fix(reasoning): gate reasoning_effort ladder to GLM-5.2+ on native zai provider

[rh-id]

Problem

Z.AI's official API (docs.z.ai) defines two distinct parameters:

• thinking: {"type": "enabled"|"disabled"} — the reasoning on/off toggle, supported by GLM-4.5 and above (with GLM-4.7 using forced thinking that cannot be disabled).
• reasoning_effort — the effort intensity ladder (max/xhigh/high/medium/low/minimal), supported by GLM-5.2 and above ONLY.

hermes-webui advertised the full 6-level reasoning_effort ladder (plus the none sentinel) for all 7 GLM models, because _candidate_supports_reasoning has an unconditional glm token match (api/config.py:3303, no version gate — unlike the GPT/Claude/Qwen branches above it which check major version) and _filter_reasoning_efforts_for_provider had no ZAI branch. Six of seven catalog models therefore showed a selector whose values Z.AI documents as GLM-5.2-exclusive, and the chosen value was forwarded toward an endpoint that silently ignores it.

Two bugs result:

• Bug 1 — reasoning_effort advertised for glm-5.1, glm-5, glm-5-turbo, glm-4.5, glm-4.5-flash (none support it; only glm-5.2 does).
• Bug 3 — glm-4.7 uses forced thinking (cannot be disabled per Z.AI docs), yet none and all effort levels were shown for it.

Fix (one targeted branch in the existing chokepoint)

Add a ZAI branch to _filter_reasoning_efforts_for_provider (api/config.py), mirroring the existing OpenAI/Gemini/Anthropic ceiling pattern:

if provider == "zai" and "glm" in bare:
    # GLM-4.7 family: forced thinking — reasoning is not configurable at all.
    if bare.startswith("glm-4.7"):
        return []
    m = re.search(r"glm-(\d+)(?:\D+(\d+))?", bare)
    if m:
        major = int(m.group(1))
        minor = int(m.group(2)) if m.group(2) else 0
        if (major, minor) >= (5, 2):
            return normalized  # GLM-5.2+ keeps the full ladder
    return []  # Everything else (4.5, 4.5-flash, 5, 5.1, 5-turbo)

Why this is the right scope (per guideline #1 — fix the class, not the instance)

• resolve_model_reasoning_efforts is the single source feeding both the UI dropdown options AND coerce_reasoning_effort_for_model clamping (both call through _filter_reasoning_efforts_for_provider). Fixing it here makes the dropdown and coercion agree automatically — no stored max will be degraded incorrectly, because it won't be offered in the first place.
• Mirrors the existing per-provider ceiling branches exactly (OpenAI GPT-5→xhigh, Gemini drop-max, pre-adaptive Claude drop-max).
• The glm family-detection heuristic at line 3303 is deliberately left unchanged — GLM models DO support the thinking on/off toggle at the family level (that flag drives the thinking-toggle UI too). The bug is specifically about the reasoning_effort intensity ladder, which is what the filter narrows.
• Scoped to the native zai provider only (aliases glm/z-ai/z.ai/zhipu all funnel to zai via _resolve_provider_alias, which the function already calls). Aggregator providers (openrouter/kilocode/custom) are untouched because they route through their own routers, not Z.AI's native endpoint.

Contract Routing

State layer touched: agent.reasoning_effort config (config.yaml) + UI dropdown options derived from resolve_model_reasoning_efforts.

Invariant proof: UI options and coercion now agree and match Z.AI's per-model docs — max/xhigh/high/medium/low/minimal are offered ONLY for GLM-5.2+ (whose accepted values match VALID_REASONING_EFFORTS exactly, max being the Z.AI default), and none is never offered for forced-thinking GLM-4.7. The downgrade ladder in coerce_reasoning_effort_for_model is unaffected because it only walks down from levels that ARE in the offered list.

Verification

Regression gate satisfied (per guideline #6): 12 of the 24 new tests fail before the fix (the full ladder was returned for every GLM model), all 24 pass after. Verified via stash/unstash on a clean tree.

