diff --git a/apps/server/src/orchestration-v2/Adapters/AntigravityAdapterV2.ts b/apps/server/src/orchestration-v2/Adapters/AntigravityAdapterV2.ts
index 1490140c1e6e2..8cb9e8993ce17 100644
--- a/apps/server/src/orchestration-v2/Adapters/AntigravityAdapterV2.ts
+++ b/apps/server/src/orchestration-v2/Adapters/AntigravityAdapterV2.ts
@@ -73,6 +73,7 @@ const AntigravityProviderCapabilitiesV2 = {
 export interface AntigravityAdapterV2Options {
   readonly instanceId: ProviderInstanceId;
   readonly selfInvocation: SelfInvocation;
+  readonly fileLinkInstructions?: string | undefined;
   readonly makeRuntime: (
     input: Omit<AntigravityAcpRuntimeInput, "spawn" | "childProcessSpawner">,
   ) => Effect.Effect<
@@ -300,6 +301,7 @@ export const makeAntigravityAdapterV2 = Effect.fn("makeAntigravityAdapterV2")(fu
     instanceId: options.instanceId,
     flavor: makeAntigravityAcpAdapterFlavor({ ...options, ...services }),
     selfInvocation: options.selfInvocation,
+    fileLinkInstructions: options.fileLinkInstructions,
     ...(options.nativeLogging === undefined ? {} : { nativeLogging: options.nativeLogging }),
     ...(options.continuationRequests === undefined
       ? {}
diff --git a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts
index 7b63b7efc0b65..ac7d710dd5d4f 100644
--- a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts
+++ b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts
@@ -1887,7 +1887,10 @@ export function makeClaudeQueryOptions(input: {
       type: "preset" as const,
       preset: "claude_code" as const,
       append: [
-        buildRuntimeInstructions({ harness: "Claude Code" }) +
+        buildRuntimeInstructions({
+          harness: "Claude Code",
+          fileLinkInstructions: input.settings?.fileLinkInstructions,
+        }) +
           (input.mcpServers === undefined
             ? ""
             : T3_CODE_ORCHESTRATION_INSTRUCTIONS +
diff --git a/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts b/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts
index 038266ba93426..4c817ce1ee8ae 100644
--- a/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts
+++ b/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts
@@ -766,6 +766,7 @@ export const buildCodexTurnStartParams = Effect.fn("CodexAdapterV2.buildCodexTur
     readonly codexInput: ReadonlyArray<CodexSchema.V2TurnStartParams__UserInput>;
     readonly runtimePolicy: ProviderAdapter.ProviderAdapterV2RuntimePolicy;
     readonly modelSelection: ModelSelection;
+    readonly fileLinkInstructions?: string | undefined;
     readonly hasT3Mcp?: boolean;
     readonly browserToolsAvailable?: boolean;
     readonly deviceToolsAvailable?: boolean;
@@ -801,7 +802,11 @@ export const buildCodexTurnStartParams = Effect.fn("CodexAdapterV2.buildCodexTur
     const t3Context =
       input.hasT3Mcp === true
         ? buildCodexAdditionalContext(
-            { model: input.modelSelection.model, reasoningEffort: effort ?? undefined },
+            {
+              model: input.modelSelection.model,
+              reasoningEffort: effort ?? undefined,
+              fileLinkInstructions: input.fileLinkInstructions,
+            },
             {
               browser: input.browserToolsAvailable ?? true,
               device: input.deviceToolsAvailable ?? false,
@@ -6899,6 +6904,7 @@ export const makeCodexAdapterV2 = Effect.fn("makeCodexAdapterV2")(function* (
               codexInput,
               runtimePolicy: turnInput.runtimePolicy,
               modelSelection: turnInput.modelSelection,
+              fileLinkInstructions: adapterOptions.settings.fileLinkInstructions,
               hasT3Mcp: mcpSession !== undefined,
               browserToolsAvailable: mcpSession?.browserToolsAvailable ?? true,
               deviceToolsAvailable: mcpSession?.capabilities?.has("device") ?? false,
diff --git a/apps/server/src/provider/CodexDeveloperInstructions.test.ts b/apps/server/src/provider/CodexDeveloperInstructions.test.ts
index 5f4a28e886b6a..2e71082ee097e 100644
--- a/apps/server/src/provider/CodexDeveloperInstructions.test.ts
+++ b/apps/server/src/provider/CodexDeveloperInstructions.test.ts
@@ -1,5 +1,6 @@
 import * as NodeAssert from "node:assert/strict";
 
+import { FILE_LINK_INSTRUCTIONS_MAX_LENGTH } from "@t3tools/contracts";
 import { T3_CODE_DEVICE_TOOL_INSTRUCTIONS } from "@t3tools/provider-core/server/orchestrationInstructions";
 import { describe, it } from "vite-plus/test";
 
@@ -11,6 +12,12 @@ import {
 describe("buildCodexAdditionalContext", () => {
   describe.each([
     { model: "custom-model", modelName: "Custom 🦊 Model", reasoningEffort: "xhigh" },
+    {
+      model: "custom-model-longest-file-link-instructions",
+      modelName: "Custom 🦊 Model",
+      reasoningEffort: "xhigh",
+      fileLinkInstructions: "界".repeat(FILE_LINK_INSTRUCTIONS_MAX_LENGTH),
+    },
   ])("with runtime $model", (runtime) => {
     it.each([undefined, { browser: true, device: true }])(
       "keeps every entry within Codex's per-entry cap with tools %j",
diff --git a/apps/server/src/provider/CodexDeveloperInstructions.ts b/apps/server/src/provider/CodexDeveloperInstructions.ts
index cbfd514eb11a6..e50774150faba 100644
--- a/apps/server/src/provider/CodexDeveloperInstructions.ts
+++ b/apps/server/src/provider/CodexDeveloperInstructions.ts
@@ -35,6 +35,7 @@ export interface CodexRuntimeInfo {
   readonly model: string;
   readonly modelName?: string | undefined;
   readonly reasoningEffort?: string | undefined;
+  readonly fileLinkInstructions?: string | undefined;
 }
 
