Skip to content

fix(compat-oai): drop empty toolRequest chunks during tool-call streaming #5492

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
serhiizghama wants to merge 2 commits into
base: main
Choose a base branch
from
Open

fix(compat-oai): drop empty toolRequest chunks during tool-call streaming #5492

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b745365
fix(compat-oai): drop empty toolRequest chunks during tool-call strea…
serhiizghama Jun 9, 2026
da658ae
test(compat-oai): cover streaming tool_call continuation deltas
serhiizghama Jun 9, 2026
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
13 changes: 10 additions & 3 deletions js/plugins/compat-oai/src/model.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -433,9 +433,16 @@ export function fromOpenAIChunkChoice(
choice: ChatCompletionChunk.Choice,
jsonMode = false
): GenerateResponseData {
const toolRequestParts = choice.delta.tool_calls?.map((toolCall) =>
fromOpenAIToolCall(toolCall, choice)
);
// While streaming, OpenAI-compatible models emit the tool call's identity
// (id + function.name) only in the first delta; the following deltas carry
// incremental `arguments` fragments with no id and no name. Mapping those
// continuation deltas produced empty `{ toolRequest: { input: '' } }` chunks
// (see #5374). Keep only deltas that start a new tool call — the complete
// tool call (with assembled arguments) is reconstructed from the final
// response via `stream.finalChatCompletion()`.
const toolRequestParts = choice.delta.tool_calls
?.filter((toolCall) => toolCall.id || toolCall.function?.name)
.map((toolCall) => fromOpenAIToolCall(toolCall, choice));
Comment on lines +443 to +445

@gemini-code-assist gemini-code-assist Bot Jun 9, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

high

If a streaming chunk contains toolCall.id but toolCall.function is undefined (or toolCall.function.name is undefined), the current filter toolCall.id || toolCall.function?.name will evaluate to true.

This leads to two issues:

  1. If toolCall.function is undefined, fromOpenAIToolCall will throw a runtime error because of the check if (!toolCall.function) { throw Error(...) }.
  2. If toolCall.function is defined but toolCall.function.name is undefined, fromOpenAIToolCall will return a ToolRequestPart with name: undefined, which violates the type definition of ToolRequestPart (where name is a required string).

Filtering solely on toolCall.function?.name guarantees that both toolCall.function and toolCall.function.name are defined, preventing both the runtime crash and the invalid type output.

Suggested change
const toolRequestParts = choice.delta.tool_calls
?.filter((toolCall) => toolCall.id || toolCall.function?.name)
.map((toolCall) => fromOpenAIToolCall(toolCall, choice));
const toolRequestParts = choice.delta.tool_calls
?.filter((toolCall) => toolCall.function?.name)
.map((toolCall) => fromOpenAIToolCall(toolCall, choice));


// Build content array based on what's present in the delta
let content: Part[] = [];
Expand Down
62 changes: 62 additions & 0 deletions js/plugins/compat-oai/tests/compat_oai_test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -655,6 +655,68 @@ describe('fromOpenAiChunkChoice', () => {
finishReason: 'stop',
},
},
{
should:
'emit a tool request part for the first streaming tool_call delta',
chunkChoice: {
index: 0,
delta: {
role: 'assistant',
tool_calls: [
{
index: 0,
id: 'call_abc',
function: {
name: 'list_files',
arguments: '',
},
},
],
},
finish_reason: null,
},
expectedOutput: {
finishReason: 'unknown',
message: {
role: 'model',
content: [
{
toolRequest: {
name: 'list_files',
input: '',
ref: 'call_abc',
},
},
],
},
},
},
{
should:
'skip streaming tool_call argument-continuation deltas (no id, no name)',
chunkChoice: {
index: 0,
delta: {
role: 'assistant',
tool_calls: [
{
index: 0,
function: {
arguments: '{"path":',
},
},
],
} as any,
finish_reason: null,
},
expectedOutput: {
finishReason: 'unknown',
message: {
role: 'model',
content: [],
},
},
},
{
should: 'work with reasoning_content',
chunkChoice: {
Expand Down
Loading