fix(tools): coerce stringified array params in tool calls

src/core/task/tools/handlers/DiagnosticsScanToolHandler.ts

@@ -11,6 +11,7 @@ import { telemetryService } from "@/services/telemetry"
 import { ToolResponse } from "../../index"
 import { IFullyManagedTool } from "../ToolExecutorCoordinator"
 import { ToolValidator } from "../ToolValidator"
+import { coerceToStringArray } from "../utils/coerceArray"
 import { TaskConfig } from "../types/TaskConfig"
 import { StronglyTypedUIHelpers } from "../types/UIHelpers"
 
@@ -23,13 +24,13 @@ export class DiagnosticsScanToolHandler implements IFullyManagedTool {
 	constructor(private validator: ToolValidator) {}
 
 	getDescription(block: ToolUse): string {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : [])
+		const relPaths = coerceToStringArray(block.params.paths)
 		const pathsText = relPaths.length > 0 ? ` for ${relPaths.map((p) => `'${p}'`).join(", ")}` : ""
 		return `[${block.name}${pathsText}]`
 	}
 
 	async handlePartialBlock(block: ToolUse, uiHelpers: StronglyTypedUIHelpers): Promise<void> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : [])
+		const relPaths = coerceToStringArray(block.params.paths)
 		const config = uiHelpers.getConfig()
 
 		const message = JSON.stringify({
@@ -55,7 +56,7 @@ export class DiagnosticsScanToolHandler implements IFullyManagedTool {
 			return await config.callbacks.sayAndCreateMissingParamError(this.name, "paths")
 		}
 
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : [])
+		const relPaths = coerceToStringArray(block.params.paths)
 		if (relPaths.length === 0) {
 			config.taskState.consecutiveMistakeCount++
 			return await config.callbacks.sayAndCreateMissingParamError(this.name, "paths")

src/core/task/tools/handlers/ExecuteCommandToolHandler.ts

@@ -17,6 +17,7 @@ import type { IFullyManagedTool } from "../ToolExecutorCoordinator"
 import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
+import { coerceToStringArray } from "../utils/coerceArray"
 import { isSafeCommand } from "../utils/CommandSafetyChecker"
 import { applyModelContentFixes } from "../utils/ModelContentProcessor"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
@@ -73,11 +74,7 @@ export class ExecuteCommandToolHandler implements IFullyManagedTool {
 	constructor(private validator: ToolValidator) {}
 
 	getDescription(block: ToolUse): string {
-		const commands = Array.isArray(block.params.commands)
-			? block.params.commands
-			: block.params.commands
-				? [block.params.commands as string]
-				: []
+		const commands = coerceToStringArray(block.params.commands)
 		const script = block.params.script as string | undefined
 		const language = block.params.language as string | undefined
 
@@ -99,23 +96,17 @@ export class ExecuteCommandToolHandler implements IFullyManagedTool {
 			return
 		}
 
-		const rawCommands = (block.params.commands as any) || []
+		const rawCommands = coerceToStringArray(block.params.commands)
 		const script = block.params.script as string | undefined
 		const language = (block.params.language as string | undefined) || "bash"
 
 		const commandsToProcess: { command: string; displayName?: string }[] = []
-		if (Array.isArray(rawCommands)) {
-			rawCommands.forEach((cmd: string) => {
-				if (cmd) {
-					commandsToProcess.push({
-						command: uiHelpers.removeClosingTag(block, "commands", cmd),
-					})
-				}
-			})
-		} else if (typeof rawCommands === "string" && rawCommands.trim() !== "") {
-			commandsToProcess.push({
-				command: uiHelpers.removeClosingTag(block, "commands", rawCommands),
-			})
+		for (const cmd of rawCommands) {
+			if (cmd) {
+				commandsToProcess.push({
+					command: uiHelpers.removeClosingTag(block, "commands", cmd),
+				})
+			}
 		}
 
 		if (script) {
@@ -158,7 +149,7 @@ export class ExecuteCommandToolHandler implements IFullyManagedTool {
 	}
 
 	async execute(config: TaskConfig, block: ToolUse): Promise<ToolResponse> {
-		const rawCommands = (block.params.commands as any) || []
+		const rawCommands = coerceToStringArray(block.params.commands)
 		const script = block.params.script as string | undefined
 		const language = (block.params.language as string | undefined) || "bash"
 
@@ -187,10 +178,10 @@ export class ExecuteCommandToolHandler implements IFullyManagedTool {
 		// Normalize to a list of commands
 		const commandsToProcess: { command: string; displayName?: string }[] = []
 