24 new tests in tests/test_zai_reasoning_effort_gating.py:

• GLM-5.2 keeps the full 6-level ladder + none
• Future GLM ≥ 5.2 (5.3, 5.2-air, 6-pro, 6, 5.2.1) keep the full ladder
• Bug 1: pre-5.2 GLM (5.1, 5, 5-turbo, 4.5, 4.5-flash) → []
• Bug 3: GLM-4.7 + glm-4.7-air (forced thinking) → [] (no none either)
• All 4 aliases (glm/z-ai/z.ai/zhipu) resolve through the same gate
• Aggregators (kilocode/openrouter/custom:newapi) keep family-level reasoning — keeps existing test_generalized_model_families_and_suffixed_ids green
• Non-GLM models on zai provider are untouched by the GLM-specific gate
• Coercion agrees with advertising: stored max for glm-5.1 downgrades, max for glm-5.2 preserves

Broader suite: 129/129 pass across test_zai_reasoning_effort_gating + test_custom_provider_bare_model_reasoning + test_reasoning_effort_model_capabilities + test_reasoning_show_hide + test_catalog_has_provider_compound_ids + test_4413_seed_provider_models. No new lint errors (the 4 pre-existing ruff errors in api/config.py reproduce identically on clean master).

Pre-existing failure noted (NOT caused by this PR): test_custom_providers_in_panel.py::test_custom_provider_with_models fails under multi-file pytest ordering due to a provider-cache state leak across files — confirmed to reproduce identically on clean master. Passes in isolation.

Manual verification I could not do here

• Browser: confirm the reasoning chip dropdown shows all levels for glm-5.2 and shows nothing for glm-4.7/glm-4.5/glm-5.1 (requires UI + running backend).
• End-to-end: confirm a request to Z.AI for glm-5.2 with reasoning_effort: max succeeds, and for glm-4.5 the field is now omitted rather than silently ignored (requires GLM_API_KEY + network).

Out of scope — Bug 2 (separate issue)

There is a related gap I deliberately did not address here: no code path in this repo emits the thinking: {"type": "enabled"|"disabled"} request field for ZAI. That translation lives in the external run_agent/agent package (_build_api_kwargs()) or the Hermes Gateway server — neither of which is present in this repository (verified: import run_agent / import agent both raise ModuleNotFoundError; no sibling hermes-agent repo on disk). Investigating/implementing that belongs in a separate change against the agent tree, not here. Filing a separate issue to track it.

Sources

• Z.AI Core Parameters
• Z.AI Deep Thinking

[greptile-apps]

Greptile Summary

This PR gates the reasoning_effort intensity ladder to GLM-5.2+ on the native ZAI provider, fixing two bugs: pre-5.2 GLM models (5.1, 5, 5-turbo, 4.5, 4.5-flash) were incorrectly advertising the full ladder, and GLM-4.7 (forced thinking) was showing a none option that has no effect. It also addresses the previously-flagged coercion gaps — stored "none" for forced-thinking GLM-4.7 is now intercepted before the generic early-return, and non-max stored efforts for pre-5.2 GLM now coerce to "" rather than being forwarded to Z.AI unchanged.

• A new _zai_glm_classification helper introduces a clean three-tier model ("effort" / "thinking" / "forced") that is shared across the filter, coercion, and status paths, keeping them in sync.
• The thinking-toggle-only tier (GLM-4.5–5.1) is handled end-to-end: a new supports_thinking_toggle field flows from get_reasoning_status through the JS chip logic, keeping the on/off control visible (with a new "Default" option in the dropdown) even when the effort ladder is empty.
• set_reasoning_effort now accepts an empty string as "clear the override" to complete the two-way re-enable path.

Confidence Score: 4/5

The core fix is well-scoped and the previously-flagged coercion gaps are closed. One misleading comment in ui.js about default toggle behavior is the only remaining finding.

Both previously-flagged coercion issues are properly addressed: the 'none' bypass for GLM-4.7 is now intercepted before the generic early-return, and all non-max stored effort levels for pre-5.2 GLM now coerce to ''. The three-tier classification helper is clean and shared across the filter, coercion, and status surfaces. The one remaining finding is a documentation inaccuracy in ui.js — the undefined→true default for _currentReasoningToggleSupported is labeled 'prior behavior' but is actually a new policy that differs from old behavior (empty supported_efforts previously hid the chip).

static/ui.js — the _currentReasoningToggleSupported initialization comment should be updated to accurately describe the new default-to-visible policy.

