fix: improve MCP tool error handling with retry logic and better messages #6191
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| Original file line number | Diff line number | Diff line change | ||||
|---|---|---|---|---|---|---|
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@@ -54,29 +54,54 @@ async function validateParams( | |||||
| return { isValid: false } | ||||||
| } | ||||||
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| // Validate server name format | ||||||
| const serverName = params.server_name.trim() | ||||||
| if (!serverName) { | ||||||
| cline.consecutiveMistakeCount++ | ||||||
| cline.recordToolError("use_mcp_tool") | ||||||
| await cline.say("error", "Server name cannot be empty or contain only whitespace") | ||||||
| pushToolResult(formatResponse.toolError("Invalid server name: cannot be empty")) | ||||||
| return { isValid: false } | ||||||
| } | ||||||
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| // Validate tool name format | ||||||
| const toolName = params.tool_name.trim() | ||||||
| if (!toolName) { | ||||||
| cline.consecutiveMistakeCount++ | ||||||
| cline.recordToolError("use_mcp_tool") | ||||||
| await cline.say("error", "Tool name cannot be empty or contain only whitespace") | ||||||
|
Contributor
There was a problem hiding this comment. Similarly, use i18n for the tool name error message rather than a literal string.
Suggested change
This comment was generated because it violated a code review rule: irule_C0ez7Rji6ANcGkkX. |
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| pushToolResult(formatResponse.toolError("Invalid tool name: cannot be empty")) | ||||||
| return { isValid: false } | ||||||
| } | ||||||
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| let parsedArguments: Record<string, unknown> | undefined | ||||||
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||||||
| if (params.arguments) { | ||||||
| try { | ||||||
| parsedArguments = JSON.parse(params.arguments) | ||||||
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||||||
| // Validate that arguments is an object (not array or primitive) | ||||||
| if ((parsedArguments !== null && typeof parsedArguments !== "object") || Array.isArray(parsedArguments)) { | ||||||
| throw new Error("Arguments must be a JSON object, not an array or primitive value") | ||||||
| } | ||||||
| } catch (error) { | ||||||
| cline.consecutiveMistakeCount++ | ||||||
| cline.recordToolError("use_mcp_tool") | ||||||
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| const errorMessage = error instanceof Error ? error.message : "Invalid JSON" | ||||||
| await cline.say("error", `Invalid JSON arguments for tool '${toolName}': ${errorMessage}`) | ||||||
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| pushToolResult( | ||||||
| formatResponse.toolError(`Invalid JSON arguments for ${serverName}.${toolName}: ${errorMessage}`), | ||||||
| ) | ||||||
| return { isValid: false } | ||||||
| } | ||||||
| } | ||||||
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||||||
| return { | ||||||
| isValid: true, | ||||||
| serverName, | ||||||
| toolName, | ||||||
| parsedArguments, | ||||||
| } | ||||||
| } | ||||||
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@@ -127,41 +152,74 @@ async function executeToolAndProcessResult( | |||||
| toolName, | ||||||
| }) | ||||||
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| let retryCount = 0 | ||||||
| const maxRetries = 3 | ||||||
| let lastError: Error | null = null | ||||||
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||||||
| while (retryCount <= maxRetries) { | ||||||
| try { | ||||||
| const mcpHub = cline.providerRef.deref()?.getMcpHub() | ||||||
| if (!mcpHub) { | ||||||
| throw new Error("MCP Hub is not available. Please ensure MCP servers are properly configured.") | ||||||
| } | ||||||
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| const toolResult = await mcpHub.callTool(serverName, toolName, parsedArguments) | ||||||
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| if (toolResult) { | ||||||
| const outputText = processToolContent(toolResult) | ||||||
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||||||
| if (outputText) { | ||||||
| await sendExecutionStatus(cline, { | ||||||
| executionId, | ||||||
| status: "output", | ||||||
| response: outputText, | ||||||
| }) | ||||||
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| const toolResultPretty = (toolResult.isError ? "Error:\n" : "") + outputText | ||||||
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| // Send completion status | ||||||
| await sendExecutionStatus(cline, { | ||||||
| executionId, | ||||||
| status: toolResult.isError ? "error" : "completed", | ||||||
| response: toolResultPretty, | ||||||
| error: toolResult.isError ? outputText : undefined, | ||||||
| }) | ||||||
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| await cline.say("mcp_server_response", toolResultPretty) | ||||||
| pushToolResult(formatResponse.toolResult(toolResultPretty)) | ||||||
| return | ||||||
| } | ||||||
| } | ||||||
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| // If we get here, toolResult was null/undefined | ||||||
| throw new Error(`No response received from MCP server '${serverName}' for tool '${toolName}'`) | ||||||
| } catch (error) { | ||||||
| lastError = error instanceof Error ? error : new Error(String(error)) | ||||||
| retryCount++ | ||||||
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| if (retryCount <= maxRetries) { | ||||||
| const delay = Math.min(1000 * Math.pow(2, retryCount - 1), 5000) // Exponential backoff with max 5s | ||||||
| await cline.say( | ||||||
| "error", | ||||||
| `MCP tool execution failed (attempt ${retryCount}/${maxRetries}). Retrying in ${delay / 1000}s...`, | ||||||
| ) | ||||||
| await new Promise((resolve) => setTimeout(resolve, delay)) | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| // All retries failed | ||||||
| const errorMessage = lastError?.message || "Unknown error occurred" | ||||||
| const userFriendlyError = `Failed to execute MCP tool '${toolName}' on server '${serverName}' after ${maxRetries} attempts. ${errorMessage}` | ||||||
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| await sendExecutionStatus(cline, { | ||||||
| executionId, | ||||||
| status: "error", | ||||||
| error: userFriendlyError, | ||||||
| }) | ||||||
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| await cline.say("mcp_server_response", `Error: ${userFriendlyError}`) | ||||||
| pushToolResult(formatResponse.toolError(userFriendlyError)) | ||||||
| } | ||||||
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||||||
| export async function useMcpToolTool( | ||||||
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Consider using the translation function (t) for user‐facing error messages instead of hardcoding strings (e.g. 'Server name cannot be empty or contain only whitespace'). This will ensure consistency with i18n practices.
This comment was generated because it violated a code review rule: irule_C0ez7Rji6ANcGkkX.