-		if (Array.isArray(rawCommands) && rawCommands.length > 0) {
-			rawCommands.forEach((cmd: string) => commandsToProcess.push({ command: cmd }))
-		} else if (typeof rawCommands === "string" && rawCommands.trim() !== "") {
-			commandsToProcess.push({ command: rawCommands })
+		for (const cmd of rawCommands) {
+			if (cmd) {
+				commandsToProcess.push({ command: cmd })
+			}
 		}
 
 		if (script) {

src/core/task/tools/handlers/FindSymbolReferencesToolHandler.ts

@@ -16,22 +16,23 @@ import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
+import { coerceFirstStringArray } from "../utils/coerceArray"
 
 export class FindSymbolReferencesToolHandler implements IFullyManagedTool {
 	readonly name = DiracDefaultTool.FIND_SYMBOL_REFERENCES
 
 	constructor(private validator: ToolValidator) {}
 
 	getDescription(block: ToolUse): string {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
-		const symbols = Array.isArray(block.params.symbols) ? block.params.symbols : (block.params.symbols ? [block.params.symbols as string] : (block.params.symbol ? [block.params.symbol as string] : []))
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
+		const symbols = coerceFirstStringArray(block.params.symbols, block.params.symbol)
 		const findType = (block.params.find_type as string) || "both"
 		return `[${block.name} for ${symbols.map((s) => `'${s}'`).join(", ")} in ${relPaths.map((p) => `'${p}'`).join(", ")}${findType !== "both" ? ` (type: ${findType})` : ""}]`
 	}
 
 	async handlePartialBlock(block: ToolUse, uiHelpers: StronglyTypedUIHelpers): Promise<void> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
-		const symbols = Array.isArray(block.params.symbols) ? block.params.symbols : (block.params.symbols ? [block.params.symbols as string] : (block.params.symbol ? [block.params.symbol as string] : []))
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
+		const symbols = coerceFirstStringArray(block.params.symbols, block.params.symbol)
 
 		const config = uiHelpers.getConfig()
 		if (config.isSubagentExecution) {
@@ -60,8 +61,8 @@ export class FindSymbolReferencesToolHandler implements IFullyManagedTool {
 	}
 
 	async execute(config: TaskConfig, block: ToolUse): Promise<ToolResponse> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
-		const symbols = Array.isArray(block.params.symbols) ? block.params.symbols : (block.params.symbols ? [block.params.symbols as string] : (block.params.symbol ? [block.params.symbol as string] : []))
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
+		const symbols = coerceFirstStringArray(block.params.symbols, block.params.symbol)
 		const findType = (block.params.find_type as "definition" | "reference" | "both") || "both"
 
 		const apiConfig = config.services.stateManager.getApiConfiguration()

src/core/task/tools/handlers/GetFileSkeletonToolHandler.ts

@@ -13,19 +13,20 @@ import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
+import { coerceFirstStringArray } from "../utils/coerceArray"
 
 export class GetFileSkeletonToolHandler implements IFullyManagedTool {
 	readonly name = DiracDefaultTool.GET_FILE_SKELETON
 
 	constructor(private validator: ToolValidator) {}
 
 	getDescription(block: ToolUse): string {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
 		return `[${block.name} for ${relPaths.map((p) => `'${p}'`).join(", ")}]`
 	}
 
 	async handlePartialBlock(block: ToolUse, uiHelpers: StronglyTypedUIHelpers): Promise<void> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
 		const config = uiHelpers.getConfig()
 		if (config.isSubagentExecution) {
 			return
@@ -50,7 +51,7 @@ export class GetFileSkeletonToolHandler implements IFullyManagedTool {
 	}
 
 	async execute(config: TaskConfig, block: ToolUse): Promise<ToolResponse> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
 		const apiConfig = config.services.stateManager.getApiConfiguration()
 		const currentMode = config.services.stateManager.getGlobalSettingsKey("mode")
 		const provider = (currentMode === "plan" ? apiConfig.planModeApiProvider : apiConfig.actModeApiProvider) as string

src/core/task/tools/handlers/GetFunctionToolHandler.ts

@@ -13,20 +13,21 @@ import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
+import { coerceToStringArray, coerceFirstStringArray } from "../utils/coerceArray"
 
 export class GetFunctionToolHandler implements IFullyManagedTool {
 	readonly name = DiracDefaultTool.GET_FUNCTION
 
