAL'): Money in or out of anchor account
+  - anchorDate (string): Date in YYYY-MM-DD format
+  - lineItems (array): Categorization items
+    - accountId (string): Account to categorize against
+    - amount (number): Amount for this line item
+    - balance ('INCREASE' | 'DECREASE'): Effect on the line item account
+    - description (string): Line item description (optional)
+  - response_format ('markdown' | 'json'): Output format (default: 'markdown')
+
+Returns:
+  Created transaction details or validation errors.`,
+      inputSchema: z.object({
+        businessId: z.string().describe("Wave business ID"),
+        description: z.string().optional().describe("Transaction description/memo"),
+        anchorAccountId: z.string().describe("Bank or credit card account ID"),
+        anchorAmount: z.number().positive().describe("Transaction amount (positive number)"),
+        anchorDirection: z.enum(["DEPOSIT", "WITHDRAWAL"]).describe("DEPOSIT = money in, WITHDRAWAL = money out"),
+        anchorDate: z.string().regex(/^\d{4}-\d{2}-\d{2}$/).describe("Transaction date (YYYY-MM-DD)"),
+        lineItems: z.array(z.object({
+          accountId: z.string().describe("Account ID for categorization"),
+          amount: z.number().positive().describe("Amount for this line item"),
+          balance: z.enum(["INCREASE", "DECREASE"]).describe("Effect on this account's balance"),
+          description: z.string().optional().describe("Line item description"),
+        })).min(1).describe("Line items categorizing the transaction"),
+        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
+      }),
+      annotations: { readOnlyHint: false, destructiveHint: false, idempotentHint: false, openWorldHint: true },
+    },
+    async ({ businessId, description, anchorAccountId, anchorAmount, anchorDirection, anchorDate, lineItems, response_format }) => {
+      try {
+        const input: Record<string, unknown> = {
+          businessId,
+          externalId: `mcp-${Date.now()}`,
+          date: anchorDate,
+          income: anchorDirection === "DEPOSIT" ? {
+            accountId: anchorAccountId,
+            amount: anchorAmount,
+            description,
+          } : undefined,
+          expense: anchorDirection === "WITHDRAWAL" ? {
+            accountId: anchorAccountId,
+            amount: anchorAmount,
+            description,
+          } : undefined,
+          lineItems: lineItems.map((li) => ({
+            accountId: li.accountId,
+            amount: li.amount,
+            balance: li.balance,
+            description: li.description,
+          })),
+        };
+
+        // Remove undefined keys
+        if (!input.income) delete input.income;
+        if (!input.expense) delete input.expense;
+
+        const data = await client.query<TransactionCreateData>(`
+          mutation($input: MoneyTransactionCreateInput!) {
+            moneyTransactionCreate(input: $input) {
+              didSucceed
+              inputErrors { code message path }
+              transaction {
+                id description notes
+                createdAt modifiedAt
+              }
+            }
+          }
+        `, { input });
+
+        const result = data.moneyTransactionCreate;
+        if (!result.didSucceed) {
+          const errs = result.inputErrors.map((e) => `  - ${e.path?.join(".") ?? "field"}: ${e.message}`).join("\n");
+          return { content: [{ type: "text", text: `Failed to create transaction:\n${errs}` }] };
+        }
+
+        let text: string;
+        if (response_format === "json") {
+          text = JSON.stringify(result.transaction, null, 2);
+        } else {
+          text = [
+            `Transaction created successfully!`,
+            `- **ID**: ${result.transaction?.id}`,
+            `- **Description**: ${result.transaction?.description ?? description ?? "N/A"}`,
+            `- **Amount**: ${WaveClient.formatCurrency(anchorAmount, "")} (${anchorDirection})`,
+            `- **Date**: ${anchorDate}`,
+          ].join("\n");
+        }
+
+        return { content: [{ type: "text", text }], structuredContent: result.transaction };
+      } catch (error) {
+        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
+      }
+    }
+  );
+
+  // ── wave_list_currencies ──────────────────────────────────────────────────
+
+  server.registerTool(
+    "wave_list_currencies",
+    {
+      title: "List Wave Currencies",
+      description: `List all currencies supported by Wave (ISO 4217). Useful for finding valid currency codes to use when creating customers or invoices.
+
+Args:
+  - response_format ('markdown' | 'json'): Output format (default: 'markdown')
+
+Returns:
+  List of all supported currencies with code, symbol, and name.`,
+      inputSchema: z.object({
+        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
+      }),
+      annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true },
+    },
+    async ({ response_format }) => {
+      try {
+        const data = await client.query<{
+          currencies: Array<{ code: string; symbol: string; name: string; plural: string }>;
+        }>(`
+          query {
+            currencies {
+              code symbol name plural
+            }
+          }
+        `);
+
+        const currencies = data.currencies;
+
+        let text: string;
+        if (response_format === "json") {
+          text = JSON.stringify({ count: currencies.length, currencies }, null, 2);
+        } else {
+          const lines = [`# Supported Currencies (${currencies.length})`, ""];
+          for (const c of currencies) {
+            lines.push(`- **${c.code}** ${c.symbol} — ${c.name}`);
+          }
+          text = lines.join("\n");
+        }
+
+        return {
+          content: [{ type: "text", text: WaveClient.truncate(text) }],
+          structuredContent: { count: currencies.length, currencies },
+        };
+      } catch (error) {
+        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
+      }
+    }
+  );
+
+  // ── wave_list_countries ───────────────────────────────────────────────────
+
+  server.registerTool(
+    "wave_list_countries",
+    {
+      title: "List Wave Countries",
+      description: `List all countries and their provinces supported by Wave. Use this to find valid country and province codes for addresses.
+
+Args:
+  - response_format ('markdown' | 'json'): Output format (default: 'markdown')
+
+Returns:
+  List of countries with ISO codes and their provinces/states.`,
+      inputSchema: z.object({
+        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
+      }),
+      annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true },
+    },
+    async ({ response_format }) => {
+      try {
+        const data = await client.query<{
+          countries: Array<{
+            code: string;
+            name: string;
+            provinces: Array<{ code: string; name: string }>;
+          }>;
+        }>(`
+          query {
+            countries {
+              code name
+              provinces { code name }
+            }
+          }
+        `);
+
+        const countries = data.countries;
+
+        let text: string;
+        if (response_format === "json") {
+          text = JSON.stringify({ count: countries.length, countries }, null, 2);
+        } else {
+          const lines = [`# Supported Countries (${countries.length})`, ""];
+          for (const c of countries) {
+            lines.push(`- **${c.code}** — ${c.name} (${c.provinces.length} provinces/states)`);
+          }
+          text = lines.join("\n");
+        }
+
+        return {
+          content: [{ type: "text", text: WaveClient.truncate(text) }],
+          structuredContent: { count: countries.length, countries },
+        };
+      } catch (error) {
+        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
+      }
+    }
+  );
+}