Add support for /mcp schema to show full parameter schema as JSON (#1050)

Outputs a raw JSON version of the parameter names and descriptions as provided to the model, plus minor formatting adjustments to /mcp desc.

docs/cli/commands.md

@@ -27,6 +27,9 @@ Slash commands provide meta-level control over the CLI itself. They can typicall
     - **`nodesc`** or **`nodescriptions`**:
       - **Description:** Hides tool descriptions, showing only the tool names.
       - **Action:** Displays a compact list with only tool names.
+    - **`schema`**:
+      - **Description:** Shows full schema of tool parameters.
+      - **Action:** Displays the full JSON schema for the tool's configured parameters.
   - **Keyboard Shortcut:** Press **Ctrl+T** at any time to toggle between showing and hiding tool descriptions.
 
 - **`/clear`** (Shortcut: **Ctrl+L**)

packages/cli/src/ui/hooks/slashCommandProcessor.test.ts

@@ -1019,6 +1019,86 @@ Add any other context about the problem here.
     });
   });
 
+  describe('/mcp schema', () => {
+    it('should display tool schemas and descriptions', async () => {
+      // Mock MCP servers configuration with server description
+      const mockMcpServers = {
+        server1: {
+          command: 'cmd1',
+          description: 'This is a server description',
+        },
+      };
+
+      // Setup getMCPServerStatus mock implementation
+      vi.mocked(getMCPServerStatus).mockImplementation((serverName) => {
+        if (serverName === 'server1') return MCPServerStatus.CONNECTED;
+        return MCPServerStatus.DISCONNECTED;
+      });
+
+      // Setup getMCPDiscoveryState mock to return completed
+      vi.mocked(getMCPDiscoveryState).mockReturnValue(
+        MCPDiscoveryState.COMPLETED,
+      );
+
+      // Mock tools from server with descriptions
+      const mockServerTools = [
+        {
+          name: 'tool1',
+          description: 'This is tool 1 description',
+          schema: {
+            parameters: [{ name: 'param1', type: 'string' }],
+          },
+        },
+        {
+          name: 'tool2',
+          description: 'This is tool 2 description',
+          schema: {
+            parameters: [{ name: 'param2', type: 'number' }],
+          },
+        },
+      ];
+
+      mockConfig = {
+        ...mockConfig,
+        getToolRegistry: vi.fn().mockResolvedValue({
+          getToolsByServer: vi.fn().mockReturnValue(mockServerTools),
+        }),
+        getMcpServers: vi.fn().mockReturnValue(mockMcpServers),
+      } as unknown as Config;
+
+      const { handleSlashCommand } = getProcessor(true);
+      let commandResult: SlashCommandActionReturn | boolean = false;
+      await act(async () => {
+        commandResult = await handleSlashCommand('/mcp schema');
+      });
+
+      expect(mockAddItem).toHaveBeenNthCalledWith(
+        2,
+        expect.objectContaining({
+          type: MessageType.INFO,
+          text: expect.stringContaining('Configured MCP servers:'),
+        }),
+        expect.any(Number),
+      );
+
+      const message = mockAddItem.mock.calls[1][0].text;
+
+      // Check that server description is included
+      expect(message).toContain('Ready (2 tools)');
+      expect(message).toContain('This is a server description');
+
+      // Check that tool schemas are included
+      expect(message).toContain('tool 1 description');
+      expect(message).toContain('param1');
+      expect(message).toContain('string');
+      expect(message).toContain('tool 2 description');
+      expect(message).toContain('param2');
+      expect(message).toContain('number');
+
+      expect(commandResult).toBe(true);
+    });
+  });
+
   describe('/compress command', () => {
     it('should call tryCompressChat(true)', async () => {
       const { handleSlashCommand } = getProcessor();

packages/cli/src/ui/hooks/slashCommandProcessor.ts

@@ -238,6 +238,11 @@ export const useSlashCommandProcessor = (
           } else if (_args === 'nodesc' || _args === 'nodescriptions') {
             useShowDescriptions = false;
           }
+          // Check if the _subCommand includes a specific flag to show detailed tool schema
+          let useShowSchema = false;
+          if (_subCommand === 'schema' || _args === 'schema') {
+            useShowSchema = true;
+          }
 
           const toolRegistry = await config?.getToolRegistry();
           if (!toolRegistry) {
@@ -319,22 +324,18 @@ export const useSlashCommandProcessor = (
             }
 
