diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0bc1263a70a..9a24db2ead6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ Docs: https://docs.openclaw.ai
 - Codex app-server: stream commentary preambles into editable channel progress drafts without promoting them to final answers.
 - Codex migration: remove the bundled `codex-cli` backend and repair legacy `codex-cli/*` model refs to the Codex app-server route on `openai/*`.
 - Gateway/startup: add owner-level startup trace attribution for auth, plugin loading, lookup counts, and plugin sidecar services. (#81738) Thanks @samzong.
+- Plugins/hooks: expose the resolved effective `contextTokenBudget` plus source/reference metadata on `llm_output` and sanitized `model_call_*` hook events/contexts so plugin cost and context-health alerts can use agent-level context caps. Fixes #64327. Thanks @BunsDev.
 - Channels/status reactions: wire `StatusReactionController` into WhatsApp message turns (queued → thinking → tool → done/error lifecycle, on par with Telegram and Discord), add `deploy`/`build`/`concierge` emoji categories with tool-token routing, and replace the status reaction defaults with self-explanatory emoji (🧠 thinking, 🛠️ tool, 💻 coding, 🌐 web, ⏳ stallSoft, ⚠️ stallHard, ✅ done, ❌ error, 🗜️ compacting) so stall and lifecycle reactions read as status indicators instead of emotional commentary. Fixes #59077. (#80612) Thanks @gado-ships-it.
 - Control UI: add a browser-local Text size setting in Appearance and Quick Settings, scaling chat and dense UI text while keeping inputs above the mobile Safari focus-zoom threshold. Fixes #8547. Thanks @BunsDev.
 - Docs: add a dedicated ds4 provider page with local DeepSeek V4 Flash config, on-demand startup, context sizing, and live verification steps.
diff --git a/docs/plugins/hooks.md b/docs/plugins/hooks.md
index 05cf023583b..22a50f38d3f 100644
--- a/docs/plugins/hooks.md
+++ b/docs/plugins/hooks.md
@@ -114,7 +114,7 @@ observation-only.
 
 - `model_call_started` / `model_call_ended` - observe sanitized provider/model call metadata, timing, outcome, and bounded request-id hashes without prompt or response content
 - `llm_input` - observe provider input (system prompt, prompt, history)
-- `llm_output` - observe provider output
+- `llm_output` - observe provider output, usage, and the resolved `contextTokenBudget` when available
 
 **Tools**
 
@@ -287,7 +287,11 @@ that should not receive raw prompts, history, responses, headers, request
 bodies, or provider request IDs. These hooks include stable metadata such as
 `runId`, `callId`, `provider`, `model`, optional `api`/`transport`, terminal
 `durationMs`/`outcome`, and `upstreamRequestIdHash` when OpenClaw can derive a
-bounded provider request-id hash.
+bounded provider request-id hash. When the runtime has resolved context-window
+metadata, the hook event and context also include `contextTokenBudget`, the
+effective token budget after model/config/agent caps, plus
+`contextWindowSource` and `contextWindowReferenceTokens` when a lower cap was
+applied.