Important Files Changed

Filename	Overview
api/config.py	Adds three new helper functions (_zai_glm_classification, _zai_glm_reasoning_efforts_supported, _zai_glm_thinking_toggle_supported), wires ZAI gate into _filter_reasoning_efforts_for_provider and coerce_reasoning_effort_for_model, adds forced-thinking early exit in resolve_model_reasoning_efforts, and extends get_reasoning_status with supports_thinking_toggle. The two previously-flagged coercion gaps are both addressed.
static/ui.js	Adds _currentReasoningToggleSupported state variable, updates chip visibility logic to OR effort ladder with thinking toggle, always surfaces Default (effort='') and None in the dropdown, and fixes the click handler to use opt presence rather than effort truthiness. The undefined→true default introduces a subtle behavioral change from the old code.
static/index.html	Adds a 'Default' option (data-effort='') as the first item in the reasoning dropdown, enabling the two-way thinking toggle for GLM-4.5–5.1 models.
tests/test_zai_reasoning_effort_gating.py	New test file with 24 parametrized tests covering the three-tier classification, alias resolution, aggregator passthrough, coercion agreement, and set_reasoning_effort empty-accept path.
tests/test_reasoning_chip_js_behaviour.py	Adds two new test classes (TestSupportsThinkingToggleVisibility, TestTwoStateToggleControl) that drive the actual ui.js functions through Node.js sub-processes, verifying chip visibility and two-way toggle option rendering across all three GLM tiers.
tests/test_reasoning_show_hide.py	Updates test_set_reasoning_effort_rejects_invalid to reflect the new accepted-empty contract; removes the assertion that set_reasoning_effort('') raises ValueError and adds a positive test that it completes without error.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["Model + Provider ID"] --> B["_resolve_provider_alias()"]
    B --> C{"provider == 'zai'?"}
    C -- No --> D["Other provider rules\n(OpenAI ceiling, Gemini, Anthropic)"]
    C -- Yes --> E{"'glm' in bare id?"}
    E -- No --> D
    E -- Yes --> F{"bare.startswith('glm-4.7')?"}
    F -- Yes --> G["'forced'\nNeither toggle nor ladder"]
    F -- No --> H["re.search version\nmajor, minor"]
    H --> I{"(major,minor) >= (5,2)?"}
    I -- Yes --> J["'effort'\nFull ladder + toggle\nGLM-5.2+"]
    I -- No --> K{"(major,minor) >= (4,5)?"}
    K -- Yes --> L["'thinking'\nToggle only, no ladder\nGLM-4.5-5.1"]
    K -- No --> M["None\nNo thinking support\nGLM-4 and below"]
    J --> N["resolve_model_reasoning_efforts\n-> [minimal..max]"]
    L --> O["resolve_model_reasoning_efforts\n-> []"]
    G --> P["resolve_model_reasoning_efforts\n-> [] (forced exit)"]
    N --> Q["get_reasoning_status\nsupports_thinking_toggle: true"]
    O --> R["get_reasoning_status\nsupports_thinking_toggle: true"]
    P --> S["get_reasoning_status\nsupports_thinking_toggle: false"]
    Q --> T["UI: Full effort dropdown"]
    R --> U["UI: Default + None only"]
    S --> V["UI: Chip hidden"]

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%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A["Model + Provider ID"] --> B["_resolve_provider_alias()"]
    B --> C{"provider == 'zai'?"}
    C -- No --> D["Other provider rules\n(OpenAI ceiling, Gemini, Anthropic)"]
    C -- Yes --> E{"'glm' in bare id?"}
    E -- No --> D
    E -- Yes --> F{"bare.startswith('glm-4.7')?"}
    F -- Yes --> G["'forced'\nNeither toggle nor ladder"]
    F -- No --> H["re.search version\nmajor, minor"]
    H --> I{"(major,minor) >= (5,2)?"}
    I -- Yes --> J["'effort'\nFull ladder + toggle\nGLM-5.2+"]
    I -- No --> K{"(major,minor) >= (4,5)?"}
    K -- Yes --> L["'thinking'\nToggle only, no ladder\nGLM-4.5-5.1"]
    K -- No --> M["None\nNo thinking support\nGLM-4 and below"]
    J --> N["resolve_model_reasoning_efforts\n-> [minimal..max]"]
    L --> O["resolve_model_reasoning_efforts\n-> []"]
    G --> P["resolve_model_reasoning_efforts\n-> [] (forced exit)"]
    N --> Q["get_reasoning_status\nsupports_thinking_toggle: true"]
    O --> R["get_reasoning_status\nsupports_thinking_toggle: true"]
    P --> S["get_reasoning_status\nsupports_thinking_toggle: false"]
    Q --> T["UI: Full effort dropdown"]
    R --> U["UI: Default + None only"]
    S --> V["UI: Chip hidden"]

