feat(scan): choose model, reasoning effort and cost limit per scan

README.md

@@ -103,7 +103,7 @@ For the multi-repository case the model clones what is not checked out locally,
 
 **Scan**
 
-Standard or Deep. The whole repository, selected paths, your uncommitted changes, or everything since a branch or commit. Set a time limit if you want one. Two scans can run at once.
+Standard or Deep. The whole repository, selected paths, your uncommitted changes, or everything since a branch or commit. For each scan you can pick the reasoning effort, a cost limit and a time limit. Two scans can run at once.
 
 **Review findings**
 

docs/CONFIG.md

@@ -110,6 +110,10 @@ Tell it the window your provider gives that model, and when to compact:
 
 Use the limit your provider reports for the model (the error message states it), and set the compaction limit to roughly 80% of it. These are native Codex settings, so they also work in `~/.codex/config.toml`, including inside a profile.
 
+## Settings for one scan
+
+The scan review lets you change the reasoning effort, cost limit, time limit and model for that scan only. In chat, ask for it: "scan this on low effort, stop at $5". Anything you leave alone comes from the files above.
+
 ## Time limits
 
 `scan.maxTimeMinutes` sets how long a scan investigates. A Standard scan has no limit by default and treats the value as a target: the model paces itself, and writing the report can run past it. A Deep scan stops discovery at the limit; without one the SDK's own default applies (96 hours). You can also set it for one scan in the scan review.

src/core/scan-plan.ts

@@ -24,6 +24,10 @@ export interface ScanInputs {
   contextFiles?: string[];
   /** Minutes of investigation. Advisory for Standard; a discovery deadline for Deep. */
   maxTimeMinutes?: number;
+  /** For this scan only, instead of the configured model, reasoning effort and cost limit. */
+  model?: string;
+  reasoningEffort?: string;
+  maxCostUsd?: number;
   /** Continue an interrupted Deep scan instead of starting a new one. Other inputs are ignored. */
   resumeRunId?: string;
 }
@@ -79,6 +83,12 @@ function parseInputs(value: unknown): ScanInputs {
     !['undefined', 'string'].includes(typeof data.repository) ||
     !['undefined', 'string'].includes(typeof data.scanPrompt) ||
     !['undefined', 'string'].includes(typeof data.changes) ||
+    !['undefined', 'string'].includes(typeof data.model) ||
+    !['undefined', 'string'].includes(typeof data.reasoningEffort) ||
+    !(
+      data.maxCostUsd === undefined ||
+      (typeof data.maxCostUsd === 'number' && data.maxCostUsd > 0)
+    ) ||
     !strings(data.scopePaths) ||
     !strings(data.contextFiles) ||
     ![undefined, 'standard', 'deep'].includes(data.mode as string) ||
@@ -88,7 +98,7 @@ function parseInputs(value: unknown): ScanInputs {
     )
   )
     throw new SecurityInputError(
-      'Scan inputs are repository, scopePaths, changes, scanPrompt, contextFiles, mode (standard or deep) and maxTimeMinutes.',
+      'Scan inputs are repository, scopePaths, changes, scanPrompt, contextFiles, mode (standard or deep), maxTimeMinutes, model, reasoningEffort and maxCostUsd.',
     );
   if (data.changes && (data.scopePaths as string[] | undefined)?.length)
     throw new SecurityInputError('Scan either paths or changes, not both.');
@@ -215,11 +225,19 @@ export async function prepareScan(
   const scanSettings = {
     ...settings.scan,
     ...(input.maxTimeMinutes ? { maxTimeMinutes: input.maxTimeMinutes } : {}),
+    ...(input.maxCostUsd ? { maxCostUsd: input.maxCostUsd } : {}),
+  };
+  const codex = {
+    ...settings.codex,
+    ...(input.model?.trim() ? { model: input.model.trim() } : {}),
+    ...(input.reasoningEffort?.trim()
+      ? { model_reasoning_effort: input.reasoningEffort.trim() }
+      : {}),
   };
   if (purpose === 'validation') delete scanSettings.maxCostUsd;
   const changes = input.changes?.trim() || undefined;
   const target = await scanTarget({ scopePaths: input.scopePaths, changes });
-  return withSdk(settings.codex, async (client, sdk) => {
+  return withSdk(codex, async (client, sdk) => {
     const preflight = await client.preflight(repository, {
       ...scanSettings,
       auth: settings.auth,
@@ -236,11 +254,11 @@ export async function prepareScan(
       scanPrompt: input.scanPrompt ?? '',
       contextFiles: contextFiles.map((path) => ({ path })),
       settings: {
-        codex: (await routeFrom(sdk, settings.codex, preflight)).route,
+        codex: (await routeFrom(sdk, codex, preflight)).route,
         scan: { ...scanSettings, mode: preflight.mode },
       },
       globalConfigFile: settings.path,
-      sdk: { codexOverrides: settings.codex, auth: settings.auth },
+      sdk: { codexOverrides: codex, auth: settings.auth },
       expiresAt: new Date(Date.now() + 10 * 60_000).toISOString(),
       mock,
       // No undefined members: the host only carries JSON values over RPC.