 
 `before_agent_finalize` runs only when a harness is about to accept a natural
 final assistant answer. It is not the `/stop` cancellation path and does not
diff --git a/extensions/codex/src/app-server/run-attempt.test.ts b/extensions/codex/src/app-server/run-attempt.test.ts
index 74cc777c90a..28e35b2b672 100644
--- a/extensions/codex/src/app-server/run-attempt.test.ts
+++ b/extensions/codex/src/app-server/run-attempt.test.ts
@@ -62,6 +62,12 @@ function createParams(sessionFile: string, workspaceDir: string): EmbeddedRunAtt
     provider: "codex",
     modelId: "gpt-5.4-codex",
     model: createCodexTestModel("codex"),
+    contextTokenBudget: 150_000,
+    contextWindowInfo: {
+      tokens: 150_000,
+      referenceTokens: 200_000,
+      source: "agentContextTokens",
+    },
     thinkLevel: "medium",
     disableTools: true,
     timeoutMs: 5_000,
@@ -2647,19 +2653,34 @@ describe("runCodexAppServerAttempt", () => {
         resolvedRef?: string;
         runId?: string;
         sessionId?: string;
+        contextTokenBudget?: number;
+        contextWindowSource?: string;
+        contextWindowReferenceTokens?: number;
+      },
+      {
+        runId?: string;
+        sessionId?: string;
+        contextTokenBudget?: number;
+        contextWindowSource?: string;
+        contextWindowReferenceTokens?: number;
       },
-      { runId?: string; sessionId?: string },
     ];
     expect(llmOutputPayload.runId).toBe("run-1");
     expect(llmOutputPayload.sessionId).toBe("session-1");
     expect(llmOutputPayload.provider).toBe("codex");
     expect(llmOutputPayload.model).toBe("gpt-5.4-codex");
+    expect(llmOutputPayload.contextTokenBudget).toBe(150_000);
+    expect(llmOutputPayload.contextWindowSource).toBe("agentContextTokens");
+    expect(llmOutputPayload.contextWindowReferenceTokens).toBe(200_000);
     expect(llmOutputPayload.resolvedRef).toBe("codex/gpt-5.4-codex");
     expect(llmOutputPayload.harnessId).toBe("codex");
     expect(llmOutputPayload.assistantTexts).toEqual(["hello back"]);
     expect(llmOutputPayload.lastAssistant?.role).toBe("assistant");
     expect(llmOutputContext.runId).toBe("run-1");
     expect(llmOutputContext.sessionId).toBe("session-1");
+    expect(llmOutputContext.contextTokenBudget).toBe(150_000);
+    expect(llmOutputContext.contextWindowSource).toBe("agentContextTokens");
+    expect(llmOutputContext.contextWindowReferenceTokens).toBe(200_000);
     const [agentEndPayload, agentEndContext] = mockCall(agentEnd, "agent_end") as [
       { messages?: Array<{ role?: string }>; success?: boolean },
       { runId?: string; sessionId?: string },
diff --git a/extensions/codex/src/app-server/run-attempt.ts b/extensions/codex/src/app-server/run-attempt.ts
index cfba40ee4f6..e43f91073a2 100644
--- a/extensions/codex/src/app-server/run-attempt.ts
+++ b/extensions/codex/src/app-server/run-attempt.ts
@@ -561,6 +561,19 @@ export async function runCodexAppServerAttempt(
   });
   const hadSessionFile = await pathExists(params.sessionFile);
   let historyMessages = (await readMirroredSessionHistoryMessages(params.sessionFile)) ?? [];
+  const hookContextWindowFields = {
+    ...(params.contextWindowInfo?.tokens
+      ? { contextTokenBudget: params.contextWindowInfo.tokens }
+      : params.contextTokenBudget
+        ? { contextTokenBudget: params.contextTokenBudget }
+        : {}),
+    ...(params.contextWindowInfo?.source
+      ? { contextWindowSource: params.contextWindowInfo.source }
+      : {}),
+    ...(params.contextWindowInfo?.referenceTokens
+      ? { contextWindowReferenceTokens: params.contextWindowInfo.referenceTokens }
+      : {}),