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_{Reviews (4): Last reviewed commit: "fix(reasoning): make ZAI thinking toggle..." | Re-trigger Greptile}

[rh-id]

Thanks @greptile-apps[bot] for the review — both P2 findings were real and are addressed in 48fdac7.

1. Vacuous test assertion — fixed

test_glm_5_2_preserves_none_sentinel had an or fallback (set(efforts) == {6 levels}) that was always true given the preceding test, so the assertion could never fail. You were right that the intent ("none must survive filtering") was never actually enforced.

Rewrote to inject none via the raw source by mocking _resolve_model_reasoning_efforts_impl to return ["none", "minimal", ..., "max"], then asserting "none" in efforts. This genuinely exercises the preservation branch in resolve_model_reasoning_efforts (which strips none before calling _filter_reasoning_efforts_for_provider, then re-attaches it from its original position). The test now fails if that re-attachment ever breaks for GLM-5.2.

2. Coercion gap for non-max stored levels — fixed

This was the more important catch. My original PR claimed "UI options and coercion now agree," but that only held for max. A stored high/medium/low/xhigh/minimal for glm-5.1/glm-4.5/glm-4.5-flash/glm-5/glm-5-turbo/glm-4.7 on native zai was forwarded to Z.AI unchanged (silently ignored there) — because the existing if ceiling and raw not in ceiling guard at line 3935 treats an empty ceiling as "no rule," preserving the configured effort verbatim per #3505.

Root cause: my ZAI gate returns [] to mean "known-empty" (this model is documented as not supporting reasoning_effort at all), but the coercion path treated every [] as "ambiguous/unknown, preserve verbatim." The two semantics collided.

Fix: extracted the ZAI decision into a shared helper _zai_glm_reasoning_efforts_supported(model_id, provider_id) -> bool | None — returns True (GLM-5.2+), False (pre-5.2 / forced-thinking GLM-4.7), or None (not a native-zai GLM case, defer to other rules). Both _filter_reasoning_efforts_for_provider and coerce_reasoning_effort_for_model consume it. In coercion, a known-False result now returns "" (send no reasoning_effort field) before the #3505 preserve-verbatim path runs. This is the "fix the class, not the instance" approach — one decision function, two consumers, can't drift.

#3505 behavior preserved: a genuinely-unknown model on a non-zai provider (e.g. some-brand-new-model-9999 on custom:myrouter) still preserves the configured effort verbatim — the ZAI gate returns None for it and the original ambiguous-empty path runs unchanged. New regression test test_coerce_unchanged_for_unknown_non_zai_models pins this.

Regression gate (per guideline #6)

10 new coercion tests fail before the coercion fix, all pass after (verified via stash):

• All 6 levels (max/xhigh/high/medium/low/minimal) coerce to "" for each pre-5.2 GLM + glm-4.7 × all 4 aliases (glm/z-ai/z.ai/zhipu)
• GLM-5.2 preserves all 6 levels verbatim
• Unknown model on custom: provider still preserves verbatim (Coerce reasoning effort to model/provider-supported levels #3505 guard)

Suite total: 34 tests (was 24), all green. 132/132 pass across the ZAI + neighboring reasoning/catalog suites. No new lint errors.

The invariant now fully holds end-to-end: the UI offers no reasoning_effort options for pre-5.2 GLM models, AND the coercion sends no reasoning_effort field for any stored level on those models.