 /** Keep this outside collaboration mode; model-catalog mode text overrides client developer_instructions. */
diff --git a/apps/server/src/provider/Drivers/AntigravityDriver.ts b/apps/server/src/provider/Drivers/AntigravityDriver.ts
index 7bb1f25b67ce7..c6923a08c1bde 100644
--- a/apps/server/src/provider/Drivers/AntigravityDriver.ts
+++ b/apps/server/src/provider/Drivers/AntigravityDriver.ts
@@ -459,6 +459,7 @@ export const AntigravityDriver: ProviderDriver<
     const orchestrationAdapter = yield* makeAntigravityAdapterV2({
       instanceId,
       selfInvocation,
+      fileLinkInstructions: settings.fileLinkInstructions,
       makeRuntime,
       withProcess: authFlow.withProcess,
       defaultModel,
diff --git a/apps/server/src/provider/ProviderInstanceRegistry.test.ts b/apps/server/src/provider/ProviderInstanceRegistry.test.ts
index e998332d3e92f..959838d825654 100644
--- a/apps/server/src/provider/ProviderInstanceRegistry.test.ts
+++ b/apps/server/src/provider/ProviderInstanceRegistry.test.ts
@@ -12,6 +12,7 @@ import {
   EnvironmentId,
   type ClaudeSettings,
   type CodexSettings,
+  DEFAULT_FILE_LINK_INSTRUCTIONS,
   ProviderDriverKind,
   type ProviderInstanceConfigMap,
   type ResolvedProviderInstanceEnvironment,
@@ -100,6 +101,7 @@ const makeCodexConfig = (overrides: Partial<CodexSettings>): CodexSettings => ({
   homePath: "",
   shadowHomePath: "",
   launchArgs: "",
+  fileLinkInstructions: DEFAULT_FILE_LINK_INSTRUCTIONS,
   customModels: [],
   ...overrides,
 });
@@ -110,6 +112,7 @@ const makeClaudeConfig = (overrides: Partial<ClaudeSettings>): ClaudeSettings =>
   homePath: "",
   customModels: [],
   launchArgs: "",
+  fileLinkInstructions: DEFAULT_FILE_LINK_INSTRUCTIONS,
   autoCompactWindow: "",
   idleCompaction: "default",
   ...overrides,
diff --git a/apps/web/src/components/settings/ProviderInstanceCard.tsx b/apps/web/src/components/settings/ProviderInstanceCard.tsx
index f0040802a2e5e..69abe689129fb 100644
--- a/apps/web/src/components/settings/ProviderInstanceCard.tsx
+++ b/apps/web/src/components/settings/ProviderInstanceCard.tsx
@@ -17,7 +17,9 @@ import * as Arr from "effect/Array";
 import * as Result from "effect/Result";
 import { Fragment, useState, type ReactElement, type ReactNode } from "react";
 import {
+  FileLinkInstructionsSetting,
   isProviderDriverKind,
+  makeProviderSettingsSchema,
   resolveProviderInstanceEnabled,
   type ProviderInstanceConfig,
   type ProviderInstanceEnvironmentVariable,
@@ -80,6 +82,13 @@ import {
 
 const ENVIRONMENT_VARIABLE_NAME_PATTERN = /^[a-zA-Z_][a-zA-Z0-9_]*$/;
 
+// Connect with ChatGPT owns Codex's launch settings, but not the guidance its agents get.
+const CODEX_MANAGED_SETTINGS_FORM = {
+  settingsSchema: makeProviderSettingsSchema({
+    fileLinkInstructions: FileLinkInstructionsSetting,
+  }),
+};
+
 function ProviderStatusDiagnostic({
   detail,
   children,
@@ -1338,7 +1347,21 @@ export function ProviderInstanceCard({
             title="Runtime"
             headerPlacement="outside"
           >
-            {runtime ?? runtimeFields}
+            {runtime === undefined ? (
+              runtimeFields
+            ) : (
+              <>
+                {runtime}
+                <ProviderSettingsForm
+                  definition={CODEX_MANAGED_SETTINGS_FORM}
+                  value={instance.config}
+                  idPrefix={`provider-instance-${instanceId}`}
+                  variant="settings"
+                  onChange={updateConfig}
+                  environmentId={environmentId}
+                />
+              </>
+            )}
           </FoldedSettingsSection>
         </div>
       ) : !driverOption || deriveProviderSettingsFields(driverOption).length > 0 ? (
diff --git a/apps/web/src/components/settings/ProviderSettingsForm.test.ts b/apps/web/src/components/settings/ProviderSettingsForm.test.ts
index d59eb5c1238b9..2db5dec209c29 100644
--- a/apps/web/src/components/settings/ProviderSettingsForm.test.ts
+++ b/apps/web/src/components/settings/ProviderSettingsForm.test.ts
@@ -1,5 +1,7 @@
 import { describe, expect, it } from "vite-plus/test";
 import {
+  DEFAULT_FILE_LINK_INSTRUCTIONS,
+  FILE_LINK_INSTRUCTIONS_MAX_LENGTH,
   makeProviderSettingsSchema,
   ProviderDriverKind,
   SettingsSecretValue,
@@ -52,6 +54,40 @@ describe("ProviderSettingsForm helpers", () => {
     expect(next).toEqual({ forkOwned: 1 });
   });
 
+  it("keeps file link instructions unset until edited, within Codex's limit, and resettable", () => {
+    const claude = providerClients.get(ProviderDriverKind.make("claudeAgent"));
+    const field = deriveProviderSettingsFields(claude!).find(
+      ({ key }) => key === "fileLinkInstructions",
+    );
+    expect(field).toMatchObject({
+      control: "textarea",
+      defaultStringValue: DEFAULT_FILE_LINK_INSTRUCTIONS,
+      maxLength: FILE_LINK_INSTRUCTIONS_MAX_LENGTH,
+    });
+
+    expect(nextProviderConfigWithFieldValue(undefined, field!, "Cite files as URLs.")).toEqual({
+      fileLinkInstructions: "Cite files as URLs.",
+    });
+    expect(nextProviderConfigWithFieldValue({ launchArgs: "--chrome" }, field!, "")).toEqual({
+      launchArgs: "--chrome",
+      fileLinkInstructions: "",
+    });
+    expect(
+      nextProviderConfigWithFieldValue(
+        { launchArgs: "--chrome", fileLinkInstructions: "" },
+        field!,
+        DEFAULT_FILE_LINK_INSTRUCTIONS,
+      ),
+    ).toEqual({ launchArgs: "--chrome" });
+  });
+
+  it("offers file link instructions for local ACP agents", () => {
+    const acpRegistry = providerClients.get(ProviderDriverKind.make("acpRegistry"));
+    expect(
+      deriveProviderSettingsFields(acpRegistry!, { source: "local" }).map(({ key }) => key),
+    ).toEqual(["source", "commandPath", "fileLinkInstructions"]);
+  });
+
   it("stores false boolean fields when true is the default", () => {
     const next = nextProviderConfigWithFieldValue(
       undefined,
diff --git a/apps/web/src/components/settings/ProviderSettingsForm.tsx b/apps/web/src/components/settings/ProviderSettingsForm.tsx
index 646dfd80edc20..277a894e434dc 100644
--- a/apps/web/src/components/settings/ProviderSettingsForm.tsx
+++ b/apps/web/src/components/settings/ProviderSettingsForm.tsx
@@ -28,7 +28,7 @@ import type { ProviderClientDefinition } from "@t3tools/provider-core/client";
 export type SettingsFormDefinition = Pick<ProviderClientDefinition, "settingsSchema"> & {
   readonly driverKind?: ProviderClientDefinition["driverKind"];
 };
-import { SettingsRow } from "./settingsLayout";
+import { SettingResetButton, SettingsRow } from "./settingsLayout";
 