+  };
   const hookContext = {
     runId: params.runId,
     agentId: sessionAgentId,
@@ -570,6 +583,7 @@ export async function runCodexAppServerAttempt(
     messageProvider: params.messageProvider ?? undefined,
     trigger: params.trigger,
     channelId: params.messageChannel ?? params.messageProvider ?? undefined,
+    ...hookContextWindowFields,
   };
   if (activeContextEngine) {
     await bootstrapHarnessContextEngine({
@@ -1557,6 +1571,7 @@ export async function runCodexAppServerAttempt(
           sessionId: params.sessionId,
           provider: params.provider,
           model: params.modelId,
+          ...hookContextWindowFields,
           resolvedRef:
             params.runtimePlan?.observability.resolvedRef ?? `${params.provider}/${params.modelId}`,
           ...(params.runtimePlan?.observability.harnessId
@@ -1798,6 +1813,7 @@ export async function runCodexAppServerAttempt(
         sessionId: params.sessionId,
         provider: params.provider,
         model: params.modelId,
+        ...hookContextWindowFields,
         resolvedRef:
           params.runtimePlan?.observability.resolvedRef ?? `${params.provider}/${params.modelId}`,
         ...(params.runtimePlan?.observability.harnessId
diff --git a/src/agents/cli-runner.reliability.test.ts b/src/agents/cli-runner.reliability.test.ts
index eb23e5e20b7..3a104711e23 100644
--- a/src/agents/cli-runner.reliability.test.ts
+++ b/src/agents/cli-runner.reliability.test.ts
@@ -147,6 +147,11 @@ function buildPreparedContext(params?: {
     reusableCliSession: params?.cliSessionId ? { sessionId: params.cliSessionId } : {},
     modelId: "gpt-5.4",
     normalizedModel: "gpt-5.4",
+    contextWindowInfo: {
+      tokens: 150_000,
+      referenceTokens: 200_000,
+      source: "agentContextTokens",
+    },
     systemPrompt: "You are a helpful assistant.",
     systemPromptReport: {} as PreparedCliRunContext["systemPromptReport"],
     bootstrapPromptWarningLines: [],
@@ -665,13 +670,22 @@ describe("runCliAgent reliability", () => {
       expect(llmOutputEvent.sessionId).toBe("s1");
       expect(llmOutputEvent.provider).toBe("codex-cli");
       expect(llmOutputEvent.model).toBe("gpt-5.4");
+      expect(llmOutputEvent.contextTokenBudget).toBe(150_000);
+      expect(llmOutputEvent.contextWindowSource).toBe("agentContextTokens");
+      expect(llmOutputEvent.contextWindowReferenceTokens).toBe(200_000);
       expect(llmOutputEvent.assistantTexts).toEqual(["hello from cli"]);
       const lastAssistant = requireRecord(llmOutputEvent.lastAssistant, "last assistant");
       expect(lastAssistant.role).toBe("assistant");
       expect(lastAssistant.content).toEqual([{ type: "text", text: "hello from cli" }]);
       expect(lastAssistant.provider).toBe("codex-cli");
       expect(lastAssistant.model).toBe("gpt-5.4");
-      expect(callArg(hookRunner.runLlmOutput, 0, 1, "llm_output context")).toBeTypeOf("object");
+      const llmOutputContext = requireRecord(
+        callArg(hookRunner.runLlmOutput, 0, 1, "llm_output context"),
+        "llm_output context",
+      );
+      expect(llmOutputContext.contextTokenBudget).toBe(150_000);
+      expect(llmOutputContext.contextWindowSource).toBe("agentContextTokens");
+      expect(llmOutputContext.contextWindowReferenceTokens).toBe(200_000);
 
       const agentEndEvent = requireRecord(
         callArg(hookRunner.runAgentEnd, 0, 0, "agent_end event"),
diff --git a/src/agents/cli-runner.ts b/src/agents/cli-runner.ts
index dbbf29041e4..5b4842a7430 100644
--- a/src/agents/cli-runner.ts
+++ b/src/agents/cli-runner.ts
@@ -166,6 +166,15 @@ export async function runPreparedCliAgent(
