Fix mcp tools: use __ instead of /

Author: jahooma

packages/agent-runtime/src/mcp-constants.ts

@@ -0,0 +1,12 @@
+/**
+ * Separator used between MCP server name and tool name.
+ * 
+ * LLM APIs (OpenRouter/Anthropic) only allow tool names matching the pattern
+ * ^[a-zA-Z0-9_-]{1,128}$, which doesn't include forward slashes.
+ * 
+ * We use double underscore as the separator since it's:
+ * - Allowed by the LLM API pattern
+ * - Unlikely to conflict with existing tool names
+ * - Clearly identifiable as a separator
+ */
+export const MCP_TOOL_SEPARATOR = '__'

packages/agent-runtime/src/mcp.ts

@@ -1,5 +1,7 @@
 import { convertJsonSchemaToZod } from 'zod-from-json-schema'
 
+import { MCP_TOOL_SEPARATOR } from './mcp-constants'
+
 import type { AgentTemplate } from './templates/types'
 import type { RequestMcpToolDataFn } from '@codebuff/common/types/contracts/client'
 import type { OptionalFields } from '@codebuff/common/types/function-params'
@@ -22,13 +24,16 @@ export async function getMCPToolData(
   const withDefaults = { writeTo: {}, ...params }
   const { toolNames, mcpServers, writeTo, requestMcpToolData } = withDefaults
 
+  // User-facing toolNames use '/' as separator (e.g., 'supabase/list_tables')
+  // but internally we use MCP_TOOL_SEPARATOR ('__') for LLM API compatibility
+  const USER_INPUT_SEPARATOR = '/'
   const requestedToolsByMcp: Record<string, string[] | undefined> = {}
   for (const t of toolNames) {
-    if (!t.includes('/')) {
+    if (!t.includes(USER_INPUT_SEPARATOR)) {
       continue
     }
-    const [mcpName, ...remaining] = t.split('/')
-    const toolName = remaining.join('/')
+    const [mcpName, ...remaining] = t.split(USER_INPUT_SEPARATOR)
+    const toolName = remaining.join(USER_INPUT_SEPARATOR)
     if (!requestedToolsByMcp[mcpName]) {
       requestedToolsByMcp[mcpName] = []
     }
@@ -45,7 +50,7 @@ export async function getMCPToolData(
         })
 
         for (const { name, description, inputSchema } of mcpData) {
-          writeTo[mcpName + '/' + name] = {
+          writeTo[mcpName + MCP_TOOL_SEPARATOR + name] = {
             inputSchema: convertJsonSchemaToZod(inputSchema as any) as any,
             endsAgentStep: true,
             description,

packages/agent-runtime/src/tools/tool-executor.ts

@@ -3,6 +3,7 @@ import { toolParams } from '@codebuff/common/tools/list'
 import { generateCompactId } from '@codebuff/common/util/string'
 import { cloneDeep } from 'lodash'
 
+import { MCP_TOOL_SEPARATOR } from '../mcp-constants'
 import { getMCPToolData } from '../mcp'
 import { getAgentShortName } from '../templates/prompts'
 import { codebuffToolHandlers } from './handlers/list'
@@ -274,7 +275,7 @@ export function parseRawCustomToolCall(params: {
 
   if (
     !(customToolDefs && toolName in customToolDefs) &&
-    !toolName.includes('/')
+    !toolName.includes(MCP_TOOL_SEPARATOR)
   ) {
     return {
       toolName,
@@ -370,8 +371,8 @@ export async function executeCustomToolCall(
     !(agentTemplate.toolNames as string[]).includes(toolCall.toolName) &&
     !fromHandleSteps &&
     !(
-      toolCall.toolName.includes('/') &&
-      toolCall.toolName.split('/')[0] in agentTemplate.mcpServers
+      toolCall.toolName.includes(MCP_TOOL_SEPARATOR) &&
+      toolCall.toolName.split(MCP_TOOL_SEPARATOR)[0] in agentTemplate.mcpServers
     )
   ) {
     // Emit an error event instead of tool call/result pair
@@ -415,15 +416,15 @@ export async function executeCustomToolCall(
         return null
       }
 
-      const toolName = toolCall.toolName.includes('/')
-        ? toolCall.toolName.split('/').slice(1).join('/')
+      const toolName = toolCall.toolName.includes(MCP_TOOL_SEPARATOR)
+        ? toolCall.toolName.split(MCP_TOOL_SEPARATOR).slice(1).join(MCP_TOOL_SEPARATOR)
         : toolCall.toolName
       const clientToolResult = await requestToolCall({
         userInputId,
         toolName,
         input: toolCall.input,
-        mcpConfig: toolCall.toolName.includes('/')
-          ? agentTemplate.mcpServers[toolCall.toolName.split('/')[0]]
+        mcpConfig: toolCall.toolName.includes(MCP_TOOL_SEPARATOR)
+          ? agentTemplate.mcpServers[toolCall.toolName.split(MCP_TOOL_SEPARATOR)[0]]
           : undefined,
       })
       return clientToolResult.output satisfies ToolResultOutput[]