src/gui/ScanComposer.tsx

@@ -1,7 +1,7 @@
-import { createSignal, Show } from 'solid-js';
+import { createSignal, For, Show } from 'solid-js';
 import { asState } from '../types';
 import type { ScanInputs, ScanPlan } from '../core/scan-plan';
-import { splitPaths, userError } from '../scan-display';
+import { reasoningEfforts, splitPaths, userError } from '../scan-display';
 import { ScanReview } from './ScanReview';
 import type { SecurityPort, SecurityStore } from './store';
 
@@ -41,6 +41,9 @@ export function ScanComposer(props: {
     initial?.contextFiles.map((file) => file.path).join('\n') ?? '',
   );
   const [minutes, setMinutes] = createSignal(initial?.inputs.maxTimeMinutes?.toString() ?? '');
+  const [effort, setEffort] = createSignal(initial?.inputs.reasoningEffort ?? '');
+  const [cost, setCost] = createSignal(initial?.inputs.maxCostUsd?.toString() ?? '');
+  const [model, setModel] = createSignal(initial?.inputs.model ?? '');
   const [preview, setPreview] = createSignal<ScanPlan | undefined>(
     props.edit ? undefined : initial,
   );
@@ -73,6 +76,9 @@ export function ScanComposer(props: {
         contextFiles: splitPaths(documents()),
         ...(mode() !== 'default' ? { mode: mode() as 'standard' | 'deep' } : {}),
         ...(Number(minutes()) > 0 ? { maxTimeMinutes: Number(minutes()) } : {}),
+        ...(effort() ? { reasoningEffort: effort() } : {}),
+        ...(Number(cost()) > 0 ? { maxCostUsd: Number(cost()) } : {}),
+        ...(model().trim() ? { model: model().trim() } : {}),
       };
       const next = asState(await props.port.prepare(input));
       if (!next.plan) throw new Error('The server did not return a scan preview.');
@@ -141,6 +147,33 @@ export function ScanComposer(props: {
                 </select>
                 <span class="gs-help">Deep takes longer and costs more.</span>
               </label>
+              <label>
+                Reasoning effort
+                <select
+                  value={effort()}
+                  onChange={(e) => setEffort(e.currentTarget.value)}
+                  aria-label="Reasoning effort"
+                >
+                  <option value="">Default from settings</option>
+                  <For each={reasoningEfforts}>
+                    {(level) => <option value={level}>{level}</option>}
+                  </For>
+                </select>
+                <span class="gs-help">Lower is faster and cheaper; higher looks harder.</span>
+              </label>
+              <label>
+                Cost limit <span class="gs-muted">US dollars, optional</span>
+                <input
+                  type="number"
+                  min="0.01"
+                  step="any"
+                  value={cost()}
+                  onInput={(e) => setCost(e.currentTarget.value)}
+                  placeholder="Default from settings"
+                  aria-label="Cost limit in US dollars"
+                />
+                <span class="gs-help">Stops the scan when its estimated cost passes this.</span>
+              </label>
               <label>
                 Time limit <span class="gs-muted">minutes, optional</span>
                 <input
@@ -209,6 +242,20 @@ export function ScanComposer(props: {
               <Show when={scope() === 'uncommitted' || scope() === 'since'}>
                 <p class="gs-help">Change scans run at Standard depth.</p>
               </Show>
+              <details class="gs-disclosure" open={!!model()}>
+                <summary>Model</summary>
+                <label>
+                  Model
+                  <input
+                    value={model()}
+                    onInput={(e) => setModel(e.currentTarget.value)}
+                    placeholder="Default from settings"
+                    aria-label="Model"
+                    spellcheck={false}
+                  />
+                  <span class="gs-help">For this scan only. Your provider must offer it.</span>
+                </label>
+              </details>
               <details class="gs-disclosure">
                 <summary>Context files</summary>
                 <label>

