diff --git a/src/tools/skill-mcp/tools.ts b/src/tools/skill-mcp/tools.ts
index c06fa322bf..3d38790d5f 100644
--- a/src/tools/skill-mcp/tools.ts
+++ b/src/tools/skill-mcp/tools.ts
@@ -21,10 +21,10 @@ function validateOperationParams(args: SkillMcpArgs): OperationType {
   if (operations.length === 0) {
     throw new Error(
       `Missing operation. Exactly one of tool_name, resource_name, or prompt_name must be specified.\n\n` +
-      `Examples:\n` +
-      `  skill_mcp(mcp_name="sqlite", tool_name="query", arguments='{"sql": "SELECT * FROM users"}')\n` +
-      `  skill_mcp(mcp_name="memory", resource_name="memory://notes")\n` +
-      `  skill_mcp(mcp_name="helper", prompt_name="summarize", arguments='{"text": "..."}')`
+        `Examples:\n` +
+        `  skill_mcp(mcp_name="sqlite", tool_name="query", arguments='{"sql": "SELECT * FROM users"}')\n` +
+        `  skill_mcp(mcp_name="memory", resource_name="memory://notes")\n` +
+        `  skill_mcp(mcp_name="helper", prompt_name="summarize", arguments='{"text": "..."}')`,
     )
   }
 
@@ -33,12 +33,14 @@ function validateOperationParams(args: SkillMcpArgs): OperationType {
       args.tool_name && `tool_name="${args.tool_name}"`,
       args.resource_name && `resource_name="${args.resource_name}"`,
       args.prompt_name && `prompt_name="${args.prompt_name}"`,
-    ].filter(Boolean).join(", ")
+    ]
+      .filter(Boolean)
+      .join(", ")
 
     throw new Error(
       `Multiple operations specified. Exactly one of tool_name, resource_name, or prompt_name must be provided.\n\n` +
-      `Received: ${provided}\n\n` +
-      `Use separate calls for each operation.`
+        `Received: ${provided}\n\n` +
+        `Use separate calls for each operation.`,
     )
   }
 
@@ -47,7 +49,7 @@ function validateOperationParams(args: SkillMcpArgs): OperationType {
 
 function findMcpServer(
   mcpName: string,
-  skills: LoadedSkill[]
+  skills: LoadedSkill[],
 ): { skill: LoadedSkill; config: NonNullable<LoadedSkill["mcpConfig"]>[string] } | null {
   for (const skill of skills) {
     if (skill.mcpConfig && mcpName in skill.mcpConfig) {
@@ -75,7 +77,10 @@ function parseArguments(argsJson: string | Record<string, unknown> | undefined):
     return argsJson
   }
   try {
-    const parsed = JSON.parse(argsJson)
+    // Strip outer single quotes if present (common in LLM output)
+    const jsonStr = argsJson.startsWith("'") && argsJson.endsWith("'") ? argsJson.slice(1, -1) : argsJson
+
+    const parsed = JSON.parse(jsonStr)
     if (typeof parsed !== "object" || parsed === null) {
       throw new Error("Arguments must be a JSON object")
     }
@@ -84,8 +89,8 @@ function parseArguments(argsJson: string | Record<string, unknown> | undefined):
     const errorMessage = error instanceof Error ? error.message : String(error)
     throw new Error(
       `Invalid arguments JSON: ${errorMessage}\n\n` +
-      `Expected a valid JSON object, e.g.: '{"key": "value"}'\n` +
-      `Received: ${argsJson}`
+        `Expected a valid JSON object, e.g.: '{"key": "value"}'\n` +
+        `Received: ${argsJson}`,
     )
   }
 }
@@ -95,10 +100,8 @@ export function applyGrepFilter(output: string, pattern: string | undefined): st
   try {
     const regex = new RegExp(pattern, "i")
     const lines = output.split("\n")
-    const filtered = lines.filter(line => regex.test(line))
-    return filtered.length > 0 
-      ? filtered.join("\n") 
-      : `[grep] No lines matched pattern: ${pattern}`
+    const filtered = lines.filter((line) => regex.test(line))
+    return filtered.length > 0 ? filtered.join("\n") : `[grep] No lines matched pattern: ${pattern}`
   } catch {
     return output
   }
@@ -114,8 +117,14 @@ export function createSkillMcpTool(options: SkillMcpToolOptions): ToolDefinition
       tool_name: tool.schema.string().optional().describe("MCP tool to call"),
       resource_name: tool.schema.string().optional().describe("MCP resource URI to read"),
       prompt_name: tool.schema.string().optional().describe("MCP prompt to get"),
-      arguments: tool.schema.string().optional().describe("JSON string of arguments"),
-      grep: tool.schema.string().optional().describe("Regex pattern to filter output lines (only matching lines returned)"),
+      arguments: tool.schema
+        .union([tool.schema.string(), tool.schema.record(tool.schema.string(), tool.schema.unknown())])
+        .optional()
+        .describe("JSON string or object of arguments"),
+      grep: tool.schema
+        .string()
+        .optional()
+        .describe("Regex pattern to filter output lines (only matching lines returned)"),
     },
     async execute(args: SkillMcpArgs) {
       const operation = validateOperationParams(args)
@@ -125,9 +134,10 @@ export function createSkillMcpTool(options: SkillMcpToolOptions): ToolDefinition
       if (!found) {
         throw new Error(
           `MCP server "${args.mcp_name}" not found.\n\n` +
-          `Available MCP servers in loaded skills:\n` +
-          formatAvailableMcps(skills) + `\n\n` +
-          `Hint: Load the skill first using the 'skill' tool, then call skill_mcp.`
+            `Available MCP servers in loaded skills:\n` +
+            formatAvailableMcps(skills) +
+            `\n\n` +
+            `Hint: Load the skill first using the 'skill' tool, then call skill_mcp.`,
         )
       }