[nesquena-hermes]

Great catch on the real problem — the WebUI genuinely does over-advertise the reasoning_effort ladder for sub-5.2 GLM models, and your version parsing is solid (the gate verified canonical 4.5–6.x, casing, namespaces, provider prefixes, and GLM-5.2 none all resolve correctly). But the gate reproduced one SILENT regression the current shape introduces, so I'm bouncing with the fix — it's a small scoping change.

SILENT — sub-5.2 GLM users lose the working thinking on/off control — api/config.py:3471 → static/ui.js:4932-4938

Per your own premise: thinking: {enabled|disabled} is supported by GLM-4.5+, only the reasoning_effort ladder is 5.2+. But gating by returning [] for the effort list makes the frontend hide the entire reasoning chip — including the none/off action — because static/ui.js:4932-4938 treats an empty supported_efforts as "no reasoning control at all." So GLM-4.5/4.6/5.0/5.1 users (who today CAN toggle thinking on/off) would lose that control entirely. That's a functional regression for 4 GLM versions, not the intended "hide only the effort levels."

Fix: separate thinking-toggle capability from supported_efforts.

• Keep the effort ladder empty below GLM-5.2 (your gate is correct there).
• But retain a binary-thinking capability for GLM-4.5+ except forced-thinking GLM-4.7 (4.7 forces thinking on — no toggle), so the composer still renders an operable On/Default + None control when the effort ladder is empty.
• In static/ui.js:4932, render the explicit On/None actions when supported_efforts is empty but binary-thinking is supported, instead of hiding the whole chip.

GLM-4.7 (forced thinking) correctly shows neither an off toggle nor an effort ladder. GLM-5.2+ keeps the full ladder + none. Sub-5.2-but-4.5+ keeps On/None only.

Add a test asserting: GLM-4.6 → no effort ladder BUT thinking On/None still available; GLM-4.7 → forced (no off); GLM-5.2 → full ladder + none. Everything else (non-GLM gating, custom/aggregator routing, 127 focused tests) verified unchanged — this is the only blocker. Re-push and I'll re-gate.

[nesquena-hermes]

Version-parsing solid, but returning [] efforts for sub-5.2 GLM hides the whole reasoning chip incl the thinking on/off toggle that GLM-4.5+ DOES support. Fix: separate thinking-toggle capability from supported_efforts (keep ladder empty <5.2 but retain On/None for 4.5+ except forced-thinking 4.7). Fix-spec posted. Re-gate on re-push.

[rh-id]

Great catch — this was a real silent regression I had missed. The round-1 gate returned [] for the effort ladder on sub-5.2 GLM, which static/ui.js:4932 interprets as "no reasoning control at all," so GLM-4.5/4.6/5.0/5.1 users lost the working thinking on/off toggle they had before. Fixed in a30b907 exactly along the scoping you prescribed.

Fix — decoupled thinking-toggle capability from the effort ladder

Backend (api/config.py)

Refactored the ZAI gate into a single three-tier classifier _zai_glm_classification(model_id, provider_id) -> "effort" | "thinking" | "forced" | None:

• "effort" — GLM-5.2+ (full ladder + thinking toggle)
• "thinking" — GLM-4.5 up to but not including 5.2 (toggle only, no ladder)
• "forced" — GLM-4.7 family (forced thinking, neither)
• None — non-zai provider, non-GLM model, or pre-4.5 GLM (defer)

This is now the single source of truth. _zai_glm_reasoning_efforts_supported (used by coercion) becomes a thin wrapper returning cls == "effort". A new _zai_glm_thinking_toggle_supported returns cls in {"effort", "thinking"}.

get_reasoning_status gains a supports_thinking_toggle field:

supports_thinking_toggle = bool(supported_efforts) or (zai_thinking is True)

For non-zai providers, zai_thinking is None, so this collapses to bool(supported_efforts) — their chip-visibility behavior is byte-identical to before. The new field only diverges for the native-zai middle tier.

Frontend (static/ui.js)

• New _currentReasoningToggleSupported state var (default undefined, treated as true so legacy responses without the field do not newly hide the chip).
• _applyReasoningChip: const supports = hasEffortLadder || toggleSupported. Empty efforts + toggle=true keeps the chip visible (the existing _applyReasoningOptions already shows only the none option when the ladder is empty, so the user gets the operable On/None control you described). Empty efforts + toggle=false (GLM-4.7 forced) hides the chip.
• Profile-transition and fetch-failure resets now pass supports_thinking_toggle: false alongside the empty efforts, so the chip hides during the unknown-state window (matches the prior reset contract).

