Skip to content

fix (ai): serialize parallel tool results in tool-call order #16572

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Kripu77 wants to merge 1 commit into
base: main
Choose a base branch
from
+309 −0
Open

fix (ai): serialize parallel tool results in tool-call order #16572

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions .changeset/tool-result-call-order.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
---
'ai': patch
---

fix (ai): serialize parallel tool results in tool-call order for deterministic prompt caching
277 changes: 277 additions & 0 deletions packages/ai/src/generate-text/to-response-messages.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1507,4 +1507,281 @@ describe('toResponseMessages', () => {
]
`);
});

describe('parallel tool result ordering', () => {
const weatherTool = tool({
description: 'Get weather information',
inputSchema: z.object({ city: z.string() }),
});

it('should order tool results by tool-call order, not completion order', async () => {
const result = await toResponseMessages({
content: [
{
type: 'tool-call',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
},
{
type: 'tool-call',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
},
// completion order: call-2 finished first
{
type: 'tool-result',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
output: '14C and rainy',
},
{
type: 'tool-result',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
output: '25C and sunny',
},
],
tools: { weather: weatherTool },
});

expect(result).toMatchInlineSnapshot(`
[
{
"content": [
{
"input": {
"city": "Tokyo",
},
"providerExecuted": undefined,
"providerOptions": undefined,
"toolCallId": "call-1",
"toolName": "weather",
"type": "tool-call",
},
{
"input": {
"city": "London",
},
"providerExecuted": undefined,
"providerOptions": undefined,
"toolCallId": "call-2",
"toolName": "weather",
"type": "tool-call",
},
],
"role": "assistant",
},
{
"content": [
{
"output": {
"type": "text",
"value": "25C and sunny",
},
"toolCallId": "call-1",
"toolName": "weather",
"type": "tool-result",
},
{
"output": {
"type": "text",
"value": "14C and rainy",
},
"toolCallId": "call-2",
"toolName": "weather",
"type": "tool-result",
},
],
"role": "tool",
},
]
`);
});

it('should keep tool results unchanged when they already match tool-call order', async () => {
const result = await toResponseMessages({
content: [
{
type: 'tool-call',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
},
{
type: 'tool-call',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
},
{
type: 'tool-result',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
output: '25C and sunny',
},
{
type: 'tool-result',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
output: '14C and rainy',
},
],
tools: { weather: weatherTool },
});

const toolMessage = result.find(message => message.role === 'tool');
expect(
toolMessage?.content.map(part =>
part.type === 'tool-result' ? part.toolCallId : part.type,
),
).toEqual(['call-1', 'call-2']);
});

it('should order tool errors together with tool results by tool-call order', async () => {
const result = await toResponseMessages({
content: [
{
type: 'tool-call',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
},
{
type: 'tool-call',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
},
// completion order: call-2 errored first
{
type: 'tool-error',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
error: 'City not found',
},
{
type: 'tool-result',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
output: '25C and sunny',
},
],
tools: { weather: weatherTool },
});

const toolMessage = result.find(message => message.role === 'tool');
expect(
toolMessage?.content.map(part =>
part.type === 'tool-result' ? part.toolCallId : part.type,
),
).toEqual(['call-1', 'call-2']);
});

it('should sort tool results without a matching tool call last, tie-broken by id', async () => {
const result = await toResponseMessages({
content: [
{
type: 'tool-call',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
},
{
type: 'tool-result',
toolCallId: 'call-3',
toolName: 'weather',
input: { city: 'Paris' },
output: '18C and cloudy',
},
{
type: 'tool-result',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
output: '25C and sunny',
},
{
type: 'tool-result',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
output: '14C and rainy',
},
],
tools: { weather: weatherTool },
});

const toolMessage = result.find(message => message.role === 'tool');
expect(
toolMessage?.content.map(part =>
part.type === 'tool-result' ? part.toolCallId : part.type,
),
).toEqual(['call-1', 'call-2', 'call-3']);
});

it('should not reorder the tool message when approval responses are present', async () => {
const result = await toResponseMessages({
content: [
{
type: 'tool-call',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
},
{
type: 'tool-call',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
},
{
type: 'tool-approval-request',
approvalId: 'approval-1',
toolCall: {
type: 'tool-call',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
},
},
// completion order: call-2's denial resolved first
{
type: 'tool-approval-response',
approvalId: 'approval-1',
approved: false,
reason: 'User denied access',
toolCall: {
type: 'tool-call',
toolCallId: 'call-2',
toolName: 'weather',
input: { city: 'London' },
},
},
{
type: 'tool-result',
toolCallId: 'call-1',
toolName: 'weather',
input: { city: 'Tokyo' },
output: '25C and sunny',
},
],
tools: { weather: weatherTool },
});

const toolMessage = result.find(message => message.role === 'tool');
expect(
toolMessage?.content.map(part =>
part.type === 'tool-result' ? part.toolCallId : part.type,
),
).toEqual(['tool-approval-response', 'call-2', 'call-1']);
});
});
});
27 changes: 27 additions & 0 deletions packages/ai/src/generate-text/to-response-messages.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -201,6 +201,33 @@ export async function toResponseMessages<TOOLS extends ToolSet>({
});
}

// Sort tool results into tool-call order: parallel results arrive in
// nondeterministic completion order, which breaks byte-sensitive provider
// prompt caching (#16567). Skipped when approval responses are present,
// since their ordering is position-dependent.
if (
toolResultContent.length > 1 &&
toolResultContent.every(part => part.type === 'tool-result')
) {
const toolCallRank = new Map(
inputContent
.filter(part => part.type === 'tool-call')
.map((part, index) => [part.toolCallId, index]),
);
toolResultContent.sort((a, b) => {
const aRank = toolCallRank.get(a.toolCallId);
const bRank = toolCallRank.get(b.toolCallId);
if (aRank != null && bRank != null) return aRank - bRank;
if (aRank != null) return -1;
if (bRank != null) return 1;
return a.toolCallId < b.toolCallId
? -1
: a.toolCallId > b.toolCallId
? 1
: 0;
});
}

if (toolResultContent.length > 0) {
responseMessages.push({
role: 'tool',
Expand Down