 export interface ProviderSettingsFieldModel {
   readonly key: string;
@@ -36,12 +36,14 @@ export interface ProviderSettingsFieldModel {
   readonly label: string;
   readonly description?: string | undefined;
   readonly placeholder?: string | undefined;
+  readonly maxLength?: number | undefined;
   readonly clearWhenEmpty: "omit" | "persist";
   /** Kept in the server's secret store: a saved value arrives as `SECRET_REDACTED` and never shows. */
   readonly secret?: boolean | undefined;
   /** Typed `SettingsSecretValue`: may name a secret provider reference instead of a value. */
   readonly acceptsSecretReference?: boolean | undefined;
   readonly defaultBooleanValue?: boolean | undefined;
+  readonly defaultStringValue?: string | undefined;
 
   readonly options?: ReadonlyArray<ProviderSettingsFormOption> | undefined;
 }
@@ -89,6 +91,16 @@ function readFieldBooleanDefault(
   return Option.isSome(decoded) && typeof decoded.value === "boolean" ? decoded.value : undefined;
 }
 
+function readFieldTextDefault(
+  fieldSchema: ProviderClientDefinition["settingsSchema"]["fields"][string],
+): string | undefined {
+  const decodeDefault = Schema.decodeUnknownOption(fieldSchema as Schema.Decoder<unknown>);
+  const decoded = decodeDefault(undefined);
+  return Option.isSome(decoded) && typeof decoded.value === "string" && decoded.value.length > 0
+    ? decoded.value
+    : undefined;
+}
+
 export function deriveProviderSettingsFields(
   definition: SettingsFormDefinition,
   value?: unknown,
@@ -114,7 +126,14 @@ export function deriveProviderSettingsFields(
       const fieldSchema = definition.settingsSchema.fields[key]!;
       const formAnnotation = readProviderSettingsFormAnnotation(fieldSchema);
       if (formAnnotation.hidden) return [];
-      if (isLocalAcp && key !== "source" && key !== "commandPath") return [];
+      if (
+        isLocalAcp &&
+        key !== "source" &&
+        key !== "commandPath" &&
+        key !== "fileLinkInstructions"
+      ) {
+        return [];
+      }
 
       const annotatedTitle = readFieldAnnotationString(fieldSchema, "title");
       const annotatedDescription = readFieldAnnotationString(fieldSchema, "description");
@@ -136,12 +155,18 @@ export function deriveProviderSettingsFields(
             : formAnnotation.placeholder !== undefined
               ? { placeholder: formAnnotation.placeholder }
               : {}),
+          ...(formAnnotation.maxLength !== undefined
+            ? { maxLength: formAnnotation.maxLength }
+            : {}),
           clearWhenEmpty: formAnnotation.clearWhenEmpty ?? "omit",
           ...(isSecretSetting(fieldSchema) ? { secret: true } : {}),
           ...(acceptsSecretReference(fieldSchema) ? { acceptsSecretReference: true } : {}),
           ...(formAnnotation.control === "switch"
             ? { defaultBooleanValue: readFieldBooleanDefault(fieldSchema) }
             : {}),
+          ...(formAnnotation.control === "textarea"
+            ? { defaultStringValue: readFieldTextDefault(fieldSchema) }
+            : {}),
           ...(formAnnotation.control === "select" && formAnnotation.options
             ? { options: formAnnotation.options }
             : {}),
@@ -284,10 +309,10 @@ function ProviderCommandArguments({
   );
 }
 
-function readProviderConfigString(config: unknown, key: string): string {
-  if (config === null || typeof config !== "object") return "";
+function readProviderConfigString(config: unknown, key: string, defaultValue = ""): string {
+  if (config === null || typeof config !== "object") return defaultValue;
   const value = (config as Record<string, unknown>)[key];
-  return typeof value === "string" ? value : "";
+  return typeof value === "string" ? value : defaultValue;
 }
 
 function readProviderConfigBoolean(config: unknown, key: string, defaultValue = false): boolean {
@@ -320,7 +345,10 @@ export function nextProviderConfigWithFieldValue(
   }
 
   const trimmed = value.trim();
-  if (field.clearWhenEmpty === "omit" && trimmed.length === 0) {
+  if (
+    (field.clearWhenEmpty === "omit" && trimmed.length === 0) ||
+    trimmed === field.defaultStringValue
+  ) {
     delete base[field.key];
   } else {
     base[field.key] = value;
@@ -434,6 +462,34 @@ function ProviderSettingsSelect({
   );
 }
 
+function ProviderSettingsTextarea({
+  field,
+  value,
+  onChange,
+  ...rest
+}: Pick<ProviderSettingsFieldRowProps, "field" | "value" | "onChange"> & {
+  readonly id: string;
+  readonly className?: string | undefined;
+  readonly "aria-describedby"?: string | undefined;
+}) {
+  const text = readProviderConfigString(value, field.key, field.defaultStringValue);
+  return (
+    <Textarea
+      {...rest}
+      key={text}
+      defaultValue={text}
+      onBlur={(event) => {
+        if (event.target.value !== text) {
+          onChange(nextProviderConfigWithFieldValue(value, field, event.target.value));
+        }
+      }}
+      placeholder={field.placeholder}
+      maxLength={field.maxLength}
+      spellCheck={false}
+    />
+  );
+}
+
 function FieldFrame(props: {
   readonly variant: ProviderSettingsFormProps["variant"];
   readonly children: ReactNode;
@@ -475,6 +531,7 @@ function ProviderSettingsFieldRow({
 