Result by tier

Model	effort ladder	thinking toggle	chip
glm-5.2 / glm-5.3 / glm-6	full 6 levels	yes	full dropdown
glm-5.1 / glm-5 / glm-5-turbo / glm-4.6 / glm-4.5 / glm-4.5-flash / glm-4.5-air	empty	yes	On/None only (the previously-working control, preserved)
glm-4.7 / glm-4.7-air	empty	no	hidden (forced thinking)

Tests (30 new)

• _zai_glm_classification parametrized across all three tiers + aliases (glm/z-ai/z.ai/zhipu resolve through the same gate) + non-zai/non-GLM defer cases.
• get_reasoning_status supports_thinking_toggle per tier — including the exact scenarios you asked for: GLM-4.6 → no ladder BUT thinking On/None available; GLM-4.7 → forced (no off); GLM-5.2 → full ladder + none. Plus GLM-4.5-flash/5/5.1/5-turbo, all four aliases, and a regression guard that non-zai providers default to bool(supported_efforts) (no spurious toggle when ZAI gate doesn't fire).
• Frontend _applyReasoningChip behavior via the existing node driver (extended to pass meta): empty efforts + toggle=true stays visible, toggle=false hides, effort ladder alone is sufficient regardless of toggle flag, absent field keeps prior behavior.

Regression gate

The three-tier classification is structurally new in this round (the helper, the field, and the frontend flag did not exist before), so the per-tier status assertions cannot pass without the fix. The pre-existing chip suite (test_reasoning_chip_js_behaviour, test_reasoning_chip_btw_fixes, test_issue1103_reasoning_chip_visibility, test_issue4650_reasoning_chip_no_storm) all still pass — 190 passed, 1 skipped across the full reasoning + chip surface.

Re-push is in; ready for re-gate.

[nesquena-hermes]

Round-2 re-gate — visibility regression fixed, but the toggle is now one-way

Re-reviewing against my round-1 ask (separate the thinking on/off capability from the effort ladder so returning [] efforts doesn't hide the whole chip for GLM-4.5–5.1). Reading api/config.py at _zai_glm_classification / _zai_glm_thinking_toggle_supported and the static/ui.js chip path at HEAD a30b9079:

The three-tier split is right and the visibility fix lands. get_reasoning_status now emits supports_thinking_toggle (config.py ~4106-4133), and _applyReasoningChip keeps the wrap visible when the ladder is empty but the toggle is live:

const hasEffortLadder=Array.isArray(supportedEfforts)?supportedEfforts.length>0:true;
const supports=hasEffortLadder||toggleSupported;   // ui.js:4941-4943

The node-driven TestSupportsThinkingToggleVisibility cases (empty+toggle → visible, forced-thinking → hidden, absent flag → visible legacy default) pin exactly the contract I asked for. The off-path is also sound end to end: coerce_reasoning_effort_for_model preserves the none sentinel via the early if raw == "none": return "none" (config.py:3985-3986), so thinking-OFF still reaches the wire while effort levels collapse to "".

The residual gap — you can turn thinking OFF but not back ON

For a thinking-toggle model the chip is now visible, but the dropdown is populated by _applyReasoningOptions(supportedEfforts) with supportedEfforts=[] (ui.js:4951). That function only ever un-hides none when the set is empty:

dd.querySelectorAll('.reasoning-option').forEach(function(opt){
  const effort=opt.dataset.effort;
  if(effort==='none'){ opt.style.display=''; return; }   // ui.js:4896-4899
  if(!supported.size){ opt.style.display='none'; return; } // everything else hidden
  ...
});

The dropdown HTML has no selectable "Default"/"On" entry — only none/minimal/low/medium/high/xhigh/max (index.html:757-763). So for GLM-4.6 the dropdown renders a single item, "None". A user can click it to disable thinking, but once off there's no option to re-enable (the "on" state is empty-effort "", which isn't a clickable option). The "On/None control" is effectively None-only.

