feat(codex): gpt-6.1-sol joins the -900k opt-in (measured 922,000 ceiling)

agent/model_metadata.py

@@ -2918,7 +2918,15 @@ def _query_anthropic_context_length(model: str, base_url: str, api_key: str) ->
     # unprobed future gpt-6 descendant can never inherit this cap.
     "gpt-6-sol": 872_000,
     "gpt-6-luna": 872_000,
-    # gpt-6.1-sol: add once the codex lane serves it and max_context_window is measured (2026-09-29)
+    # GPT-6.1 Sol: the codex-sub catalog did NOT list the slug at measurement
+    # time, so there is no catalog max_context_window. Measured instead by
+    # request bisection against chatgpt.com/backend-api/codex/responses on
+    # 2026-09-30: 921,028 input tokens accepted, 921,998 rejected with
+    # context_length_exceeded -> 922,000 hard input ceiling (models.dev:
+    # 1,050,000 = 922,000 input + 128,000 output). 900K keeps the >=11K
+    # margin rule used for gpt-5.6. EXACT: no prefix, so -pro/-fast/other
+    # 6.1 descendants never inherit it.
+    "gpt-6.1-sol": 900_000,
 }
 
 # The advertised value the verified-above table is allowed to override.
@@ -2938,7 +2946,7 @@ def _query_anthropic_context_length(model: str, base_url: str, api_key: str) ->
     "gpt-6-astra",                # measured max_context_window 872,000
     "gpt-6-sol",                  # measured max_context_window 872,000
     "gpt-6-luna",                 # measured max_context_window 872,000
-    # gpt-6.1-sol: add once the codex lane serves it and max_context_window is measured (2026-09-29)
+    "gpt-6.1-sol",                # measured ceiling 922,000 (2026-09-30 bisection)
     "gpt-5.6-sol",
     "gpt-5.6-terra",
     "gpt-5.6-luna",

agent/usage_pricing.py

@@ -1833,7 +1833,7 @@ class CostResult:
 # GPT-6 Sol/Luna have no "-pro" variant (the 2026-09-22 launch shipped the
 # base slugs only), so alias ONLY the Hermes-side "-900k" Codex picker
 # variant — the suffix is stripped on the wire, so it is the same model.
-for _base_6 in ("gpt-6-sol", "gpt-6-luna"):
+for _base_6 in ("gpt-6-sol", "gpt-6.1-sol", "gpt-6-luna"):
     _OFFICIAL_DOCS_PRICING[("openai", f"{_base_6}-900k")] = _OFFICIAL_DOCS_PRICING[
         ("openai", _base_6)
     ]

hermes_cli/codex_models.py

@@ -20,6 +20,10 @@
     # they shipped (catalog visibility=list for both). Sol is the mid-tier
     # coding/agentic slug, Luna the cheap high-volume one.
     "gpt-6-sol",
+    # GPT-6.1 Sol (2026-09-29). Not yet listed by the account catalog
+    # (2026-09-30), but the Codex responses endpoint serves it (measured
+    # 921,028-token request OK), so it is curated + forward-compat'd here.
+    "gpt-6.1-sol",
     "gpt-6-luna",
     # GPT-5.6 series (Sol/Terra/Luna). The public API exposes "-pro"
     # variants, but the ChatGPT Codex OAuth backend rejects them with HTTP 400,
@@ -61,6 +65,7 @@
 _FORWARD_COMPAT_TEMPLATE_MODELS: List[tuple[str, tuple[str, ...]]] = [
     ("gpt-6-astra", ("gpt-5.6-sol", "gpt-5.5", "gpt-5.4")),
     ("gpt-6-sol", ("gpt-5.6-sol", "gpt-5.5", "gpt-5.4")),
+    ("gpt-6.1-sol", ("gpt-6-sol", "gpt-5.6-sol")),
     ("gpt-6-luna", ("gpt-5.6-luna", "gpt-5.6-sol", "gpt-5.5", "gpt-5.4")),
     ("gpt-5.6-sol", ("gpt-5.5", "gpt-5.4")),
     ("gpt-5.6-terra", ("gpt-5.5", "gpt-5.4")),