   if (variant === "settings") {
     const descriptionId = field.description ? `${inputId}-description` : undefined;
+    const defaultText = field.defaultStringValue;
     const secretConfigured =
       field.secret === true && readProviderConfigString(value, field.key).length > 0;
     const control =
@@ -497,16 +554,13 @@ function ProviderSettingsFieldRow({
           onChange={onChange}
         />
       ) : field.control === "textarea" ? (
-        <Textarea
+        <ProviderSettingsTextarea
+          field={field}
+          value={value}
           id={inputId}
           aria-describedby={descriptionId}
           className="w-full max-w-full @min-[32rem]/settings-row:w-[min(24rem,50cqw)]"
-          value={readProviderConfigString(value, field.key)}
-          onChange={(event) =>
-            onChange(nextProviderConfigWithFieldValue(value, field, event.target.value))
-          }
-          placeholder={field.placeholder}
-          spellCheck={false}
+          onChange={onChange}
         />
       ) : field.acceptsSecretReference && environmentId !== undefined ? (
         <SecretSettingsControl
@@ -565,6 +619,15 @@ function ProviderSettingsFieldRow({
         description={
           field.description ? <span id={descriptionId}>{field.description}</span> : undefined
         }
+        resetAction={
+          defaultText !== undefined &&
+          readProviderConfigString(value, field.key, defaultText) !== defaultText ? (
+            <SettingResetButton
+              label={field.label}
+              onClick={() => onChange(nextProviderConfigWithFieldValue(value, field, defaultText))}
+            />
+          ) : undefined
+        }
         control={control}
         managed={managedReason}
       />
@@ -615,15 +678,12 @@ function ProviderSettingsFieldRow({
       <FieldFrame variant={variant}>
         <label htmlFor={inputId} className={cn(variant === "card" && "block")}>
           {label}
-          <Textarea
+          <ProviderSettingsTextarea
+            field={field}
+            value={value}
             id={inputId}
             className={cn(variant === "card" && "mt-1.5")}
-            value={readProviderConfigString(value, field.key)}
-            onChange={(event) =>
-              onChange(nextProviderConfigWithFieldValue(value, field, event.target.value))
-            }
-            placeholder={field.placeholder}
-            spellCheck={false}
+            onChange={onChange}
           />
           {description}
         </label>
diff --git a/docs/user/composer.md b/docs/user/composer.md
index df880e49c6ca5..607c21ba065f8 100644
--- a/docs/user/composer.md
+++ b/docs/user/composer.md
@@ -406,6 +406,10 @@ File links refer to the environment's machine, including when you connect remote
 Previews use the original file, even outside the workspace. Moving or deleting it
 can break the preview, so save a copy if you need to keep it.
 
+T3 Code asks agents to embed media and link files by absolute path so they open here.
+To give an agent different guidance, or none, edit **File link instructions** in that
+provider's settings under **Settings → Providers**.
+
 ## Files outside the workspace
 
 Follow an agent's file link to read a report or other file outside the workspace.
diff --git a/evals/mcp-tool-use/README.md b/evals/mcp-tool-use/README.md
index c5802a35af63b..ff034060fb291 100644
--- a/evals/mcp-tool-use/README.md
+++ b/evals/mcp-tool-use/README.md
@@ -246,6 +246,7 @@ After the change, the first reference to a file is an absolute link. The remaini
 ## Where T3's text lives
 
 - `packages/provider-core/src/server/runtimeInstructions.ts`
+- `packages/contracts/src/settings.ts` (`DEFAULT_FILE_LINK_INSTRUCTIONS`)
 - `packages/provider-core/src/server/orchestrationInstructions.ts`
 - `apps/server/src/provider/CodexDeveloperInstructions.ts`
 - `apps/server/src/mcp/toolkits/*/tools.ts` (tool descriptions)
diff --git a/packages/contracts/src/settings.test.ts b/packages/contracts/src/settings.test.ts
index a5a27235bbe7c..c34ad2f8e9e4c 100644
--- a/packages/contracts/src/settings.test.ts
+++ b/packages/contracts/src/settings.test.ts
@@ -11,7 +11,9 @@ import {
   ClientSettingsSchema,
   ClientSettingsPatch,
   ClaudeSettings,
+  DEFAULT_FILE_LINK_INSTRUCTIONS,
   DEFAULT_SERVER_SETTINGS,
+  FILE_LINK_INSTRUCTIONS_MAX_LENGTH,
   globalIdleCompaction,
   idleCompactionPatch,
   PROJECT_SCOPED_SERVER_SETTING_KEYS,
@@ -252,6 +254,18 @@ describe("custom model settings", () => {
   });
 });
 
+describe("file link instructions", () => {
+  it("sends the shipped text when unset, none when cleared, and rejects text Codex would truncate", () => {
+    expect(decodeClaudeSettings({}).fileLinkInstructions).toBe(DEFAULT_FILE_LINK_INSTRUCTIONS);
+    expect(decodeClaudeSettings({ fileLinkInstructions: " \n " }).fileLinkInstructions).toBe("");
+    expect(() =>
+      decodeClaudeSettings({
+        fileLinkInstructions: "x".repeat(FILE_LINK_INSTRUCTIONS_MAX_LENGTH + 1),
+      }),
+    ).toThrow();
+  });
+});
+
 describe("resolveIdleCompaction", () => {
   it("lets a Claude instance override the global default", () => {
     const settings = decodeServerSettings({
diff --git a/packages/contracts/src/settings.ts b/packages/contracts/src/settings.ts
index cd112d84bf9f4..ad5b979fe7cb1 100644
--- a/packages/contracts/src/settings.ts
+++ b/packages/contracts/src/settings.ts
@@ -603,6 +603,28 @@ export const makeBinaryPathSetting = (fallback: string) =>
     Schema.withDecodingDefault(Effect.succeed(fallback)),
   );
 