     sessionId: params.sessionId,
     workspaceDir: params.workspaceDir,
     trigger: params.trigger,
+    ...(context.contextWindowInfo?.tokens
+      ? { contextTokenBudget: context.contextWindowInfo.tokens }
+      : {}),
+    ...(context.contextWindowInfo?.source
+      ? { contextWindowSource: context.contextWindowInfo.source }
+      : {}),
+    ...(context.contextWindowInfo?.referenceTokens
+      ? { contextWindowReferenceTokens: context.contextWindowInfo.referenceTokens }
+      : {}),
     ...buildAgentHookContextChannelFields(params),
   } as const;
 
@@ -308,6 +317,15 @@ export async function runPreparedCliAgent(
           sessionId: params.sessionId,
           provider: params.provider,
           model: context.modelId,
+          ...(context.contextWindowInfo?.tokens
+            ? { contextTokenBudget: context.contextWindowInfo.tokens }
+            : {}),
+          ...(context.contextWindowInfo?.source
+            ? { contextWindowSource: context.contextWindowInfo.source }
+            : {}),
+          ...(context.contextWindowInfo?.referenceTokens
+            ? { contextWindowReferenceTokens: context.contextWindowInfo.referenceTokens }
+            : {}),
           resolvedRef: `${params.provider}/${context.modelId}`,
           assistantTexts,
           ...(lastAssistant ? { lastAssistant } : {}),
diff --git a/src/agents/cli-runner/prepare.ts b/src/agents/cli-runner/prepare.ts
index d776ba66437..c2c5606051b 100644
--- a/src/agents/cli-runner/prepare.ts
+++ b/src/agents/cli-runner/prepare.ts
@@ -30,6 +30,8 @@ import { CLI_AUTH_EPOCH_VERSION, resolveCliAuthEpoch } from "../cli-auth-epoch.j
 import { resolveCliBackendConfig } from "../cli-backends.js";
 import { hashCliSessionText, resolveCliSessionReuse } from "../cli-session.js";
 import { claudeCliSessionTranscriptHasContent } from "../command/attempt-execution.helpers.js";
+import { resolveContextWindowInfo } from "../context-window-guard.js";
+import { DEFAULT_CONTEXT_TOKENS } from "../defaults.js";
 import { resolveHeartbeatPromptForSystemPrompt } from "../heartbeat-system-prompt.js";
 import {
   resolveBootstrapMaxChars,
@@ -156,6 +158,12 @@ export async function prepareCliRunContext(
   const modelId = (params.model ?? "default").trim() || "default";
   const normalizedModel = normalizeCliModel(modelId, backendResolved.config);
   const modelDisplay = `${params.provider}/${modelId}`;
+  const contextWindowInfo = resolveContextWindowInfo({
+    cfg: params.config,
+    provider: params.provider,
+    modelId,
+    defaultTokens: DEFAULT_CONTEXT_TOKENS,
+  });
 
   const sessionLabel = params.sessionKey ?? params.sessionId;
   const { bootstrapFiles, contextFiles } = await prepareDeps.resolveBootstrapContextForRun({
@@ -471,6 +479,7 @@ export async function prepareCliRunContext(
     reusableCliSession,
     modelId,
     normalizedModel,
+    contextWindowInfo,
     systemPrompt,
     systemPromptReport,
     bootstrapPromptWarningLines: bootstrapPromptWarning.lines,
diff --git a/src/agents/cli-runner/types.ts b/src/agents/cli-runner/types.ts
index b44ce951b11..15d35e4b8dc 100644
--- a/src/agents/cli-runner/types.ts
+++ b/src/agents/cli-runner/types.ts
@@ -10,6 +10,7 @@ import type { PromptImageOrderEntry } from "../../media/prompt-image-order.js";
 import type { InputProvenance } from "../../sessions/input-provenance.js";
 import type { BootstrapContextMode } from "../bootstrap-files.js";
 import type { ResolvedCliBackend } from "../cli-backends.js";
+import type { ContextWindowInfo } from "../context-window-guard.js";
 import type {
   CurrentTurnPromptContext,
   EmbeddedRunTrigger,
