Skip to content

fix(gemini): split model messages with mixed signed/unsigned thoughtSignature parts #11950

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
weijiafu14 wants to merge 1 commit into
base: main
Choose a base branch
from
Open

fix(gemini): split model messages with mixed signed/unsigned thoughtSignature parts #11950

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
36 changes: 30 additions & 6 deletions src/api/transform/gemini-format.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -180,6 +180,17 @@ export function convertAnthropicContentToGemini(
return parts
}

/**
* Convert an Anthropic message to Gemini Content objects.
*
* For model (assistant) messages, Gemini requires that parts WITH thoughtSignature
* and parts WITHOUT are NOT mixed in the same Content. When a message contains
* both (e.g. text without signature + functionCall with signature), we split them
* into separate Content objects: unsigned first, signed second.
*
* Reference: https://ai.google.dev/gemini-api/docs/thought-signatures
* "Don't merge one part with a signature with another part without a signature"
*/
export function convertAnthropicMessageToGemini(
message: Anthropic.Messages.MessageParam,
options?: { includeThoughtSignatures?: boolean; toolIdToName?: Map<string, string> },
Expand All @@ -190,10 +201,23 @@ export function convertAnthropicMessageToGemini(
return []
}

return [
{
role: message.role === "assistant" ? "model" : "user",
parts,
},
]
const role = message.role === "assistant" ? "model" : "user"

// Only split model messages — user messages don't have thoughtSignature concerns
if (role === "model" && parts.length > 1) {
const signed = parts.filter((p) => "thoughtSignature" in p && (p as PartWithThoughtSignature).thoughtSignature)
const unsigned = parts.filter(
(p) => !("thoughtSignature" in p && (p as PartWithThoughtSignature).thoughtSignature),
)

if (signed.length > 0 && unsigned.length > 0) {
// Split: unsigned parts first (text), then signed parts (functionCall/thinking)
return [
{ role, parts: unsigned },
{ role, parts: signed },
]
}
}

return [{ role, parts }]
}
Loading