Function dropDanglingToolCalls

internal/ctx/ctx.go:360–390

dropDanglingToolCalls removes any assistant message whose tool_calls include an id with no answering tool message in the kept slice: the mirror of dropOrphanTools. An assistant.tool_calls followed by fewer tool results than calls issued 400s every OpenAI-compatible backend with "missing tool respons

(kept []Message)

// TUI appends the assistant.tool_calls as soon as the round closes, but a Ctrl+C
// / stream-error / idle-stall then drops the pending calls so their tool results
// never arrive (see tui.endTurn). On the user's next request that dangling
// assistant would otherwise reach the wire and wedge the conversation until
// /clear. Empty ids count as unanswered: an unidentifiable call can't be paired.
func dropDanglingToolCalls(kept []Message) []Message {
	out := kept[:0]
	for i, m := range kept {
		if m.Role == RoleAssistant && len(m.ToolCalls) > 0 {
			// Answers must come from the contiguous run of tool messages that
			// follows THIS assistant, the only shape the wire accepts. A global
			// ID lookup would let a later turn's reused ID (index-derived
			// "call_0"-style IDs are common on local backends) vouch for an
			// aborted call here, sending the dangling assistant to the wire and
			// wedging the conversation with 400s until /clear.
			answered := map[string]bool{}
			for j := i + 1; j < len(kept) && kept[j].Role == RoleTool; j++ {
				if kept[j].ToolCallID != "" {
					answered[kept[j].ToolCallID] = true
				}
			}
			dangling := false
			for _, tc := range m.ToolCalls {
				if !answered[tc.ID] {
					dangling = true
					break
				}
			}
			if dangling {
				continue
			}
		}
		out = append(out, m)
	}
	return out
}