diff --git a/src/agents/model-auth-label.ts b/src/agents/model-auth-label.ts
index 26458c71e0a4..a7cd40e36e15 100644
--- a/src/agents/model-auth-label.ts
+++ b/src/agents/model-auth-label.ts
@@ -20,6 +20,10 @@ import {
 } from "./model-auth.js";
 import { normalizeProviderId } from "./model-selection.js";
 
+// Builds concise auth labels for UI/status surfaces without exposing credential
+// values. Resolution follows profile override, provider profiles, env, CLI, then
+// custom provider config.
+/** Resolve the display label that describes how a provider is authenticated. */
 export function resolveModelAuthLabel(params: {
   provider?: string;
   cfg?: OpenClawConfig;
@@ -106,6 +110,8 @@ export function resolveModelAuthLabel(params: {
     return `api-key${label ? ` (${label})` : ""}`;
   }
   if (providerEntryProfileRef.kind === "profile-incompatible") {
+    // Preserve the fact that config pointed at a profile while avoiding a
+    // misleading auth mode for an incompatible provider/profile pairing.
     return "unknown";
   }
 
diff --git a/src/agents/model-auth-runtime-shared.ts b/src/agents/model-auth-runtime-shared.ts
index 613e5144dd02..a9f80c48f6db 100644
--- a/src/agents/model-auth-runtime-shared.ts
+++ b/src/agents/model-auth-runtime-shared.ts
@@ -1,5 +1,7 @@
 import { normalizeSecretInput } from "../utils/normalize-secret-input.js";
 
+// Shared provider-auth runtime types and errors. Provider calls use these helpers
+// to fail with actionable auth provenance while keeping secret normalization local.
 const AWS_BEARER_ENV = "AWS_BEARER_TOKEN_BEDROCK";
 const AWS_ACCESS_KEY_ENV = "AWS_ACCESS_KEY_ID";
 const AWS_SECRET_KEY_ENV = "AWS_SECRET_ACCESS_KEY";
@@ -14,6 +16,7 @@ export type ResolvedProviderAuth = {
 
 export type ProviderAuthErrorCode = "missing-api-key" | "missing-provider-auth";
 
+/** Base provider auth error with a stable code for retry/fallback logic. */
 export class ProviderAuthError extends Error {
   readonly code: ProviderAuthErrorCode;
   readonly provider: string;
@@ -26,6 +29,7 @@ export class ProviderAuthError extends Error {
   }
 }
 
+/** Auth error raised when a resolved provider auth source lacks usable material. */
 export class MissingProviderAuthError extends ProviderAuthError {
   readonly mode: ResolvedProviderAuth["mode"];
   readonly source: string;
@@ -38,6 +42,7 @@ export class MissingProviderAuthError extends ProviderAuthError {
   }
 }
 
+/** Narrow unknown errors to provider auth errors, optionally by code. */
 export function isProviderAuthError(
   err: unknown,
   code?: ProviderAuthErrorCode,
@@ -45,10 +50,12 @@ export function isProviderAuthError(
   return err instanceof ProviderAuthError && (!code || err.code === code);
 }
 
+/** Narrow unknown errors to missing-provider-auth failures. */
 export function isMissingProviderAuthError(err: unknown): err is MissingProviderAuthError {
   return err instanceof MissingProviderAuthError;
 }
 
+/** Return the AWS credential env var that proves SDK auth is configured. */
 export function resolveAwsSdkEnvVarName(env: NodeJS.ProcessEnv = process.env): string | undefined {
   if (env[AWS_BEARER_ENV]?.trim()) {
     return AWS_BEARER_ENV;
@@ -62,10 +69,12 @@ export function resolveAwsSdkEnvVarName(env: NodeJS.ProcessEnv = process.env): s
   return undefined;
 }
 
+/** Format the user-facing missing-auth error from auth provenance. */
 export function formatMissingAuthError(auth: ResolvedProviderAuth, provider: string): string {
   return `No API key resolved for provider "${provider}" (auth mode: ${auth.mode}, checked: ${auth.source}).`;
 }
 
+/** Require a normalized API key or throw a provider-auth error. */
 export function requireApiKey(auth: ResolvedProviderAuth, provider: string): string {
   const key = normalizeSecretInput(auth.apiKey);
   if (key) {
diff --git a/src/agents/model-fallback-observation.ts b/src/agents/model-fallback-observation.ts
index f5173fd854a3..77ea0a1438b7 100644
--- a/src/agents/model-fallback-observation.ts
+++ b/src/agents/model-fallback-observation.ts
@@ -4,8 +4,11 @@ import { buildTextObservationFields } from "./embedded-agent-error-observation.j
 import type { FailoverReason } from "./embedded-agent-helpers.js";
 import type { FallbackAttempt, ModelCandidate } from "./model-fallback.types.js";
 
