Function dbgWriteRequest

internal/tui/debuglog.go:119–146

dbgWriteRequest records, per LLM round, what newest-first packing actually sent: how much of history survived the budget and how many tool outputs are truncated. The message bodies are already captured as user/assistant/ tool_result records, so this logs only the packing decisions those per-message

(model string, ctxSize, budget, historyLen int, packed []chmctx.Message)

// records cannot show: what the model saw versus what was dropped. packed
// includes the prepended system message; historyLen is the pre-pack history.
func dbgWriteRequest(model string, ctxSize, budget, historyLen int, packed []chmctx.Message) {
	if !dbgEnabled() {
		return
	}
	// packed[0] is the prepended system message (buildMessages always prepends
	// it). Count AND sum over history messages only (packed[1:]) so the token
	// figure matches the message count and is directly comparable to budget,
	// which is the *history* budget (ctx.Budget already subtracts the system and
	// tool reservations). Summing the ~3k-token system prompt into a "packed=1
	// msgs" line would read as if that one history message were 3k tokens.
	tokens, truncated := 0, 0
	for _, msg := range packed[1:] {
		tokens += msg.Tokens()
		if strings.Contains(msg.Content, "───── truncated:") {
			truncated++
		}
	}
	note := ""
	if truncated > 0 {
		note = fmt.Sprintf(" · %d tool output(s) truncated", truncated)
	}
	// kept = packed minus the system message; dropped covers both budget
	// eviction and orphan-tool drops.
	kept := len(packed) - 1
	dbgWritef("request",
		"model=%s · ctx=%d (history budget=%d) · history=%d msgs → packed=%d msgs (~%d tokens) · dropped=%d oldest%s",
		model, ctxSize, budget, historyLen, kept, tokens, historyLen-kept, note)
}

// dbgWriteMessage records a chmctx.Message readably: content and tool calls
// each get a labeled section. No-op when logging is off, so callers needn't guard.