+export const DEFAULT_FILE_LINK_INSTRUCTIONS =
+  "You can embed images, video, and audio in your response using Markdown image syntax with absolute file paths. Link every other file you cite or produce by its absolute path, as in [http.ts:42](/abs/path/http.ts:42), so the user can open it in T3 Code's files viewer.";
+
+// Keeps Codex's runtime context entry under its 4,000-byte cap, past which it drops the PR rules.
+export const FILE_LINK_INSTRUCTIONS_MAX_LENGTH = 800;
+
+export const FileLinkInstructionsSetting = TrimmedString.check(
+  Schema.isMaxLength(FILE_LINK_INSTRUCTIONS_MAX_LENGTH),
+).pipe(
+  Schema.withDecodingDefault(Effect.succeed(DEFAULT_FILE_LINK_INSTRUCTIONS)),
+  Schema.annotateKey({
+    title: "File link instructions",
+    description: `How T3 Code tells agents to show media and link files. Up to ${FILE_LINK_INSTRUCTIONS_MAX_LENGTH} characters; clear it to send none.`,
+    providerSettingsForm: {
+      control: "textarea",
+      placeholder: "None",
+      maxLength: FILE_LINK_INSTRUCTIONS_MAX_LENGTH,
+      clearWhenEmpty: "persist",
+    },
+  }),
+);
+
 export type ProviderSettingsFormControl = "text" | "password" | "textarea" | "switch" | "select";
 
 export interface ProviderSettingsFormOption {
@@ -613,6 +635,7 @@ export interface ProviderSettingsFormOption {
 export interface ProviderSettingsFormAnnotation {
   readonly control?: ProviderSettingsFormControl | undefined;
   readonly placeholder?: string | undefined;
+  readonly maxLength?: number | undefined;
   readonly hidden?: boolean | undefined;
   readonly clearWhenEmpty?: "omit" | "persist" | undefined;
 
@@ -722,13 +745,14 @@ export const CodexSettings = makeProviderSettingsSchema(
         description: "Additional CLI arguments passed to codex app-server on session start.",
       }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
     customModels: Schema.Array(CustomModelSetting).pipe(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
   },
   {
-    order: ["binaryPath", "homePath", "shadowHomePath", "launchArgs"],
+    order: ["binaryPath", "homePath", "shadowHomePath", "launchArgs", "fileLinkInstructions"],
   },
 );
 export type CodexSettings = typeof CodexSettings.Type;
@@ -792,6 +816,7 @@ export const ClaudeSettings = makeProviderSettingsSchema(
         },
       }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
     autoCompactWindow: TrimmedString.check(
       Schema.isPattern(CLAUDE_AUTO_COMPACT_WINDOW_PATTERN),
     ).pipe(
@@ -821,7 +846,14 @@ export const ClaudeSettings = makeProviderSettingsSchema(
     ),
   },
   {
-    order: ["binaryPath", "homePath", "autoCompactWindow", "idleCompaction", "launchArgs"],
+    order: [
+      "binaryPath",
+      "homePath",
+      "autoCompactWindow",
+      "idleCompaction",
+      "launchArgs",
+      "fileLinkInstructions",
+    ],
   },
 );
 export type ClaudeSettings = typeof ClaudeSettings.Type;
@@ -894,12 +926,22 @@ export const AntigravitySettings = makeProviderSettingsSchema(
         providerSettingsForm: { placeholder: "Automatic", clearWhenEmpty: "persist" },
       }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
     customModels: Schema.Array(CustomModelSetting).pipe(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
   },
-  { order: ["authMethod", "apiKey", "gcpProject", "gcpLocation", "binaryPath"] },
+  {
+    order: [
+      "authMethod",
+      "apiKey",
+      "gcpProject",
+      "gcpLocation",
+      "binaryPath",
+      "fileLinkInstructions",
+    ],
+  },
 );
 export type AntigravitySettings = typeof AntigravitySettings.Type;
 
diff --git a/packages/provider-acp-registry/src/server/adapter.ts b/packages/provider-acp-registry/src/server/adapter.ts
index 1b8b4240fd00e..21be281101070 100644
--- a/packages/provider-acp-registry/src/server/adapter.ts
+++ b/packages/provider-acp-registry/src/server/adapter.ts
@@ -291,6 +291,7 @@ export const makeAcpRegistryAdapterV2 = Effect.fn("makeAcpRegistryAdapterV2")(fu
   return yield* makeAcpAdapterV2({
     instanceId: options.instanceId,
     flavor,
+    fileLinkInstructions: options.settings.fileLinkInstructions,
     selfInvocation: options.selfInvocation,
     ...(options.continuationRequests === undefined
       ? {}
diff --git a/packages/provider-acp-registry/src/settings.ts b/packages/provider-acp-registry/src/settings.ts
index 7d5b4173d512f..c389188856a97 100644
--- a/packages/provider-acp-registry/src/settings.ts
+++ b/packages/provider-acp-registry/src/settings.ts
@@ -1,4 +1,8 @@
-import { TrimmedString, makeProviderSettingsSchema } from "@t3tools/contracts";
+import {
+  TrimmedString,
+  makeProviderSettingsSchema,
+  FileLinkInstructionsSetting,
+} from "@t3tools/contracts";
 import * as Effect from "effect/Effect";
 import * as Schema from "effect/Schema";
 
@@ -62,9 +66,10 @@ export const AcpRegistrySettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
   },
   {
-    order: ["source", "agentId", "commandPath", "authMethodId"],
+    order: ["source", "agentId", "commandPath", "authMethodId", "fileLinkInstructions"],
   },
 );
 export type AcpRegistrySettings = typeof AcpRegistrySettings.Type;
diff --git a/packages/provider-acp/src/server/adapter.ts b/packages/provider-acp/src/server/adapter.ts
index a2c2c429fa88c..c706b17b1211c 100644
--- a/packages/provider-acp/src/server/adapter.ts
+++ b/packages/provider-acp/src/server/adapter.ts
@@ -620,6 +620,7 @@ export interface AcpAdapterV2SubagentUpdate {
 export interface AcpAdapterV2Options {
   readonly instanceId: ProviderInstanceId;
   readonly flavor: AcpAdapterV2Flavor;
+  readonly fileLinkInstructions?: string | undefined;
   readonly selfInvocation: SelfInvocation;
   readonly clientTerminals?: {
     readonly environment?: NodeJS.ProcessEnv;
@@ -8025,6 +8026,7 @@ export const makeAcpAdapterV2 = Effect.fn("makeAcpAdapterV2")(function* (
               text: buildRuntimeInstructions({
                 harness: flavor.runtimeHarness ?? driver,
                 model: turnInput.modelSelection.model,
+                fileLinkInstructions: options.fileLinkInstructions,
                 pullRequestLinking:
                   sessionSetup === null ||
                   flavor.sessionCarriesPullRequestLinking?.(sessionSetup.initializeResult) !== true,
diff --git a/packages/provider-core/src/server/runtimeInstructions.test.ts b/packages/provider-core/src/server/runtimeInstructions.test.ts
index bbc4aadb23f26..7b708fd74b6d5 100644
--- a/packages/provider-core/src/server/runtimeInstructions.test.ts
+++ b/packages/provider-core/src/server/runtimeInstructions.test.ts
@@ -1,8 +1,36 @@
 import { assert, describe, it } from "@effect/vitest";
+import { DEFAULT_FILE_LINK_INSTRUCTIONS } from "@t3tools/contracts";
 