@@ -114,6 +115,7 @@ export type PreparedCliRunContext = {
   reusableCliSession: CliReusableSession;
   modelId: string;
   normalizedModel: string;
+  contextWindowInfo?: ContextWindowInfo;
   systemPrompt: string;
   systemPromptReport: SessionSystemPromptReport;
   bootstrapPromptWarningLines: string[];
diff --git a/src/agents/harness/hook-context.ts b/src/agents/harness/hook-context.ts
index 25a9bf19c9b..8d353a8eb9a 100644
--- a/src/agents/harness/hook-context.ts
+++ b/src/agents/harness/hook-context.ts
@@ -1,4 +1,7 @@
-import type { PluginHookAgentContext } from "../../plugins/hook-types.js";
+import type {
+  PluginHookAgentContext,
+  PluginHookContextWindowSource,
+} from "../../plugins/hook-types.js";
 
 export type AgentHarnessHookContext = {
   runId: string;
@@ -12,6 +15,9 @@ export type AgentHarnessHookContext = {
   messageProvider?: string;
   trigger?: string;
   channelId?: string;
+  contextTokenBudget?: number;
+  contextWindowSource?: PluginHookContextWindowSource;
+  contextWindowReferenceTokens?: number;
 };
 
 export function buildAgentHookContext(params: AgentHarnessHookContext): PluginHookAgentContext {
@@ -27,5 +33,10 @@ export function buildAgentHookContext(params: AgentHarnessHookContext): PluginHo
     ...(params.messageProvider ? { messageProvider: params.messageProvider } : {}),
     ...(params.trigger ? { trigger: params.trigger } : {}),
     ...(params.channelId ? { channelId: params.channelId } : {}),
+    ...(params.contextTokenBudget ? { contextTokenBudget: params.contextTokenBudget } : {}),
+    ...(params.contextWindowSource ? { contextWindowSource: params.contextWindowSource } : {}),
+    ...(params.contextWindowReferenceTokens
+      ? { contextWindowReferenceTokens: params.contextWindowReferenceTokens }
+      : {}),
   };
 }
diff --git a/src/agents/pi-embedded-runner/run.ts b/src/agents/pi-embedded-runner/run.ts
index 2d1bd074c9f..de33df550d5 100644
--- a/src/agents/pi-embedded-runner/run.ts
+++ b/src/agents/pi-embedded-runner/run.ts
@@ -1288,6 +1288,7 @@ export async function runEmbeddedPiAgent(
             allowGatewaySubagentBinding: params.allowGatewaySubagentBinding,
             contextEngine,
             contextTokenBudget: ctxInfo.tokens,
+            contextWindowInfo: ctxInfo,
             skillsSnapshot: params.skillsSnapshot,
             prompt,
             transcriptPrompt: params.transcriptPrompt,
diff --git a/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.test.ts b/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.test.ts
index 261f3ba3c80..1204cc49932 100644
--- a/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.test.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.test.ts
@@ -390,6 +390,9 @@ describe("wrapStreamFnWithDiagnosticModelCallEvents", () => {
         model: "gpt-5.4",
         api: "openai-responses",
         transport: "http",
+        contextTokenBudget: 150_000,
+        contextWindowSource: "agentContextTokens",
+        contextWindowReferenceTokens: 200_000,
         trace: createDiagnosticTraceContext(),
         nextCallId: () => "call-hook",
       },
@@ -413,16 +416,25 @@ describe("wrapStreamFnWithDiagnosticModelCallEvents", () => {
     expect(startedEvent.model).toBe("gpt-5.4");
     expect(startedEvent.api).toBe("openai-responses");
     expect(startedEvent.transport).toBe("http");
+    expect(startedEvent.contextTokenBudget).toBe(150_000);
+    expect(startedEvent.contextWindowSource).toBe("agentContextTokens");
+    expect(startedEvent.contextWindowReferenceTokens).toBe(200_000);
     const startedCtx = requireMockRecordArg(started, 0, 1, "started hook context");
     expect(startedCtx.runId).toBe("run-1");