Recommendation

Give thinking-toggle models a real two-state control. Minimal approach: when supports_thinking_toggle && supported_efforts is empty, have _applyReasoningOptions also surface an explicit "On"/"Default" option (data-effort "") so the dropdown offers On + None. Sketch at ui.js:4892:

function _applyReasoningOptions(supportedEfforts, toggleOnly){
  // toggleOnly (empty ladder + thinking toggle): show only Default(on) + None
  ...
}

Plus a data-effort="" "Default (on)" .reasoning-option in index.html (POST /api/reasoning with effort:'' already round-trips to provider-default). A behavioural test asserting the dropdown exposes both an "on" and a "none" option for {supported_efforts:[], supports_thinking_toggle:true} would lock it in — the current TestSupportsThinkingToggleVisibility only checks wrap visibility, not that the toggle is operable in both directions.

Everything else here is ready to merge once the re-enable path exists. Nice work isolating the three tiers cleanly.

[nesquena-hermes]

Good progress — the whole-chip-hidden regression is closed (the tri-state forced/thinking/effort now correctly gives GLM-5.2+ the full ladder, and version parsing across 4.5–6.x / casing / namespaces / provider aliases / non-GLM all re-verified clean). But the round-2 reproduction against the actual renderer found two SILENT gaps in the toggle-only path — bouncing with both, then this ships.

SILENT — the thinking toggle is ONE-WAY for GLM-4.5/4.6/5.0/5.1 — static/ui.js:4902

Verified with the real renderer: both before AND after selecting None, the only visible dropdown option is none — there's no On/Default item (static/index.html:757 has no such option, and api/config.py:4247 rejects an empty effort). So a toggle-only GLM user can turn thinking OFF but can never turn it back ON. That's worse than the original bug in a sense (a stuck-off control).

Fix: add a nonempty On/Default action that clears agent.reasoning_effort (backend must accept the clear, not reject empty), render On + None for toggle-only models, and test the off→on→off round trip.

SILENT — GLM-4.7 not consistently forced when none is already stored — api/config.py:3984 (+ :3857)

Verified: when GLM-4.7 has reasoning_effort: none already configured, status + coercion preserve none while reporting supports_thinking_toggle:false → streaming then constructs disabled reasoning, even though 4.7 forces thinking ON and isn't configurable. Separately, api/config.py:3857 reattaches an explicit none → supported_efforts=['none'] for GLM-4.7 (should be empty/forced).

Fix: check the forced classification BEFORE preserving none (coerce a stored none to default for forced GLM-4.7), and never reattach none to a forced model's supported options.

Everything else re-verified clean (canonical tiers, casing, namespaces, aliases, custom-provider deferral, non-GLM matched master; 79 changed + 62 neighboring tests + node --check pass). Re-push these two + the off→on round-trip test + a forced-4.7-with-stored-none test and I'll re-gate — you're close, this is the last mile on the toggle semantics.

[nesquena-hermes]

Round 2: whole-chip-hidden regression closed + version-parse re-verified clean, but 2 SILENT gaps remain: (1) ui.js:4902 thinking is ONE-WAY for 4.5-5.1 (only 'none' option, no On/Default — can't re-enable; backend rejects empty effort); (2) config.py:3984/3857 GLM-4.7 not forced when 'none' already stored (streaming builds disabled reasoning + supported_efforts=['none']). Fix-spec posted.

[rh-id]

Both SILENT gaps closed in 0855e22, plus a click-handler sibling I found while auditing the toggle path end-to-end.

Gap #1 — One-way toggle fixed (the thinking tier can now re-enable)

Three coordinated changes so GLM-4.5/4.6/5.0/5.1 get a real two-state Default+None control:

Backend (set_reasoning_effort): empty effort is now accepted as "clear the override" — it removes agent.reasoning_effort from config.yaml so the provider default (thinking on) takes effect. Invalid values still raise ValueError. The /api/reasoning POST handler already passed "" through (if effort is not None:), so no route change was needed.

Frontend (static/index.html + _applyReasoningOptions): added a Default option (data-effort="") to the dropdown, and _applyReasoningOptions now always shows both none and "" (alongside the effort ladder). A thinking-tier model (empty ladder + toggle=true) therefore renders Default + None — the operable two-state control you described.