src/rpc.ts

@@ -35,6 +35,21 @@ export const scanInputSchema = {
       description:
         'Minutes to spend investigating. Standard scans have no limit unless this is set, and treat it as a target; Deep scans stop discovery at it.',
     },
+    model: {
+      type: 'string',
+      description: 'Model for this scan only. Omit to use the configured model.',
+    },
+    reasoningEffort: {
+      type: 'string',
+      description:
+        'Reasoning effort for this scan only, such as low, medium, high or xhigh. Lower is faster and cheaper. Omit to use the configured effort.',
+    },
+    maxCostUsd: {
+      type: 'number',
+      exclusiveMinimum: 0,
+      description:
+        'Stop this scan when its estimated cost passes this many US dollars. Omit to use the configured limit, if any.',
+    },
     resumeRunId: {
       type: 'string',
       description:

src/scan-display.ts

@@ -95,6 +95,8 @@ export function timeLimitLabel(scan: { mode?: string; maxTimeMinutes?: number }
   const amount = minutes >= 120 ? `${Math.round(minutes / 6) / 10}h` : `${minutes}m`;
   return scan?.mode === 'deep' ? `${amount} of discovery` : `${amount} target, not a hard stop`;
 }
+/** Reasoning efforts offered in the review. Others can be set in config or by the scan tool. */
+export const reasoningEfforts = ['low', 'medium', 'high', 'xhigh'] as const;
 /** Why a scan cannot be resumed, or '' when it can. */
 export function resumeProblem(run: ScanState) {
   if (run.status !== 'error' && run.status !== 'cancelled')

src/tui/review.tsx

@@ -3,12 +3,12 @@ import type { Plugin } from '@opencode/plugin/tui';
 import { createSignal, For, Show } from 'solid-js';
 import type { ScanInputs, ScanPlan } from '../core/scan-plan';
 import { describeInferenceRoute, describePlan, isAbsoluteLocalDirectory } from '../plan-view';
-import { scopeLabel, timeLimitLabel, userError } from '../scan-display';
+import { reasoningEfforts, scopeLabel, timeLimitLabel, userError } from '../scan-display';
 import type { Colors } from './theme';
 import { costLine, splitList } from './text';
 
 type Depth = 'default' | 'standard' | 'deep';
-type Edit = 'target' | 'scope' | 'focus' | 'context' | 'time';
+type Edit = 'target' | 'scope' | 'focus' | 'context' | 'time' | 'effort' | 'cost' | 'model';
 type Action = 'start' | 'back' | Edit;
 