     expect(startedCtx.sessionKey).toBe("session-key");
     expect(startedCtx.sessionId).toBe("session-id");
     expect(startedCtx.modelProviderId).toBe("openai");
     expect(startedCtx.modelId).toBe("gpt-5.4");
+    expect(startedCtx.contextTokenBudget).toBe(150_000);
+    expect(startedCtx.contextWindowSource).toBe("agentContextTokens");
+    expect(startedCtx.contextWindowReferenceTokens).toBe(200_000);
     const endedEvent = requireMockRecordArg(ended, 0, 0, "ended hook event");
     expect(endedEvent.runId).toBe("run-1");
     expect(endedEvent.callId).toBe("call-hook");
     expect(endedEvent.outcome).toBe("completed");
+    expect(endedEvent.contextTokenBudget).toBe(150_000);
+    expect(endedEvent.contextWindowSource).toBe("agentContextTokens");
+    expect(endedEvent.contextWindowReferenceTokens).toBe(200_000);
     expectNumberField(endedEvent, "durationMs");
     expectNumberField(endedEvent, "responseStreamBytes");
     expectNumberField(endedEvent, "timeToFirstByteMs");
diff --git a/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.ts b/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.ts
index 1a1fbf0a550..88ca6d66217 100644
--- a/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.model-diagnostic-events.ts
@@ -19,6 +19,7 @@ import {
 import { getGlobalHookRunner } from "../../../plugins/hook-runner-global.js";
 import type {
   PluginHookAgentContext,
+  PluginHookContextWindowSource,
   PluginHookModelCallEndedEvent,
   PluginHookModelCallStartedEvent,
 } from "../../../plugins/hook-types.js";
@@ -33,6 +34,9 @@ type ModelCallDiagnosticContext = {
   model: string;
   api?: string;
   transport?: string;
+  contextTokenBudget?: number;
+  contextWindowSource?: PluginHookContextWindowSource;
+  contextWindowReferenceTokens?: number;
   trace: DiagnosticTraceContext;
   nextCallId: () => string;
   onStarted?: () => void;
@@ -150,6 +154,11 @@ function baseModelCallEvent(
     model: ctx.model,
     ...(ctx.api && { api: ctx.api }),
     ...(ctx.transport && { transport: ctx.transport }),
+    ...(ctx.contextTokenBudget ? { contextTokenBudget: ctx.contextTokenBudget } : {}),
+    ...(ctx.contextWindowSource ? { contextWindowSource: ctx.contextWindowSource } : {}),
+    ...(ctx.contextWindowReferenceTokens
+      ? { contextWindowReferenceTokens: ctx.contextWindowReferenceTokens }
+      : {}),
     trace,
   };
 }
@@ -189,6 +198,13 @@ function modelCallHookEventBase(eventBase: ModelCallEventBase): PluginHookModelC
     model: eventBase.model,
     ...(eventBase.api ? { api: eventBase.api } : {}),
     ...(eventBase.transport ? { transport: eventBase.transport } : {}),
+    ...(eventBase.contextTokenBudget ? { contextTokenBudget: eventBase.contextTokenBudget } : {}),
+    ...(eventBase.contextWindowSource
+      ? { contextWindowSource: eventBase.contextWindowSource }
+      : {}),
+    ...(eventBase.contextWindowReferenceTokens
+      ? { contextWindowReferenceTokens: eventBase.contextWindowReferenceTokens }
+      : {}),
   };
 }
 
@@ -200,6 +216,13 @@ function modelCallHookContext(eventBase: ModelCallEventBase): PluginHookAgentCon
     ...(eventBase.sessionId ? { sessionId: eventBase.sessionId } : {}),
     modelProviderId: eventBase.provider,
     modelId: eventBase.model,
+    ...(eventBase.contextTokenBudget ? { contextTokenBudget: eventBase.contextTokenBudget } : {}),
+    ...(eventBase.contextWindowSource
+      ? { contextWindowSource: eventBase.contextWindowSource }
+      : {}),
+    ...(eventBase.contextWindowReferenceTokens
+      ? { contextWindowReferenceTokens: eventBase.contextWindowReferenceTokens }
+      : {}),