-import { buildRuntimeInstructions } from "./runtimeInstructions.ts";
+import {
+  buildRuntimeInstructions,
+  PULL_REQUEST_LINKING_INSTRUCTIONS,
+} from "./runtimeInstructions.ts";
 
 describe("buildRuntimeInstructions", () => {
+  it("sends the instance's file link instructions after the runtime identity, and the shipped text by default", () => {
+    const runtime = { harness: "Codex", model: "gpt-6.1-sol", reasoningEffort: "high" };
+    const identity =
+      "<runtime_info>In case you're asked: you are running in T3 Code through the Codex harness, as gpt-6.1-sol with high reasoning effort. No need to mention this otherwise.";
+    const shipped = `${identity} You can embed images, video, and audio in your response using Markdown image syntax with absolute file paths. Link every other file you cite or produce by its absolute path, as in [http.ts:42](/abs/path/http.ts:42), so the user can open it in T3 Code's files viewer.</runtime_info>\n\n${PULL_REQUEST_LINKING_INSTRUCTIONS}`;
+
+    assert.strictEqual(buildRuntimeInstructions(runtime), shipped);
+    assert.strictEqual(
+      buildRuntimeInstructions({
+        ...runtime,
+        fileLinkInstructions: DEFAULT_FILE_LINK_INSTRUCTIONS,
+      }),
+      shipped,
+    );
+    assert.strictEqual(
+      buildRuntimeInstructions({ ...runtime, fileLinkInstructions: "Link files as browser URLs." }),
+      `${identity} Link files as browser URLs.</runtime_info>\n\n${PULL_REQUEST_LINKING_INSTRUCTIONS}`,
+    );
+    assert.strictEqual(
+      buildRuntimeInstructions({ ...runtime, fileLinkInstructions: "" }),
+      `${identity}</runtime_info>\n\n${PULL_REQUEST_LINKING_INSTRUCTIONS}`,
+    );
+  });
+
   it("leaves PR linking to a session that already carries it, and keeps runtime identity", () => {
     const instructions = buildRuntimeInstructions({
       harness: "Antigravity",
diff --git a/packages/provider-core/src/server/runtimeInstructions.ts b/packages/provider-core/src/server/runtimeInstructions.ts
index 88c4985a3bcc6..3762702973aa7 100644
--- a/packages/provider-core/src/server/runtimeInstructions.ts
+++ b/packages/provider-core/src/server/runtimeInstructions.ts
@@ -1,3 +1,5 @@
+import { DEFAULT_FILE_LINK_INSTRUCTIONS } from "@t3tools/contracts";
+
 /** Session-invariant; harnesses with a native system-prompt append can carry it once per session. */
 export const PULL_REQUEST_LINKING_INSTRUCTIONS = `<pull_request_linking>
 Link each PR you create, take over, or push to: link_pull_request, or link_pull_requests for several, full URL, every stack layer, as your next call. Host tools do not link for you. If linking fails, say so. Skip PRs you only read or review, and PRs named only as background. Call watch_pull_request when asked to monitor or babysit, or when work you were asked to do, such as a merge, still waits on checks or reviews, even after an earlier unwatch. Finish any needed branch update and push first, then watch and end your turn. Otherwise act now or hand back. Delegated children never watch, even if the brief says babysit. After PR work, a child's last line is: PR <full URL>, head <SHA>, checks and reviews <state>. Links and watches persist across pushes. For PR waits, no sleep, loops, gh --watch, Monitor or ScheduleWakeup. Before handback, call unwatch_pull_request on any PR you watch.
@@ -9,6 +11,7 @@ export function buildRuntimeInstructions(runtime: {
   readonly model?: string | undefined;
   readonly modelName?: string | undefined;
   readonly reasoningEffort?: string | undefined;
+  readonly fileLinkInstructions?: string | undefined;
   /** False when the session's system prompt already carries the linking instructions. */
   readonly pullRequestLinking?: boolean;
 }): string {
@@ -20,7 +23,9 @@ export function buildRuntimeInstructions(runtime: {
     modelName && modelName !== model ? `${modelName} (model slug: ${model})` : model;
   const modelInfo = model && model !== "auto" && model !== "default" ? `, as ${modelLabel}` : "";
   const effortInfo = effort ? ` with ${effort} reasoning effort` : "";
-  const runtimeInfo = `<runtime_info>In case you're asked: you are running in T3 Code through the ${harness} harness${modelInfo}${effortInfo}. No need to mention this otherwise. You can embed images, video, and audio in your response using Markdown image syntax with absolute file paths. Link every other file you cite or produce by its absolute path, as in [http.ts:42](/abs/path/http.ts:42), so the user can open it in T3 Code's files viewer.</runtime_info>`;
+  const fileLinks = runtime.fileLinkInstructions ?? DEFAULT_FILE_LINK_INSTRUCTIONS;
+  const fileLinkInfo = fileLinks ? ` ${fileLinks}` : "";
+  const runtimeInfo = `<runtime_info>In case you're asked: you are running in T3 Code through the ${harness} harness${modelInfo}${effortInfo}. No need to mention this otherwise.${fileLinkInfo}</runtime_info>`;
   return runtime.pullRequestLinking === false
     ? runtimeInfo
     : `${runtimeInfo}\n\n${PULL_REQUEST_LINKING_INSTRUCTIONS}`;
diff --git a/packages/provider-cursor/src/server/adapter.ts b/packages/provider-cursor/src/server/adapter.ts
index f5fbd0630d478..d23383d11e4e4 100644
--- a/packages/provider-cursor/src/server/adapter.ts
+++ b/packages/provider-cursor/src/server/adapter.ts
@@ -962,6 +962,7 @@ interface CursorLiveAgent {
 export interface CursorAdapterV2Options {
   readonly instanceId: ProviderInstanceId;
   readonly environment: NodeJS.ProcessEnv;
+  readonly fileLinkInstructions?: string | undefined;
   readonly getModels?: () => ReadonlyArray<ServerProviderModel>;
 }
 