 	constructor(private validator: ToolValidator) {}
 
 	getDescription(block: ToolUse): string {
-		const functionNames = Array.isArray(block.params.function_names) ? block.params.function_names : (block.params.function_names ? [block.params.function_names as string] : [])
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
+		const functionNames = coerceToStringArray(block.params.function_names)
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
 		return `[${block.name} for '${functionNames.join(", ")}' in ${relPaths.map((p) => `'${p}'`).join(", ")}]`
 	}
 	async handlePartialBlock(block: ToolUse, uiHelpers: StronglyTypedUIHelpers): Promise<void> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
-		const functionNames = Array.isArray(block.params.function_names) ? block.params.function_names : (block.params.function_names ? [block.params.function_names as string] : [])
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
+		const functionNames = coerceToStringArray(block.params.function_names)
 
 		const config = uiHelpers.getConfig()
 		if (config.isSubagentExecution) {
@@ -119,8 +120,8 @@ export class GetFunctionToolHandler implements IFullyManagedTool {
 
 
 		async execute(config: TaskConfig, block: ToolUse): Promise<ToolResponse> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : (block.params.path ? [block.params.path as string] : []))
-		const functionNames = Array.isArray(block.params.function_names) ? block.params.function_names : (block.params.function_names ? [block.params.function_names as string] : [])
+		const relPaths = coerceFirstStringArray(block.params.paths, block.params.path)
+		const functionNames = coerceToStringArray(block.params.function_names)
 
 		const apiConfig = config.services.stateManager.getApiConfiguration()
 		const currentMode = config.services.stateManager.getGlobalSettingsKey("mode")

src/core/task/tools/handlers/ListFilesToolHandler.ts

@@ -15,6 +15,7 @@ import type { IFullyManagedTool } from "../ToolExecutorCoordinator"
 import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
+import { coerceToStringArray } from "../utils/coerceArray"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
 
 // Sprint 2 — task E: async-by-default list_files when recursive=true.
@@ -39,20 +40,12 @@ export class ListFilesToolHandler implements IFullyManagedTool {
 	constructor(private validator: ToolValidator) {}
 
 	getDescription(block: ToolUse): string {
-		const relPaths = Array.isArray(block.params.paths)
-			? block.params.paths
-			: block.params.paths
-				? [block.params.paths as string]
-				: []
+		const relPaths = coerceToStringArray(block.params.paths)
 		return `[${block.name} for ${relPaths.map((p) => `'${p}'`).join(", ")}]`
 	}
 
 	async handlePartialBlock(block: ToolUse, uiHelpers: StronglyTypedUIHelpers): Promise<void> {
-		const relPaths = Array.isArray(block.params.paths)
-			? block.params.paths
-			: block.params.paths
-				? [block.params.paths as string]
-				: []
+		const relPaths = coerceToStringArray(block.params.paths)
 
 		// Get config access for services
 		const config = uiHelpers.getConfig()
@@ -177,11 +170,7 @@ export class ListFilesToolHandler implements IFullyManagedTool {
 	}
 
 	async execute(config: TaskConfig, block: ToolUse): Promise<ToolResponse> {
-		const relPaths = Array.isArray(block.params.paths)
-			? block.params.paths
-			: block.params.paths
-				? [block.params.paths as string]
-				: []
+		const relPaths = coerceToStringArray(block.params.paths)
 		const recursiveRaw = block.params.recursive
 		const recursive = String(recursiveRaw ?? "").toLowerCase() === "true"
 

src/core/task/tools/handlers/ReadFileToolHandler.ts

@@ -16,6 +16,7 @@ import type { IFullyManagedTool } from "../ToolExecutorCoordinator"
 import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
+import { coerceToStringArray } from "../utils/coerceArray"
 import { extractLastKnownHashFromHistory } from "../utils/extractLastKnownHash"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
 import { sliceContentLines } from "./readFilePagination"
@@ -43,7 +44,7 @@ export class ReadFileToolHandler implements IFullyManagedTool {
 	constructor(private validator: ToolValidator) {}
 
 	getDescription(block: ToolUse): string {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : [])
+		const relPaths = coerceToStringArray(block.params.paths)
 		const range =
 			block.params.start_line || block.params.end_line
 				? ` lines ${block.params.start_line || 1}-${block.params.end_line || "?"}`
@@ -52,7 +53,7 @@ export class ReadFileToolHandler implements IFullyManagedTool {
 	}
 