+// Structured logging for model fallback decisions. The log payload carries
+// sanitized error observations plus step fields that make fallback chains auditable.
 const decisionLog = createSubsystemLogger("model-fallback").child("decision");
 
+/** Return whether fallback decision logging is enabled for warn-level events. */
 export function isModelFallbackDecisionLogEnabled(): boolean {
   return decisionLog.isEnabled("warn");
 }
@@ -85,6 +88,8 @@ function buildFallbackStepFields(params: {
 }): ModelFallbackStepFields | undefined {
   const lastPreviousAttempt = params.previousAttempts?.at(-1);
   if (params.decision === "candidate_succeeded") {
+    // Success records the previous failed candidate as the source and the current
+    // candidate as the successful fallback destination.
     if (!lastPreviousAttempt) {
       return undefined;
     }
@@ -120,6 +125,7 @@ function buildFallbackStepFields(params: {
   };
 }
 
+/** Log one model fallback decision and return structured fallback-step fields. */
 export function logModelFallbackDecision(
   params: ModelFallbackDecisionParams,
 ): ModelFallbackStepFields | undefined {
diff --git a/src/agents/tool-allowlist-guard.ts b/src/agents/tool-allowlist-guard.ts
index d6ea2ae801a8..0af251a1ec27 100644
--- a/src/agents/tool-allowlist-guard.ts
+++ b/src/agents/tool-allowlist-guard.ts
@@ -1,12 +1,15 @@
 import { normalizeStringEntries } from "@openclaw/normalization-core/string-normalization";
 import { normalizeToolList, normalizeToolName } from "./tool-policy.js";
 
+// Guardrails for explicit tool allowlists. They collect user/operator sources and
+// explain when allowlist resolution leaves no callable tools.
 type ExplicitToolAllowlistSource = {
   label: string;
   entries: string[];
   enforceWhenToolsDisabled?: boolean;
 };
 
+/** Normalize explicit allowlist sources, dropping empty source entries. */
 export function collectExplicitToolAllowlistSources(
   sources: Array<{ label: string; allow?: string[]; enforceWhenToolsDisabled?: boolean }>,
 ): ExplicitToolAllowlistSource[] {
@@ -25,6 +28,7 @@ export function collectExplicitToolAllowlistSources(
   });
 }
 
+/** Build an actionable error when explicit allowlists remove every callable tool. */
 export function buildEmptyExplicitToolAllowlistError(params: {
   sources: ExplicitToolAllowlistSource[];
   callableToolNames: string[];
diff --git a/src/agents/trace-base.ts b/src/agents/trace-base.ts
index d19b24743118..47671cfe5dbe 100644
--- a/src/agents/trace-base.ts
+++ b/src/agents/trace-base.ts
@@ -1,3 +1,4 @@
+// Common trace fields copied into provider/model diagnostic events.
 type AgentTraceBase = {
   runId?: string;
   sessionId?: string;
@@ -8,6 +9,7 @@ type AgentTraceBase = {
   workspaceDir?: string;
 };
 
+/** Build a trace base object while preserving undefined optional fields. */
 export function buildAgentTraceBase(params: AgentTraceBase): AgentTraceBase {
   return {
     runId: params.runId,
diff --git a/src/agents/transcript-redact.ts b/src/agents/transcript-redact.ts
index 119ee6a40bb5..f74f774ea190 100644
--- a/src/agents/transcript-redact.ts
+++ b/src/agents/transcript-redact.ts
@@ -7,6 +7,9 @@ import {
 } from "../logging/redact.js";
 import type { AgentMessage } from "./runtime/index.js";
 
+// Transcript redaction helpers for persisted agent messages. Text and structured
+// fields share logging redaction config while preserving object identity when no
+// redaction changes are needed.
 function resolveTranscriptRedactPatterns(patterns?: string[]) {
   return patterns && patterns.length > 0 ? [...patterns, ...getDefaultRedactPatterns()] : undefined;
 }
@@ -79,9 +82,13 @@ function redactTranscriptStructuredValue(
     return value;
   }
   if (seen.has(value)) {
+    // Avoid recursive transcript payloads from escaping redaction or crashing
+    // persistence; circular refs serialize as a stable marker.
     return "[Circular]";
   }
   if (!isPlainTranscriptObject(value)) {
+    // Non-plain instances can carry runtime state; leave them untouched instead
+    // of cloning unexpected prototypes into transcripts.
     return value;
   }
 
@@ -100,6 +107,7 @@ function redactTranscriptStructuredValue(
   return next ?? value;
 }
 
+/** Return a redacted transcript message according to logging config. */
 export function redactTranscriptMessage(message: AgentMessage, cfg?: OpenClawConfig): AgentMessage {
   if (cfg?.logging?.redactSensitive === "off") {
     return message;