@@ -2371,7 +2372,11 @@ export const makeCursorAdapterV2 = Effect.fn("makeCursorAdapterV2")(function* (
               detail: "Cursor turn requires non-empty text or attachments.",
             });
           }
-          const text = `${userText}\n\n${buildRuntimeInstructions({ harness: "Cursor", model: turnInput.modelSelection.model })}`;
+          const text = `${userText}\n\n${buildRuntimeInstructions({
+            harness: "Cursor",
+            model: turnInput.modelSelection.model,
+            fileLinkInstructions: adapterOptions.fileLinkInstructions,
+          })}`;
           return {
             message: images.length === 0 ? text : ({ text, images } satisfies SDKUserMessage),
             prompt: userText,
diff --git a/packages/provider-cursor/src/server/driver.ts b/packages/provider-cursor/src/server/driver.ts
index ef50abb0a93b4..68fea91b59479 100644
--- a/packages/provider-cursor/src/server/driver.ts
+++ b/packages/provider-cursor/src/server/driver.ts
@@ -165,6 +165,7 @@ export const CursorDriver: ProviderDriver<
     const orchestrationAdapter = yield* makeCursorAdapterV2({
       instanceId,
       environment: processEnv,
+      fileLinkInstructions: effectiveConfig.fileLinkInstructions,
       getModels: () => catalogModels,
     }).pipe(
       Effect.provideService(CursorAgentSdk.CursorAgentSdkRunner, {
diff --git a/packages/provider-cursor/src/settings.ts b/packages/provider-cursor/src/settings.ts
index a244c5db49212..4c0407283222a 100644
--- a/packages/provider-cursor/src/settings.ts
+++ b/packages/provider-cursor/src/settings.ts
@@ -1,4 +1,9 @@
-import { CustomModelSetting, makeProviderSettingsSchema, TrimmedString } from "@t3tools/contracts";
+import {
+  CustomModelSetting,
+  makeProviderSettingsSchema,
+  FileLinkInstructionsSetting,
+  TrimmedString,
+} from "@t3tools/contracts";
 import * as Effect from "effect/Effect";
 import * as Schema from "effect/Schema";
 
@@ -19,9 +24,10 @@ export const CursorSettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
   },
   {
-    order: [],
+    order: ["fileLinkInstructions"],
   },
 );
 export type CursorSettings = typeof CursorSettings.Type;
diff --git a/packages/provider-fx/src/server/adapter.ts b/packages/provider-fx/src/server/adapter.ts
index b48293f4fb986..f91e38c46c152 100644
--- a/packages/provider-fx/src/server/adapter.ts
+++ b/packages/provider-fx/src/server/adapter.ts
@@ -198,6 +198,7 @@ export const makeFxAdapterV2 = Effect.fn("makeFxAdapterV2")(function* (
   return yield* makeAcpAdapterV2({
     instanceId: options.instanceId,
     flavor: makeFxAcpAdapterFlavor(options),
+    fileLinkInstructions: options.settings.fileLinkInstructions,
     selfInvocation: options.selfInvocation,
     ...(options.nativeLogging === undefined ? {} : { nativeLogging: options.nativeLogging }),
     ...(options.testHooks === undefined ? {} : { testHooks: options.testHooks }),
diff --git a/packages/provider-fx/src/settings.ts b/packages/provider-fx/src/settings.ts
index fd94e3e57e60a..af444c48eab8c 100644
--- a/packages/provider-fx/src/settings.ts
+++ b/packages/provider-fx/src/settings.ts
@@ -8,6 +8,7 @@ import {
   CustomModelSetting,
   makeBinaryPathSetting,
   makeProviderSettingsSchema,
+  FileLinkInstructionsSetting,
 } from "@t3tools/contracts";
 import * as Effect from "effect/Effect";
 import * as Schema from "effect/Schema";
@@ -29,9 +30,10 @@ export const FxSettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
   },
   {
-    order: ["binaryPath"],
+    order: ["binaryPath", "fileLinkInstructions"],
   },
 );
 export type FxSettings = typeof FxSettings.Type;
diff --git a/packages/provider-grok/src/server/adapter.ts b/packages/provider-grok/src/server/adapter.ts
index 9ed1368f16984..74f49ad1e0154 100644
--- a/packages/provider-grok/src/server/adapter.ts
+++ b/packages/provider-grok/src/server/adapter.ts
@@ -347,6 +347,7 @@ export const makeGrokAdapterV2 = Effect.fn("makeGrokAdapterV2")(function* (
   return yield* makeAcpAdapterV2({
     instanceId: options.instanceId,
     flavor: makeGrokAcpAdapterFlavor(options, yield* HostProcess.HomeDirectory),
+    fileLinkInstructions: options.settings.fileLinkInstructions,
     selfInvocation: options.selfInvocation,
     ...(options.nativeLogging === undefined ? {} : { nativeLogging: options.nativeLogging }),
     ...(options.continuationRequests === undefined
diff --git a/packages/provider-grok/src/settings.ts b/packages/provider-grok/src/settings.ts
index 3796a5578ab6d..abc3a00cbcace 100644
--- a/packages/provider-grok/src/settings.ts
+++ b/packages/provider-grok/src/settings.ts
@@ -2,6 +2,7 @@ import {
   CustomModelSetting,
   makeBinaryPathSetting,
   makeProviderSettingsSchema,
+  FileLinkInstructionsSetting,
 } from "@t3tools/contracts";
 import * as Effect from "effect/Effect";
 import * as Schema from "effect/Schema";
@@ -23,9 +24,10 @@ export const GrokSettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
   },
   {
-    order: ["binaryPath"],
+    order: ["binaryPath", "fileLinkInstructions"],
   },
 );
 export type GrokSettings = typeof GrokSettings.Type;
diff --git a/packages/provider-kiro/src/server/adapter.ts b/packages/provider-kiro/src/server/adapter.ts
index 6815b60e8f227..890fa9533869f 100644
--- a/packages/provider-kiro/src/server/adapter.ts
+++ b/packages/provider-kiro/src/server/adapter.ts
@@ -582,6 +582,7 @@ export const makeKiroAdapterV2 = Effect.fn("makeKiroAdapterV2")(function* (
   return yield* makeAcpAdapterV2({
     instanceId: options.instanceId,
     flavor: makeKiroAcpAdapterFlavor(options),
+    fileLinkInstructions: options.settings.fileLinkInstructions,
     selfInvocation: options.selfInvocation,
     ...(options.nativeLogging === undefined ? {} : { nativeLogging: options.nativeLogging }),
     ...(options.testHooks === undefined ? {} : { testHooks: options.testHooks }),
diff --git a/packages/provider-kiro/src/settings.ts b/packages/provider-kiro/src/settings.ts
index 4ae61a3910907..dd501e89548ec 100644
--- a/packages/provider-kiro/src/settings.ts
+++ b/packages/provider-kiro/src/settings.ts
@@ -2,6 +2,7 @@ import {
   CustomModelSetting,
   makeBinaryPathSetting,
   makeProviderSettingsSchema,
+  FileLinkInstructionsSetting,
 } from "@t3tools/contracts";
 import * as Effect from "effect/Effect";
 import * as Schema from "effect/Schema";
@@ -24,9 +25,10 @@ export const KiroSettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
   },
   {
-    order: ["binaryPath"],
+    order: ["binaryPath", "fileLinkInstructions"],
   },
 );
 export type KiroSettings = typeof KiroSettings.Type;
diff --git a/packages/provider-muse/src/server/adapter.ts b/packages/provider-muse/src/server/adapter.ts
index 82e1adcb42277..ef9fc3fe1f771 100644
--- a/packages/provider-muse/src/server/adapter.ts
+++ b/packages/provider-muse/src/server/adapter.ts
@@ -2179,6 +2179,7 @@ export const makeMuseAdapterV2 = Effect.fn("makeMuseAdapterV2")(function* (
                       harness: "Muse Code",
                       model: session.model ?? undefined,
                       reasoningEffort: effort,
+                      fileLinkInstructions: options.settings.fileLinkInstructions,
                     }),
                   },
                   ...parts,
diff --git a/packages/provider-muse/src/settings.ts b/packages/provider-muse/src/settings.ts
index b9d32cadfb203..8b79f62ebaf9e 100644
--- a/packages/provider-muse/src/settings.ts
+++ b/packages/provider-muse/src/settings.ts
@@ -3,6 +3,7 @@ import {
   CustomModelSetting,
   makeBinaryPathSetting,
   makeProviderSettingsSchema,
+  FileLinkInstructionsSetting,
 } from "@t3tools/contracts";
 import * as Effect from "effect/Effect";
 import * as Schema from "effect/Schema";
@@ -25,7 +26,8 @@ export const MuseSettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
   },
-  { order: ["binaryPath"] },
+  { order: ["binaryPath", "fileLinkInstructions"] },
 );
 export type MuseSettings = typeof MuseSettings.Type;
diff --git a/packages/provider-opencode/src/server/adapter.ts b/packages/provider-opencode/src/server/adapter.ts
index a1b5ccb008ebe..079cb1aa643b4 100644
--- a/packages/provider-opencode/src/server/adapter.ts
+++ b/packages/provider-opencode/src/server/adapter.ts
@@ -2965,7 +2965,11 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
             ...(variant === undefined ? {} : { variant }),
             system: [
               orchestrationSystemPrompt,
-              buildRuntimeInstructions({ harness: "OpenCode", model: turn.modelSelection.model }),
+              buildRuntimeInstructions({
+                harness: "OpenCode",
+                model: turn.modelSelection.model,
+                fileLinkInstructions: options.settings.fileLinkInstructions,
+              }),
             ]
               .filter(Boolean)
               .join("\n\n"),
diff --git a/packages/provider-opencode/src/server/driver.ts b/packages/provider-opencode/src/server/driver.ts
index 5c60ccfe43278..2502806c3a778 100644
--- a/packages/provider-opencode/src/server/driver.ts
+++ b/packages/provider-opencode/src/server/driver.ts
@@ -329,7 +329,7 @@ export const OpenCodeDriver: ProviderDriver<
       probe: runtimeProbe,
       resolve: resolveRuntime,
       v1: openCodeV1Adapter,
-      v2: yield* OpenCode2AdapterV2.make(instanceId).pipe(
+      v2: yield* OpenCode2AdapterV2.make(instanceId, effectiveConfig.fileLinkInstructions).pipe(
         Effect.provideService(OpenCode2Server.OpenCode2Server, openCode2Server),
       ),
     });
diff --git a/packages/provider-opencode/src/server/v2/adapter.ts b/packages/provider-opencode/src/server/v2/adapter.ts
index 2cdae4df11723..a2c5c6fe0b6dc 100644
--- a/packages/provider-opencode/src/server/v2/adapter.ts
+++ b/packages/provider-opencode/src/server/v2/adapter.ts
@@ -679,7 +679,10 @@ const turnTokenUsage = (turn: ActiveTurn, status: OrchestrationV2ProviderTurn["s
       };
 };
 
