diff --git a/apps/desktop/src/main/__tests__/skills.test.ts b/apps/desktop/src/main/__tests__/skills.test.ts
index 9cb94764cda..3987f9da7fd 100644
--- a/apps/desktop/src/main/__tests__/skills.test.ts
+++ b/apps/desktop/src/main/__tests__/skills.test.ts
@@ -108,11 +108,11 @@ Use the Office tools.`);
     assert.match(mainProcess, /hostCapabilities: desktopHostCapabilities/);
     assert.match(mainProcess, /buildSkillsPromptFragment\(\s*skillSource,\s*options\?\.host \?\? deps\.host \?\? deps\.hostCapabilities,\s*options\?\.skillBudget,\s*\)/);
     assert.match(mainProcess, /buildSkillAgentTool\([\s\S]*resolveDesktopSkillHost(?:,\s*)?\)/);
-    assert.match(mainProcess, /const backendSkillHost: HostCapabilities =/);
+    assert.match(mainProcess, /const backendSkillHost = buildHostCapabilitiesFromBinding\(backendToolNames\)/);
+    assert.doesNotMatch(mainProcess, /const backendCapabilities = new Set<string>\(\)/);
     assert.match(mainProcess, /\[\.\.\.builtinTools, \.\.\.buildMcpTools\(mcpManager\)\]/);
     assert.match(mainProcess, /const backendTools = computerUseToolsForModel\(/);
     assert.match(mainProcess, /const backendToolNames = new Set\(/);
-    assert.match(mainProcess, /if \(tools\.some\(\(tool\) => backendToolNames\.has\(tool\.name\)\)\) backendCapabilities\.add\(capability\)/);
     assert.match(mainProcess, /backendTools\.map\(\(tool\) => tool\.name\)/);
     assert.match(mainProcess, /if \(!ctx\.tools\) desktopSessionSkillHosts\.set\(ctx\.sessionId, backendSkillHost\)/);
     assert.match(mainProcess, /host: backendSkillHost/);
diff --git a/apps/desktop/src/main/main.ts b/apps/desktop/src/main/main.ts
index 86a2586213c..49259413a56 100644
--- a/apps/desktop/src/main/main.ts
+++ b/apps/desktop/src/main/main.ts
@@ -679,9 +679,6 @@ backends.register('ai-sdk', createAiSdkBackendFactory({
   telemetryRepo,
   artifactStore,
   desktopSessionSkillHosts,
-  riveTools,
-  officeTools,
-  browserTools,
   computerUseTools,
   agentTeamLeadTools,
   builtinTools,
diff --git a/apps/desktop/src/main/session-stream.ts b/apps/desktop/src/main/session-stream.ts
index b11adad514a..e64c6ac0d9a 100644
--- a/apps/desktop/src/main/session-stream.ts
+++ b/apps/desktop/src/main/session-stream.ts
@@ -7,6 +7,7 @@ import {
   AiSdkBackend,
   buildDefaultContextBudgetPolicy,
   buildExpertDispatchToolForTeamId,
+  buildHostCapabilitiesFromBinding,
   buildLlmHistorySummarizer,
   buildMcpTools,
   buildProviderOptions,
@@ -85,9 +86,6 @@ export interface AiSdkBackendFactoryDeps {
   telemetryRepo: TelemetryRepo;
   artifactStore: ArtifactStore;
   desktopSessionSkillHosts: Map<string, HostCapabilities>;
-  riveTools: AssembledTools['riveTools'];
-  officeTools: AssembledTools['officeTools'];
-  browserTools: AssembledTools['browserTools'];
   computerUseTools: AssembledTools['computerUseTools'];
   agentTeamLeadTools: AssembledTools['agentTeamLeadTools'];
   builtinTools: AssembledTools['builtinTools'];
@@ -123,9 +121,6 @@ export function createAiSdkBackendFactory(deps: AiSdkBackendFactoryDeps): Backen
     telemetryRepo,
     artifactStore,
     desktopSessionSkillHosts,
-    riveTools,
-    officeTools,
-    browserTools,
     computerUseTools,
     agentTeamLeadTools,
     builtinTools,
@@ -179,19 +174,7 @@ export function createAiSdkBackendFactory(deps: AiSdkBackendFactoryDeps): Backen
       ...backendTools.map((tool) => tool.name),
       ...(expertDispatchTool ? [expertDispatchTool.name, ...agentTeamLeadTools.map((tool) => tool.name)] : []),
     ]);
-    const backendCapabilities = new Set<string>();
-    for (const [capability, tools] of [
-      ['rive', riveTools],
-      ['office', officeTools],
-      ['browser', browserTools],
-      ['computer_use', computerUseTools],
-    ] as const) {
-      if (tools.some((tool) => backendToolNames.has(tool.name))) backendCapabilities.add(capability);
-    }
-    const backendSkillHost: HostCapabilities = {
-      toolNames: backendToolNames,
-      capabilities: backendCapabilities,
-    };
+    const backendSkillHost = buildHostCapabilitiesFromBinding(backendToolNames);
     // Child backends share the parent sessionId but intentionally have a
     // narrower tool surface. They do not receive the Desktop Skill tool, so
     // they must not overwrite the parent session's resolver entry.
diff --git a/packages/runtime/src/skills.ts b/packages/runtime/src/skills.ts
index a405a67962a..2620a732c50 100644
--- a/packages/runtime/src/skills.ts
+++ b/packages/runtime/src/skills.ts
@@ -504,7 +504,7 @@ export async function buildSkillsPromptFragment(
   let skills = (await scanSkills(source)).filter((skill) => skill.enabled);
   // Gate before prompt-budget truncation so a host lacking a required tool
   // never advertises the skill. `host === undefined` keeps the legacy
-  // no-gating behavior (desktop call sites stay unchanged).
+  // no-gating behavior.
   if (host) skills = gateSkillsByHostCapabilities(skills, host).filter((gated) => gated.eligible);
   if (skills.length === 0) return undefined;
 
@@ -575,8 +575,7 @@ export function loadSkillInstructionsFromScan(
   const raw = typeof name === 'string' ? name.trim() : '';
   const enabledSkills = skills.filter((skill) => skill.enabled);
   // Gate eligible skills before exposing them as available or loading them.
-  // `host === undefined` keeps the legacy no-gating behavior (desktop call
-  // sites stay unchanged).
+  // `host === undefined` keeps the legacy no-gating behavior.
   const gated = host
     ? gateSkillsByHostCapabilities(enabledSkills, host)
     : enabledSkills.map((skill) => ({