             // Add server description with proper handling of multi-line descriptions
-            if (useShowDescriptions && server?.description) {
+            if ((useShowDescriptions || useShowSchema) && server?.description) {
               const greenColor = '\u001b[32m';
               const resetColor = '\u001b[0m';
 
-              const descLines = server.description.split('\n');
+              const descLines = server.description.trim().split('\n');
-              message += `: ${greenColor}${descLines[0]}${resetColor}`;
+              if (descLines) {
-              message += '\n';
+                message += ':\n';
-
+                for (let i = 0; i < descLines.length; i++) {
-              // If there are multiple lines, add proper indentation for each line
-              if (descLines.length > 1) {
-                for (let i = 1; i < descLines.length; i++) {
-                  // Skip empty lines at the end
-                  if (i === descLines.length - 1 && descLines[i].trim() === '')
-                    continue;
                   message += `    ${greenColor}${descLines[i]}${resetColor}\n`;
                 }
+              } else {
+                message += '\n';
               }
             } else {
               message += '\n';
@@ -345,35 +346,52 @@ export const useSlashCommandProcessor = (
 
             if (serverTools.length > 0) {
               serverTools.forEach((tool) => {
-                if (useShowDescriptions && tool.description) {
+                if (
+                  (useShowDescriptions || useShowSchema) &&
+                  tool.description
+                ) {
                   // Format tool name in cyan using simple ANSI cyan color
-                  message += `  - \u001b[36m${tool.name}\u001b[0m: `;
+                  message += `  - \u001b[36m${tool.name}\u001b[0m`;
 
                   // Apply green color to the description text
                   const greenColor = '\u001b[32m';
                   const resetColor = '\u001b[0m';
 
                   // Handle multi-line descriptions by properly indenting and preserving formatting
-                  const descLines = tool.description.split('\n');
+                  const descLines = tool.description.trim().split('\n');
-                  message += `${greenColor}${descLines[0]}${resetColor}\n`;
+                  if (descLines) {
-
+                    message += ':\n';
-                  // If there are multiple lines, add proper indentation for each line
+                    for (let i = 0; i < descLines.length; i++) {
-                  if (descLines.length > 1) {
-                    for (let i = 1; i < descLines.length; i++) {
-                      // Skip empty lines at the end
-                      if (
-                        i === descLines.length - 1 &&
-                        descLines[i].trim() === ''
-                      )
-                        continue;
                       message += `      ${greenColor}${descLines[i]}${resetColor}\n`;
                     }
+                  } else {
+                    message += '\n';
                   }
                   // Reset is handled inline with each line now
                 } else {
                   // Use cyan color for the tool name even when not showing descriptions
                   message += `  - \u001b[36m${tool.name}\u001b[0m\n`;
                 }
+                if (useShowSchema) {
+                  // Prefix the parameters in cyan
+                  message += `    \u001b[36mParameters:\u001b[0m\n`;
+                  // Apply green color to the parameter text
+                  const greenColor = '\u001b[32m';
+                  const resetColor = '\u001b[0m';
+
+                  const paramsLines = JSON.stringify(
+                    tool.schema.parameters,
+                    null,
+                    2,
+                  )
+                    .trim()
+                    .split('\n');
+                  if (paramsLines) {
+                    for (let i = 0; i < paramsLines.length; i++) {
+                      message += `      ${greenColor}${paramsLines[i]}${resetColor}\n`;
+                    }
+                  }
+                }
               });
             } else {
               message += '  No tools available\n';