v0.15.0 — GPT-6 / GPT-6.1 compatibility, default model gpt-6-luna

Since v0.14.0, the OpenAI provider supports the GPT-6 / GPT-6.1 model families and chunking follows the provider's real limits. This release is not byte-identical for deployments that do not set OPENAI_MODEL: they now run gpt-6-luna instead of gpt-4o, with the reasoning-model defaults below. To keep the previous behavior, set OPENAI_MODEL=gpt-4o (that snapshot shuts down on 2027-01-14). Deployments that set OPENAI_MODEL explicitly are unaffected by the default change.

GPT-6 / GPT-6.1 support (#43)

Model	Endpoint	Input ceiling	Default output cap
gpt-6-astra, gpt-6-sol, gpt-6-luna, gpt-6.1-sol	/responses (reasoning family)	922,000	32,768
chat-latest	/responses (reasoning family)	272,000	32,768
classic (gpt-4o, gpt-4.1, …)	/chat/completions	128,000	4096

The output cap is family-aware and resolved per request from the model the request uses; an explicit OPENAI_MAX_OUTPUT_TOKENS always wins. The token estimator now uses the o200k vocabulary for every reasoning-family model (it previously fell back to cl100k for gpt-5.6* and gpt-6*).

Default model is now gpt-6-luna

gpt-4o is no longer the default. Opt out with OPENAI_MODEL=gpt-4o until the 2027-01-14 shutdown.

Safer config on reasoning models

• Sampling parameters are dropped for reasoning models unless reasoning effort is explicitly none.
• Reasoning effort is forwarded verbatim. none / minimal are rejected by gpt-6-astra and gpt-6.1-sol; the rejection is surfaced with a remedy.
• Error mapping carries param and code. unsupported_value / unsupported_parameter map to a capability error with a targeted remedy. 429 insufficient_quota is no longer retried.

Chunking follows the provider

Chunking is coupled to MAX_TOKENS_PER_PR and the provider output cap. When the output cap exceeds the window, the pipeline falls back and emits pipeline.budget.output_cap_exceeds_window. Two side effects:

• Anthropic batches are now planned at or below MAX_TOKENS_PER_PR.
• A classic model with MAX_TOKENS_PER_PR above 128K rejects over-window batches up front (cap 123,904 by default).

Observability

• cache_write_tokens telemetry.
• Errors carry param / code; 5xx errors carry retry_after_ms.
• One shared "no findings on a reasoning model" notice replaces the three stale copies that recommended gpt-4.1 / OPENAI_TOOL_CHOICE=required; it now points at provider.usage.reasoning_tokens and the output cap.

Tests: 1134 across 58 files, all passing; 24/24 deterministic eval scenarios. Details: docs/model-compatibility.md and ADR-008.