fix(cli): restore automatic session titles

[marius-kilocode]

Automatic session titles can silently remain as timestamp placeholders when the configured small_model requires reasoning. The title request currently disables reasoning for Google models, so a model such as kilo/google/gemini-3.5-flash rejects it with HTTP 400: Reasoning is mandatory for this endpoint and cannot be disabled.

The title request also reuses the main session ID as its Kilo Gateway task ID. An upstream merge reverted the dedicated title ID, allowing the title request and main agent request to collide when they run concurrently.

Reproduction:

1. Configure small_model as kilo/google/gemini-3.5-flash.
2. Start a new session and send the first prompt.
3. Observe that the timestamp placeholder remains instead of being replaced by a generated title.
4. Inspect the CLI log and find the title request failing with the reasoning-mandatory HTTP 400. The title and main model requests also use the same x-kilo-task value based on the session ID.

This restores a dedicated title-<sessionID> task identity for title generation. Small requests now use model capabilities instead of model-name checks: non-reasoning models receive no reasoning option, while reasoning-capable models enable the provider-supported default without assuming that minimal, low, or another effort level exists.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

The fix is clean and the approach is sound. Both bugs are addressed correctly:

1. Task ID collision: KiloSessionPrompt.titleID returns title-<sessionID> which is used as the sessionID parameter to llm.stream for the title request — this becomes the x-kilo-task header value, isolating it from the concurrent main agent request.

2. Reasoning mandatory error: The model-name-based heuristic (hardcoded "google" string check + always-"minimal" effort) is replaced with model.capabilities.reasoning — if the model doesn't advertise reasoning support, no reasoning option is sent; if it does, { reasoning: { enabled: true } } defers to the provider's default effort level, which is safe across providers.

One observation (not a blocker): the openrouter and llmgateway branches also pick up the new capability-driven behavior alongside kilo-gateway. Before this PR those two branches unconditionally returned { reasoningEffort: "minimal" }. The behavior change for openrouter/llmgateway is not mentioned in the PR description but appears intentional — the same capability flag governs all three. If openrouter/llmgateway consumers ever set capabilities.reasoning: false, they'll now get {} instead of { reasoningEffort: "minimal" }, which is the correct outcome.

Tests in both session-title-generation.test.ts and the updated transform.test.ts are consistent with the implementation.

Files Reviewed (5 files)

• .changeset/calm-titles-return.md
• packages/opencode/src/kilocode/session/prompt.ts
• packages/opencode/src/provider/transform.ts
• packages/opencode/src/session/prompt.ts
• packages/opencode/test/kilocode/session-title-generation.test.ts
• packages/opencode/test/provider/transform.test.ts

Fix these issues in Kilo Cloud

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_{Reviewed by claude-4.6-sonnet-20260217 · 601,699 tokens}

_{Review guidance: REVIEW.md from base branch main}