Click handler sibling (ui.js:5106): the existing click guard was if(effort) — falsy for the empty string, so the Default button would have been silently dead even after the HTML/backend changes. Changed to if(opt) (option presence) so data-effort="" clicks actually POST. Without this the round trip would still be one-way off-only despite the other two fixes.

Gap #2 — GLM-4.7 forced + stored none fixed

Two coordinated changes so a forced-thinking model never offers or sends none:

Coercion (coerce_reasoning_effort_for_model): added a forced-tier check BEFORE the generic if raw == "none": return "none" early-return. A stored none now coerces to "" (default = thinking on) for GLM-4.7, so streaming no longer builds disabled reasoning for a forced-thinking model.

Resolver (resolve_model_reasoning_efforts): returns [] early for forced-tier models, skipping the none reattachment block. So even when the raw capability source (provider config / models.dev) lists none, GLM-4.7's supported_efforts stays [] — no none leak to the UI.

End-to-end trace (verified empirically, all models with stored none)

Model	coerce(none)	supported_efforts	status reasoning_effort	toggle
glm-5.2	none	full ladder	none	true
glm-4.6	none	[] (or ["none"] if raw source lists it)	none	true
glm-4.7	""	[]	"" (default = on)	false
glm-4.7-air	""	[]	""	false

Tests (17 new + 1 updated)

• Gap Hermes Web UI — Sprints 11-14: multi-provider models, settings, sessi… #2 (6 new): coerce('none', glm-4.7) → '' × glm-4.7 + glm-4.7-air; regression guard that glm-5.2/4.6/5.1 still accept none; resolver does NOT reattach none for forced but DOES for thinking-tier; end-to-end get_reasoning_status for forced + stored none.
• Gap Portability #1 backend (3 new + 1 updated): set('') clears the key without raising; set('garbage') still raises; all 7 valid levels still save. Updated test_reasoning_show_hide.test_set_reasoning_effort_rejects_invalid to reflect the new contract (empty accepted, garbage rejected).
• Gap Portability #1 frontend (3 new): node-driver tests asserting the dropdown exposes both Default and None for thinking-tier (two-state), Default+None+ladder for effort-tier, and the off→on→off round trip keeps both options visible at every step.

Regression gate (per guideline #6)

• Gap Hermes Web UI — Sprints 11-14: multi-provider models, settings, sessi… #2 coerce: 3 tests fail without the forced-tier check (coerce_stored_none_to_empty_for_forced_glm[glm-4.7/-air] + get_reasoning_status_forced_glm_with_stored_none_reports_default).
• Gap Portability #1 backend: test_set_reasoning_effort_accepts_empty_as_clear fails with ValueError: effort is required without the empty-acceptance change.
• Gap Portability #1 frontend: the Default option and the if(opt) click guard are structurally new — the two-state dropdown tests cannot pass without them.

219 passed, 1 pre-existing skip across the full reasoning + chip + config-cache surface (test_zai_reasoning_effort_gating, test_reasoning_chip_js_behaviour, test_reasoning_chip_btw_fixes, test_issue1103_reasoning_chip_visibility, test_issue4650_reasoning_chip_no_storm, test_reasoning_effort_model_capabilities, test_reasoning_show_hide, test_models_dev_reasoning, test_issue3750_lmstudio_probe_auth, test_issue4650_yaml_config_cache, test_issue3958_reasoning_post_session_context). ui.js syntax valid (node --check). No new lint errors.

Out of scope (noted, not changed)

The CLI /reasoning slash command (static/commands.js) does not expose a default alias — its EFFORTS list is none/minimal/low/medium/high/xhigh/max. The status display already maps empty effort to 'default', so the concept exists CLI-side. Adding a /reasoning default alias would give the CLI parity with the new WebUI Default button, but it's a separate enhancement and outside this bug fix's scope.

Re-push is in; ready for re-gate.

[nesquena-hermes]

Shipped in exp-v0.52.105. Thanks @rh-id — great persistence through 4 gate rounds! 🎉 The final gate verified the full off→on→off toggle round trip for GLM-4.5/4.6/5.0/5.1, GLM-4.7 forced-thinking even with a stored none, GLM-5.2+ full ladder intact, and all 3 surfaces agreeing across tiers/aliases/namespaces.