diff --git a/packages/server/src/server/agent/activity-curator.test.ts b/packages/server/src/server/agent/activity-curator.test.ts
index ceea22612..f6dfc7bb5 100644
--- a/packages/server/src/server/agent/activity-curator.test.ts
+++ b/packages/server/src/server/agent/activity-curator.test.ts
@@ -6,8 +6,8 @@ function toolCallItem(params: {
   callId: string;
   name: string;
   status?: "running" | "completed" | "failed" | "canceled";
-  input?: unknown | null;
-  output?: unknown | null;
+  input?: unknown;
+  output?: unknown;
   error?: unknown;
   metadata?: Record<string, unknown>;
   detail?: Extract<AgentTimelineItem, { type: "tool_call" }>["detail"];
diff --git a/packages/server/src/server/agent/agent-sdk-types.ts b/packages/server/src/server/agent/agent-sdk-types.ts
index 5b2b5fc11..661c28025 100644
--- a/packages/server/src/server/agent/agent-sdk-types.ts
+++ b/packages/server/src/server/agent/agent-sdk-types.ts
@@ -255,8 +255,8 @@ export type ToolCallDetail =
     }
   | {
       type: "unknown";
-      input: unknown | null;
-      output: unknown | null;
+      input: unknown;
+      output: unknown;
     };
 
 interface ToolCallBase {
diff --git a/packages/server/src/server/agent/providers/claude-agent.integration.test.ts b/packages/server/src/server/agent/providers/claude-agent.integration.test.ts
index 8bc531dd8..a83db5367 100644
--- a/packages/server/src/server/agent/providers/claude-agent.integration.test.ts
+++ b/packages/server/src/server/agent/providers/claude-agent.integration.test.ts
@@ -136,7 +136,7 @@ function getLatestCompletedBashCall(events: AgentStreamEvent[]): ToolCallTimelin
 }
 
 function getInternalQuery(session: AgentSession): unknown {
-  return (session as AgentSession & { query?: unknown | null }).query ?? null;
+  return (session as AgentSession & { query?: unknown }).query ?? null;
 }
 
 async function createSession(params?: {
diff --git a/packages/server/src/server/agent/providers/claude/tool-call-mapper.ts b/packages/server/src/server/agent/providers/claude/tool-call-mapper.ts
index 7aef1ea80..5c79eb01e 100644
--- a/packages/server/src/server/agent/providers/claude/tool-call-mapper.ts
+++ b/packages/server/src/server/agent/providers/claude/tool-call-mapper.ts
@@ -100,7 +100,7 @@ function resolveDetailName(toolKind: ClaudeToolKind, name: string): string {
 function mapClaudeToolCall(
   params: MapperParams,
   status: ClaudeToolCallStatus,
-  error: unknown | null,
+  error: unknown,
 ): ToolCallTimelineItem | null {
   const parsed = ClaudeRawToolCallSchema.safeParse({ ...params, status, error });
   if (!parsed.success) {
diff --git a/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts b/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
index 2ac389ba9..776bea34f 100644
--- a/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
+++ b/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
@@ -31,10 +31,10 @@ const CodexRolloutToolCallParamsSchema = z
 interface CodexNormalizedToolCallEnvelope {
   callId: string;
   name: string;
-  input?: unknown | null;
-  output?: unknown | null;
+  input?: unknown;
+  output?: unknown;
   status?: ToolCallTimelineItem["status"];
-  error?: unknown | null;
+  error?: unknown;
   metadata?: Record<string, unknown>;
   cwd?: string | null;
 }
diff --git a/packages/server/src/server/agent/providers/pi-direct-agent.ts b/packages/server/src/server/agent/providers/pi-direct-agent.ts
index 4f58c480c..a07f3ada6 100644
--- a/packages/server/src/server/agent/providers/pi-direct-agent.ts
+++ b/packages/server/src/server/agent/providers/pi-direct-agent.ts
@@ -201,7 +201,7 @@ interface PiLsToolCall {
 interface PiUnknownToolCall {
   kind: "unknown";
   toolName: string;
-  args: unknown | null;
+  args: unknown;
 }
 
 type PiTrackedToolCall =
diff --git a/packages/server/src/utils/paseo-config-file.ts b/packages/server/src/utils/paseo-config-file.ts
index ac033804a..19cb0e80f 100644
--- a/packages/server/src/utils/paseo-config-file.ts
+++ b/packages/server/src/utils/paseo-config-file.ts
@@ -46,7 +46,7 @@ export function statPaseoConfigPath(repoRoot: string): PaseoConfigRevision | nul
   };
 }
 
-export function readPaseoConfigJson(repoRoot: string): unknown | null {
+export function readPaseoConfigJson(repoRoot: string): unknown {
   const configPath = resolvePaseoConfigPath(repoRoot);
   if (!existsSync(configPath)) {
     return null;