An effort the model had never heard of

Reported from a live instance, on Bonsai:

  Jinja Exception: Unexpected reasoning effort high. Supported types are
  xhigh (default), medium, and low.

Effort goes out two ways because no single field works, and the second --
chat_template_kwargs -- is not a parameter the server interprets. It is
rendered into the model's own chat template, which does not ignore a value it
does not know: it calls raise_exception, and the request dies before a token.
So a perfectly ordinary option, drawn by this application in its own menu, took
the whole reply with it.

The vocabulary is per model and nobody agrees. gpt-oss takes low/medium/high.
Bonsai takes low/medium/xhigh and refuses high. OpenAI has added minimal, xhigh
and max at different points, and which of them a given model accepts varies
again. One global tuple was going to be wrong for somebody whatever it held.

A model carries its own list now, and the picker, the slash command and the
request builder all read it. A column rather than a key in capabilities_json,
for the reason context_length is one: that dict is rebuilt wholesale from the
submitted checkboxes on every save.

And it corrects itself. A refusal retries the reply once without the effort
rather than losing it -- safe only because the template renders before any
token, so nothing has been emitted, and there is a guard that keeps it that way
-- then narrows the model's list. Bonsai's error states what it does take, so
that is what gets stored.

Note the parser bug, because it is a good one: "high" is a substring of
"xhigh", so reading the advertised list by substring learned `high` from a
sentence explaining that `high` is the problem. Whole words now, with a test
named after it.

/effort reads its levels off the picker instead of a second copy of the list
kept in the browser.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/lembas/web/static/js/commands.js

@@ -271,8 +271,21 @@
 
   /* --- Reasoning effort ---------------------------------------------------
      The command drives the same select the composer shows, so there is one
-     piece of state and the control updates itself when the command is used. */
-  var EFFORTS = ["low", "medium", "high"];
+     piece of state and the control updates itself when the command is used.
+
+     Which efforts exist is read off that select's own options rather than
+     kept here. It used to be a second copy of `["low","medium","high"]`, which
+     was wrong the moment the vocabulary became per model: a Bonsai takes
+     `xhigh` and no `high`, so the list the server rendered and the list this
+     file believed in disagreed -- and the one that decides what `/effort xhigh`
+     does was this one. The select is the table; nothing else should hold it. */
+  function efforts() {
+    var select = el("[data-effort]");
+    if (!select) return [];
+    return Array.prototype.map
+      .call(select.options, function (option) { return option.value; })
+      .filter(function (value) { return value !== "off"; });
+  }
 
   function setEffort(rest) {
     var select = el("[data-effort]");
@@ -283,12 +296,14 @@
         "error"
       );
     }
+    var available = efforts();
+    var listed = available.join(", ");
     var wanted = (rest || "").trim().toLowerCase();
     if (!wanted) {
       return note(
-        EFFORTS.indexOf(select.value) === -1
-          ? "No effort is being sent. Try low, medium or high."
-          : "Effort is " + select.value + ". /effort low, medium, high, or off."
+        available.indexOf(select.value) === -1
+          ? "No effort is being sent. Try " + listed + "."
+          : "Effort is " + select.value + ". /effort " + listed + ", or off."
       );
     }
     /* "off" is the option's real value, not an empty string: the new-chat form
@@ -296,8 +311,11 @@
        sentinel and this has to match it. "default" and "none" still work,
        because somebody's fingers will type them. */
     if (wanted === "default" || wanted === "none") wanted = "off";
-    else if (wanted !== "off" && EFFORTS.indexOf(wanted) === -1) {
-      return note("“" + wanted + "” is not an effort. Try low, medium, high or off.", "error");
+    else if (wanted !== "off" && available.indexOf(wanted) === -1) {
+      return note(
+        "“" + wanted + "” is not an effort this model takes. Try " + listed + " or off.",
+        "error"
+      );
     }
     select.value = wanted;
     select.dispatchEvent(new Event("change", { bubbles: true }));

src/lembas/web/templates/admin/model_detail.html

@@ -104,11 +104,39 @@
       </p>
     </div>
 
+    <div class="field">
+      <span class="field__label">Reasoning efforts this model accepts</span>
+      <div class="btn-row">
+        {% for value in efforts %}
+        <label class="checkbox">
+          <input type="checkbox" name="reasoning_efforts" value="{{ value }}"
+                 {{ 'checked' if value in model_efforts }}>
+          <span class="mono">{{ value }}</span>
+        </label>
+        {% endfor %}
+      </div>
+      <p class="field__hint">
+        The vocabulary is <strong>not the same for every model</strong>, and
+        sending one a model does not know is not ignored — it is rendered into
+        the model's chat template, which raises and fails the whole reply.
+        gpt-oss takes <span class="mono">low/medium/high</span>; Bonsai takes
+        <span class="mono">low/medium/xhigh</span> and refuses
+        <span class="mono">high</span>; OpenAI has added
+        <span class="mono">minimal</span>, <span class="mono">xhigh</span> and
+        <span class="mono">max</span> at various points.
+        <br>
+        Tick none and the common three are offered, which is right for almost
+        everything. If an endpoint ever refuses one anyway, that reply is
+        retried without it and this list corrects itself — so this is worth
+        setting by hand only to save that one round trip.
+      </p>
+    </div>
+
     <div class="field">
       <label class="field__label" for="default-effort">Default reasoning effort</label>
       <select class="select" id="default-effort" name="default_effort">
         <option value="">None — send nothing</option>
-        {% for value in efforts %}
+        {% for value in model_efforts %}
         <option value="{{ value }}"
                 {{ 'selected' if model.params_json.get('reasoning_effort') == value }}>
           {{ value }}