can1357/oh-my-pi · error · ToolError

Unknown tool from js runtime: ${name}

Error message

Unknown tool from js runtime: ${name}

What it means

The eval tool bridge resolves tool names against the current `ToolSession` (via `getToolForEvalBridge` or `getToolByName`). When no tool with the requested name exists, `getTool` throws this `ToolError`. It surfaces to JS eval code that calls a session tool under a wrong/unknown name.

Source

Thrown at packages/coding-agent/src/eval/js/tool-bridge.ts:42

			text: string;
			details?: unknown;
			images?: Array<{ mimeType: string; data: string }>;
			hasError?: boolean;
	  };
function toolResultHasError(result: AgentToolResult): boolean {
	if ((result as { isError?: unknown }).isError === true) {
		return true;
	}
	if (!(result.details && typeof result.details === "object")) {
		return false;
	}
	return (result.details as { isError?: unknown }).isError === true;
}

function getTool(session: ToolSession, name: string): AgentTool {
	const tool = session.getToolForEvalBridge ? session.getToolForEvalBridge(name) : session.getToolByName?.(name);
	if (!tool) {
		throw new ToolError(`Unknown tool from js runtime: ${name}`);
	}
	return tool;
}

function normalizeArgs(args: unknown): unknown {
	if (!args || typeof args !== "object" || Array.isArray(args)) {
		return args;
	}
	const record = { ...(args as Record<string, unknown>) };
	if (record[INTENT_FIELD] === undefined) {
		record[INTENT_FIELD] = "js prelude";
	}
	return record;
}

function summarizeToolResult(
	name: string,
	args: unknown,

View on GitHub (pinned to 9690622007)

Solutions

1. Verify the exact tool name — list available tools from the session before calling
2. Check agent/MCP config so the tool is actually registered and enabled
3. Guard eval code: check tool availability (if supported) before invoking, or wrap the call in try-catch for ToolError

Example fix

// before
await tool("read_file", { path: "x.ts" });
// after
await tool("read", { filePath: "x.ts" }); // correct registered name

// discover valid tool names first
const names = session.tools?.map(t => t.name) ?? [];
if (!names.includes(name)) throw new Error(`Tool "${name}" not available; have: ${names.join(", ")}`);

try {
  await tool(name, args);
} catch (err) {
  if (err instanceof ToolError && /Unknown tool from js runtime/.test(err.message)) {
    // fall back to listing tools or a default tool
  }
}

When it happens

Trigger: Calling `tool("someName", ...)` or `callSessionTool` from JS eval code with a name that is not registered on the session (typo, tool disabled by config, or MCP server not connected).

Common situations: Typo in the tool name; a tool filtered out by permission/allow-list config; an MCP tool missing because the server failed to start; using a builtin name that only exists in other agent versions.

Related errors

• \`${name}\` cannot run through the eval bridge; call the dir
• agent() received invalid arguments: ${result.summary}
• agent() blocked: turn token budget exhausted (${turnBudget.s
• ${failureMessage}${recoveryHint} (subagent failure: ${policy
• agent() isolated apply failed for ${result.id}${summary ? `:

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/ec27d47fbe40e0db. Report an issue: GitHub.