-export const make = Effect.fn("OpenCode2Adapter.make")(function* (instanceId: ProviderInstanceId) {
+export const make = Effect.fn("OpenCode2Adapter.make")(function* (
+  instanceId: ProviderInstanceId,
+  fileLinkInstructions?: string | undefined,
+) {
   const server = yield* OpenCode2Server.OpenCode2Server;
   const idAllocator = yield* IdAllocator.IdAllocatorV2;
   const host = yield* ProviderHost.ProviderHost;
@@ -3269,7 +3272,11 @@ export const make = Effect.fn("OpenCode2Adapter.make")(function* (instanceId: Pr
         if (mcpAvailable) state.mcp = wanted;
       }
       const instructions = [
-        buildRuntimeInstructions({ harness: "OpenCode", model: turnInput.modelSelection.model }),
+        buildRuntimeInstructions({
+          harness: "OpenCode",
+          model: turnInput.modelSelection.model,
+          fileLinkInstructions,
+        }),
         t3OrchestrationSystemPrompt(mcpAvailable, mcpSession?.capabilities?.has("device") === true),
       ]
         .filter((part) => part !== undefined && part.length > 0)
diff --git a/packages/provider-opencode/src/settings.ts b/packages/provider-opencode/src/settings.ts
index 4391821bb5e97..4cfe5756c6bef 100644
--- a/packages/provider-opencode/src/settings.ts
+++ b/packages/provider-opencode/src/settings.ts
@@ -3,6 +3,7 @@ import {
   CustomModelSetting,
   makeBinaryPathSetting,
   makeProviderSettingsSchema,
+  FileLinkInstructionsSetting,
   secretSetting,
   SettingsSecretValue,
   TrimmedString,
@@ -54,9 +55,10 @@ export const OpenCodeSettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed([])),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
+    fileLinkInstructions: FileLinkInstructionsSetting,
   },
   {
-    order: ["binaryPath", "serverUrl", "serverPassword"],
+    order: ["binaryPath", "serverUrl", "serverPassword", "fileLinkInstructions"],
   },
 );
 export type OpenCodeSettings = typeof OpenCodeSettings.Type;