 const nextDepth: Record<Depth, Depth> = { default: 'standard', standard: 'deep', deep: 'default' };
@@ -191,6 +191,45 @@ async function edit(ctx: Plugin.Context, field: Edit, plan: ScanPlan) {
     if (!(minutes > 0)) throw new Error('Enter the time limit as a number of minutes.');
     return { ...rest, maxTimeMinutes: minutes };
   }
+  if (field === 'effort') {
+    const { reasoningEffort: _previous, ...rest } = inputs;
+    const choice = await ctx.ui.dialog.select<string>({
+      title: 'Reasoning effort',
+      current: inputs.reasoningEffort ?? '',
+      options: [
+        { title: 'Default from settings', value: '' },
+        ...reasoningEfforts.map((level) => ({ title: level, value: level as string })),
+      ],
+    });
+    if (choice === undefined) return;
+    return choice ? { ...rest, reasoningEffort: choice } : rest;
+  }
+  if (field === 'cost') {
+    const value = await ctx.ui.dialog.prompt({
+      title: 'Cost limit',
+      description:
+        'US dollars. The scan stops when its estimated cost passes this. Leave empty for the configured limit.',
+      value: inputs.maxCostUsd?.toString() ?? '',
+      placeholder: '5',
+    });
+    if (value === undefined) return;
+    const { maxCostUsd: _previous, ...rest } = inputs;
+    if (!value.trim()) return rest;
+    const dollars = Number(value);
+    if (!(dollars > 0)) throw new Error('Enter the cost limit as a number of dollars.');
+    return { ...rest, maxCostUsd: dollars };
+  }
+  if (field === 'model') {
+    const value = await ctx.ui.dialog.prompt({
+      title: 'Model',
+      description: 'For this scan only. Leave empty for the configured model.',
+      value: inputs.model ?? '',
+      placeholder: plan.settings.codex.model,
+    });
+    if (value === undefined) return;
+    const { model: _previous, ...rest } = inputs;
+    return value.trim() ? { ...rest, model: value.trim() } : rest;
+  }
   const value = await ctx.ui.dialog.prompt({
     title: 'Context files',
     description: 'Repository-relative docs to include, separated by commas.',
@@ -228,6 +267,9 @@ function Review(props: {
       { bind: 'f', title: 'Change focus', enabled: idle, run: () => props.onAction('focus') },
       { bind: 'c', title: 'Change context', enabled: idle, run: () => props.onAction('context') },
       { bind: 'm', title: 'Change time limit', enabled: idle, run: () => props.onAction('time') },
+      { bind: 'r', title: 'Change reasoning', enabled: idle, run: () => props.onAction('effort') },
+      { bind: 'l', title: 'Change cost limit', enabled: idle, run: () => props.onAction('cost') },
+      { bind: 'o', title: 'Change model', enabled: idle, run: () => props.onAction('model') },
       { bind: 'i', title: 'Toggle settings', run: props.onSettings },
     ],
   }));
@@ -238,6 +280,10 @@ function Review(props: {
     ['Depth', depth()],
     ['Scope', scopeLabel(props.plan)],
     ['Time limit', timeLimitLabel(props.plan.settings.scan)],
+    [
+      'Model',
+      `${props.plan.settings.codex.model} · ${props.plan.settings.codex.reasoningEffort} reasoning`,
+    ],
     ['Focus', props.plan.scanPrompt || '—'],
     ['Context', props.plan.contextFiles.map((file) => file.path).join(', ') || '—'],
     ['Route', describeInferenceRoute(props.plan.settings)],
@@ -278,8 +324,8 @@ function Review(props: {
         <text fg={props.color.muted()}>{describePlan(props.plan)}</text>
       </Show>
       <text fg={props.color.muted()}>
-        y start · t target · d depth · s scope · m time limit · f focus · c context · i settings ·
-        esc back
+        y start · t target · d depth · s scope · r reasoning · l cost limit · m time limit · o model
+        · f focus · c context · i settings · esc back
       </text>
     </box>
   );

tests/scan-plan.test.mjs

@@ -314,3 +314,22 @@ test('a time limit chosen for one scan reaches the SDK settings', async (t) => {
   assert.equal((await prepareScan(root, {})).settings.scan.maxTimeMinutes, undefined);
   await assert.rejects(prepareScan(root, { maxTimeMinutes: 0 }), /maxTimeMinutes/);
 });
+
+test('model, reasoning effort and cost limit can be chosen for one scan', async (t) => {
+  const root = await project(t);
+  const usual = await prepareScan(root, {});
+  const chosen = await prepareScan(root, {
+    model: 'gpt-5.6-terra',
+    reasoningEffort: 'low',
+    maxCostUsd: 2,
+  });
+  assert.equal(chosen.settings.codex.model, 'gpt-5.6-terra');
+  assert.equal(chosen.settings.codex.reasoningEffort, 'low');
+  assert.equal(chosen.settings.scan.maxCostUsd, 2);
+  assert.equal(chosen.sdk.codexOverrides.model_reasoning_effort, 'low');
+  // Kept in the inputs, so running the scan again or editing it carries them over.
+  assert.equal(chosen.inputs.reasoningEffort, 'low');
+  assert.notEqual(usual.settings.codex.reasoningEffort, 'low');
+  assert.equal(usual.settings.scan.maxCostUsd, undefined);
+  await assert.rejects(prepareScan(root, { maxCostUsd: 0 }), /maxCostUsd/);
+});