tests/agent/test_gpt61_sol_900k.py

@@ -0,0 +1,99 @@
+"""GPT-6.1 Sol joins the Codex ``-900k`` opt-in (2026-09-30).
+
+Measured 2026-09-30 by request bisection against
+chatgpt.com/backend-api/codex/responses: 921,028 input tokens accepted,
+921,998 rejected with ``context_length_exceeded`` -> 922,000 hard input
+ceiling. The variant grants 900,000 (>=11K margin, same rule as gpt-5.6).
+
+Behaviour contracts:
+- ``openai-codex/gpt-6.1-sol-900k`` strips to the wire slug ``gpt-6.1-sol``
+  and resolves to a 900,000 window;
+- bare ``gpt-6.1-sol`` keeps the advertised 272,000 (opt-in policy);
+- no prefix leak: ``gpt-6.1-sol-pro`` / ``-fast`` are not eligible;
+- picker surfaces ``gpt-6.1-sol-900k`` right after its base;
+- the ``-900k`` alias prices exactly like the base.
+"""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from agent.model_metadata import (
+    _verified_codex_ctx_for_slug,
+    get_model_context_length,
+    is_codex_900k_base,
+    is_codex_context_variant,
+    strip_codex_context_variant_suffix,
+)
+from agent.usage_pricing import get_pricing_entry
+
+
+def _codex_ctx(model: str) -> int:
+    fake_response = MagicMock()
+    fake_response.status_code = 401
+    fake_response.json.return_value = {}
+    import agent.model_metadata as mm
+
+    mm._codex_oauth_context_cache = {}
+    with patch("agent.model_metadata.requests.get", return_value=fake_response), \
+         patch("agent.model_metadata.get_cached_context_length", return_value=None), \
+         patch("agent.model_metadata.save_context_length"):
+        return get_model_context_length(
+            model=model,
+            base_url="https://chatgpt.com/backend-api/codex",
+            api_key="expired-token",
+            provider="openai-codex",
+        )
+
+
+def test_gpt61_sol_900k_strips_to_wire_slug():
+    assert is_codex_900k_base("gpt-6.1-sol") is True
+    assert is_codex_context_variant("openai-codex/gpt-6.1-sol-900k") is True
+    assert strip_codex_context_variant_suffix("gpt-6.1-sol-900k") == "gpt-6.1-sol"
+    assert (
+        strip_codex_context_variant_suffix("openai-codex/gpt-6.1-sol-900k")
+        == "openai-codex/gpt-6.1-sol"
+    )
+
+
+def test_gpt61_sol_900k_resolves_to_900k_window():
+    assert _verified_codex_ctx_for_slug("openai-codex/gpt-6.1-sol-900k") == 900_000
+    assert _codex_ctx("gpt-6.1-sol-900k") == 900_000
+    # Measured hard input ceiling is 922,000; the grant stays under it.
+    assert _verified_codex_ctx_for_slug("gpt-6.1-sol-900k") < 922_000
+
+
+def test_bare_gpt61_sol_keeps_advertised_272k():
+    assert _verified_codex_ctx_for_slug("gpt-6.1-sol") is None
+    assert _codex_ctx("gpt-6.1-sol") == 272_000
+
+
+@pytest.mark.parametrize("slug", ["gpt-6.1-sol-pro", "gpt-6.1-sol-fast", "gpt-6.1", "gpt-6.1-luna"])
+def test_no_prefix_leak(slug):
+    assert is_codex_900k_base(slug) is False
+    assert is_codex_context_variant(f"{slug}-900k") is False
+    assert strip_codex_context_variant_suffix(f"{slug}-900k") == f"{slug}-900k"
+
+
+def test_picker_surfaces_gpt61_sol_900k():
+    from hermes_cli.codex_models import (
+        DEFAULT_CODEX_MODELS,
+        _finalize_codex_models,
+        get_codex_model_ids,
+    )
+
+    assert "gpt-6.1-sol" in DEFAULT_CODEX_MODELS
+    ids = get_codex_model_ids()  # offline curated path
+    assert ids.index("gpt-6.1-sol-900k") == ids.index("gpt-6.1-sol") + 1
+    # A live catalog that only lists gpt-6-sol (true on 2026-09-30) still
+    # surfaces 6.1 via forward-compat.
+    out = _finalize_codex_models(["gpt-6-sol"])
+    assert "gpt-6.1-sol" in out and "gpt-6.1-sol-900k" in out
+
+
+@pytest.mark.parametrize("provider", ["openai", "openai-codex"])
+def test_gpt61_sol_900k_prices_like_base(provider):
+    base = get_pricing_entry("gpt-6.1-sol", provider=provider)
+    variant = get_pricing_entry("gpt-6.1-sol-900k", provider=provider)
+    assert base is not None and variant is not None
+    assert variant == base

tests/agent/test_gpt61_sol_prestage.py

@@ -4,7 +4,7 @@
 Behaviour contracts, not snapshots:
 - context resolves to the documented 1.05M window on the direct API and to
   the advertised 272K on the Codex OAuth offline fallback;
-- the ``-900k`` opt-in is NOT granted (no measured max_context_window yet);
+- the ``-900k`` opt-in is granted since 2026-09-30 (measured 922,000 ceiling);
 - pricing resolves to 6.1's own rates (cache read $0.10) while gpt-6-sol keeps
   its own ($0.20), on both the ``openai`` and ``openai-codex`` routes;
 - ``openai-codex/gpt-6.1-sol`` normalizes to the bare slug.
@@ -47,9 +47,10 @@ def test_gpt61_sol_codex_offline_fallback_is_advertised_272k():
     assert ctx == 272_000
 
 
-def test_gpt61_sol_not_900k_eligible_until_measured():
+def test_gpt61_sol_900k_eligible_once_measured():
+    # Flipped 2026-09-30: ceiling measured at 922,000 (see test_gpt61_sol_900k.py).
     assert is_codex_900k_base("gpt-6-sol") is True
-    assert is_codex_900k_base("gpt-6.1-sol") is False
+    assert is_codex_900k_base("gpt-6.1-sol") is True
 
 
 def test_gpt61_sol_prices_distinct_from_gpt6_sol():