 	async handlePartialBlock(block: ToolUse, uiHelpers: StronglyTypedUIHelpers): Promise<void> {
-		const relPaths = Array.isArray(block.params.paths) ? block.params.paths : (block.params.paths ? [block.params.paths as string] : [])
+		const relPaths = coerceToStringArray(block.params.paths)
 		const config = uiHelpers.getConfig()
 		if (config.isSubagentExecution) {
 			return
@@ -90,11 +91,7 @@ export class ReadFileToolHandler implements IFullyManagedTool {
 	}
 
 	async execute(config: TaskConfig, block: ToolUse): Promise<ToolResponse> {
-		const relPaths = Array.isArray(block.params.paths)
-			? block.params.paths
-			: block.params.paths
-				? [block.params.paths as string]
-				: []
+		const relPaths = coerceToStringArray(block.params.paths)
 		const startLineNum = block.params.start_line ? Number.parseInt(String(block.params.start_line)) : undefined
 		const endLineNum = block.params.end_line ? Number.parseInt(String(block.params.end_line)) : undefined
 		const rawOffset = (block.params as any).offset

src/core/task/tools/handlers/RenameSymbolToolHandler.ts

@@ -21,6 +21,7 @@ import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
+import { coerceToStringArray } from "../utils/coerceArray"
 
 export class RenameSymbolToolHandler implements IFullyManagedTool {
 	readonly name = DiracDefaultTool.RENAME_SYMBOL
@@ -35,11 +36,7 @@ export class RenameSymbolToolHandler implements IFullyManagedTool {
 	getDescription(block: ToolUse): string {
 		const existingSymbol = block.params.existing_symbol as string
 		const newSymbol = block.params.new_symbol as string
-		const paths = Array.isArray(block.params.paths)
-			? block.params.paths
-			: block.params.paths
-				? [block.params.paths as string]
-				: []
+		const paths = coerceToStringArray(block.params.paths)
 		return `[${block.name} for '${existingSymbol}' to '${newSymbol}' in ${paths.map((p) => `'${p}'`).join(", ")}]`
 	}
 
@@ -50,11 +47,7 @@ export class RenameSymbolToolHandler implements IFullyManagedTool {
 			(block.params.existing_symbol as string) || "",
 		)
 		const newSymbol = uiHelpers.removeClosingTag(block, "new_symbol", (block.params.new_symbol as string) || "")
-		const paths = Array.isArray(block.params.paths)
-			? block.params.paths
-			: block.params.paths
-				? [block.params.paths as string]
-				: []
+		const paths = coerceToStringArray(block.params.paths)
 
 		const config = uiHelpers.getConfig()
 		if (config.isSubagentExecution) {
@@ -83,11 +76,7 @@ export class RenameSymbolToolHandler implements IFullyManagedTool {
 	async execute(config: TaskConfig, block: ToolUse): Promise<ToolResponse> {
 		const existingSymbol = block.params.existing_symbol as string
 		const newSymbol = block.params.new_symbol as string
-		const relPaths = Array.isArray(block.params.paths)
-			? block.params.paths
-			: block.params.paths
-				? [block.params.paths as string]
-				: []
+		const relPaths = coerceToStringArray(block.params.paths)
 
 		if (!existingSymbol || !newSymbol || relPaths.length === 0) {
 			config.taskState.consecutiveMistakeCount++

src/core/task/tools/handlers/SearchFilesToolHandler.ts

@@ -21,6 +21,7 @@ import type { ToolValidator } from "../ToolValidator"
 import type { TaskConfig } from "../types/TaskConfig"
 import type { StronglyTypedUIHelpers } from "../types/UIHelpers"
 import { ToolResultUtils } from "../utils/ToolResultUtils"
+import { coerceFirstStringArray } from "../utils/coerceArray"
 
 // Sprint 2 — task D: async-by-default search_files. Mirrors S2-C
 // (ExecuteCommandToolHandler): if ripgrep finishes within ASYNC_FAST_PATH_MS
@@ -35,15 +36,7 @@ export class SearchFilesToolHandler implements IFullyManagedTool {
 
 	constructor(private validator: ToolValidator) {}
 	private getRelPaths(params: any): string[] {
-		return Array.isArray(params.paths)
-			? params.paths
-			: params.paths
-				? [params.paths as string]
-				: Array.isArray(params.path)
-					? params.path
-					: params.path
-						? [params.path as string]
-						: []
+		return coerceFirstStringArray(params.paths, params.path)
 	}
 
 	getDescription(block: ToolUse): string {