fix: preserve empty reasoning_details arrays in multi-turn conversations - #487
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Always include reasoning_details in finish event metadata and reasoning-end providerMetadata, even when the accumulated array is empty. DeepSeek V4 and similar providers require the field to be sent back in subsequent turns to maintain conversation state.
Replace length>0 checks with Array.isArray checks so that an explicit [] from message-level providerOptions is treated as 'metadata present but empty' rather than 'metadata absent'. Preserve [] through dedup/signature-filter path.
…eaming, and #413 reasoning-delta metadata fix Restores four pieces of behavior that were inadvertently removed when the empty reasoning_details fix was applied: - #419: Defensive usage fallback in stream finish handler that copies openrouterUsage promptTokens/completionTokens into usage.inputTokens.total /outputTokens.total when the standard fields are still undefined after computeTokenUsage(). - #388: Model-level settings fallbacks (?? this.settings.X) for max_tokens, temperature, top_p, frequency_penalty, presence_penalty, top_k. - #443: eager_input_streaming forwarding from tool providerOptions to the function tool request body. - #413: Stop attaching accumulated reasoning_details snapshots to reasoning-start/reasoning-delta events to avoid payload bloat. The always-include behavior remains on reasoning-end and the stream finish event, which is the only place opencode-style consumers read it from. Keeps the legitimate empty reasoning_details fix in place so DeepSeek V4 and similar providers continue to receive the empty array on follow-up turns. Co-Authored-By: Robert Yeakel <robert.yeakel@openrouter.ai>
Restores the seven tests that were inadvertently deleted along with the empty reasoning_details fix and flips the reasoning-start/reasoning-delta providerMetadata assertions back to toBeUndefined() to lock in the restored #413 behavior. - 3 tests for eager_input_streaming forwarding from tool providerOptions. - 4 tests for the #419 defensive usage fallback in the stream finish handler. - Adjusts the two streaming reasoning_details tests to assert that reasoning-start and reasoning-delta events do NOT carry providerMetadata (the snapshot is exposed only on reasoning-end and the finish event). Co-Authored-By: Robert Yeakel <robert.yeakel@openrouter.ai>
Merged
This was referenced Apr 26, 2026
fix(cli,gateway): fully preserve DeepSeek reasoning_content across tool calls
Kilo-Org/kilocode#9502
Closed
This was referenced Apr 26, 2026
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Summary
Fixes a bug where
reasoning_details: [](empty array) was silently dropped in multi-turn conversations, breaking providers like DeepSeek V4 in thinking mode that require this field to be echoed back even when empty.Root cause
Multiple
length > 0guards in the conversion and streaming paths converted explicit emptyreasoning_details: []arrays toundefined, stripping a required signal that providers use to maintain conversation state.Changes
src/chat/index.tsopenrouterMetadata.reasoning_details, even when the accumulated array is empty (previously guarded bylength > 0)reasoning-endemit sites now always includeproviderMetadata.openrouter.reasoning_details, removing thelength > 0ternary that would drop the field entirelysrc/chat/convert-to-openrouter-chat-messages.tscandidateReasoningDetailsselection now usesArray.isArray(messageReasoningDetails)instead ofmessageReasoningDetails.length > 0— an explicit[]is now treated as "metadata was provided" rather than "metadata was absent"if (candidateReasoningDetails)guard no longer requireslength > 0; an empty candidate array still triggers the dedup/signature-filter blockfinalReasoningDetailsis now always set touniqueDetails(the deduplicated array), never collapsed toundefinedeffectiveReasoningstill requiresfinalReasoningDetails.length > 0— reasoning text is never sent alongside an empty details arrayTest plan
bun testpasses (401/401 tests)should preserve empty reasoning_details array from message-level providerOptions (DeepSeek V4)reasoning_details: []instead ofundefinedfor all cases where metadata was provided but produced no entriesRelated
DeepSeek V4 and similar providers in thinking mode return
reasoning_details: []on assistant turns with no visible reasoning tokens, and require this field to be included in subsequent requests. Omitting it causes 4xx errors on follow-up turns. Identified via opencode multi-turn testing.Reviewed by Perry