can1357/oh-my-pi · error · AIError.ValidationError

`context.tools` must be an array when present

Error message

`context.tools` must be an array when present

What it means

parseRequest accepts an optional `context.tools` array of tool definitions; when the key is present but is not an array (e.g. a single object, string, or null), this ValidationError is thrown. This keeps the tool schema well-formed before it reaches the streaming pipeline.

Source

Thrown at packages/ai/src/providers/pi-native-server.ts:131

	} else if (typeof obj.model === "object" && obj.model !== null) {
		const m = obj.model as Record<string, unknown>;
		if (typeof m.id === "string" && m.id.length > 0) modelId = m.id;
	}
	if (!modelId) throw new AIError.ValidationError("Missing `modelId` (or `model.id`) field");

	const context = obj.context;
	if (typeof context !== "object" || context === null || Array.isArray(context)) {
		throw new AIError.ValidationError("Missing `context` object");
	}
	const ctxObj = context as Record<string, unknown>;
	if (!Array.isArray(ctxObj.messages)) {
		throw new AIError.ValidationError("`context.messages` must be an array");
	}
	if (ctxObj.systemPrompt !== undefined && !Array.isArray(ctxObj.systemPrompt)) {
		throw new AIError.ValidationError("`context.systemPrompt` must be an array of strings when present");
	}
	if (ctxObj.tools !== undefined && !Array.isArray(ctxObj.tools)) {
		throw new AIError.ValidationError("`context.tools` must be an array when present");
	}

	const options: SimpleStreamOptions = {};
	const rawOpts = obj.options;
	if (typeof rawOpts === "object" && rawOpts !== null && !Array.isArray(rawOpts)) {
		const optsBag = options as Record<string, unknown>;
		for (const [k, v] of Object.entries(rawOpts)) {
			if (v === undefined || v === null) continue;
			if (!ALLOWED_OPTION_KEYS.has(k as keyof SimpleStreamOptions)) continue;
			optsBag[k] = v;
		}
	}

	// `stream` defaults to true — pi-native clients overwhelmingly stream, and
	// matching `streamProxy`'s implicit-stream behavior avoids a one-flag papercut.
	const stream = typeof obj.stream === "boolean" ? obj.stream : true;

	return {

View on GitHub (pinned to 9690622007)

Solutions

1. Wrap tool definitions in an array: `"tools":[{...}]`
2. Omit `tools` entirely rather than passing null when there are no tools
3. Validate each entry is a well-formed tool definition

Example fix

// before
{"context":{"messages":[...],"tools":{"name":"get_weather"}}}
// after
{"context":{"messages":[...],"tools":[{"name":"get_weather"}]}}

const t = body?.context?.tools;
if (t !== undefined && !Array.isArray(t)) throw new Error('context.tools must be an array when present');

function hasToolsArray(ctx: { tools?: unknown }): ctx is { tools?: unknown[] } {
  return ctx.tools === undefined || Array.isArray(ctx.tools);
}

try { const req = parseRequest(body); } catch (e) { if (e instanceof AIError.ValidationError && String(e.message).includes('`context.tools`')) return respond400('context.tools must be an array when present'); throw e; }

When it happens

Trigger: Sending `context:{"tools":{...}}` (a single tool object) or `"tools":null` instead of an array of tool definitions.

Common situations: Clients registering one tool and passing it directly; Anthropic/OpenAI tool objects copied without wrapping in an array; JSON templates with tools accidentally set to null when no tools are wanted (omit the key instead).

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• cachedContent cannot be combined with request-level ${incomp
• Missing `context` object
• `context.messages` must be an array
• `context.systemPrompt` must be an array of strings when pres
• Tool "${toolCall.name}" not found

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/a062feccd4a55c53. Report an issue: GitHub.