   }) as PluginHookAgentContext;
 }
 
diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index bc741295de1..5f8d495709c 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -2447,6 +2447,15 @@ export async function runEmbeddedAttempt(
           model: params.modelId,
           api: params.model.api,
           transport: effectiveAgentTransport,
+          ...(params.contextWindowInfo?.tokens
+            ? { contextTokenBudget: params.contextWindowInfo.tokens }
+            : {}),
+          ...(params.contextWindowInfo?.source
+            ? { contextWindowSource: params.contextWindowInfo.source }
+            : {}),
+          ...(params.contextWindowInfo?.referenceTokens
+            ? { contextWindowReferenceTokens: params.contextWindowInfo.referenceTokens }
+            : {}),
           trace: runTrace,
           nextCallId: () => `${params.runId}:model:${(diagnosticModelCallSeq += 1)}`,
           onStarted: () => {
@@ -4006,6 +4015,15 @@ export async function runEmbeddedAttempt(
               sessionId: params.sessionId,
               provider: params.provider,
               model: params.modelId,
+              ...(params.contextWindowInfo?.tokens
+                ? { contextTokenBudget: params.contextWindowInfo.tokens }
+                : {}),
+              ...(params.contextWindowInfo?.source
+                ? { contextWindowSource: params.contextWindowInfo.source }
+                : {}),
+              ...(params.contextWindowInfo?.referenceTokens
+                ? { contextWindowReferenceTokens: params.contextWindowInfo.referenceTokens }
+                : {}),
               resolvedRef:
                 params.runtimePlan?.observability.resolvedRef ??
                 `${params.provider}/${params.modelId}`,
@@ -4024,6 +4042,15 @@ export async function runEmbeddedAttempt(
               sessionId: params.sessionId,
               workspaceDir: params.workspaceDir,
               trigger: params.trigger,
+              ...(params.contextWindowInfo?.tokens
+                ? { contextTokenBudget: params.contextWindowInfo.tokens }
+                : {}),
+              ...(params.contextWindowInfo?.source
+                ? { contextWindowSource: params.contextWindowInfo.source }
+                : {}),
+              ...(params.contextWindowInfo?.referenceTokens
+                ? { contextWindowReferenceTokens: params.contextWindowInfo.referenceTokens }
+                : {}),
               ...buildAgentHookContextChannelFields(params),
             },
           )
diff --git a/src/agents/pi-embedded-runner/run/types.ts b/src/agents/pi-embedded-runner/run/types.ts
index b0c13cccf83..5517d444abb 100644
--- a/src/agents/pi-embedded-runner/run/types.ts
+++ b/src/agents/pi-embedded-runner/run/types.ts
@@ -26,12 +26,20 @@ type EmbeddedRunAttemptBase = Omit<
   "provider" | "model" | "authProfileId" | "authProfileIdSource" | "thinkLevel" | "lane" | "enqueue"
 >;
 
+export type EmbeddedRunContextWindowInfo = {
+  tokens: number;
+  referenceTokens?: number;
+  source: "model" | "modelsConfig" | "agentContextTokens" | "default";
+};
+
 export type EmbeddedRunAttemptParams = EmbeddedRunAttemptBase & {
   initialReplayState?: EmbeddedRunReplayState;
   /** Pluggable context engine for ingest/assemble/compact lifecycle. */
   contextEngine?: ContextEngine;
   /** Resolved model context window in tokens for assemble/compact budgeting. */
   contextTokenBudget?: number;
+  /** Source metadata for the resolved model context budget. */
+  contextWindowInfo?: EmbeddedRunContextWindowInfo;
   /** Resolved API key for this run when runtime auth did not replace it. */
   resolvedApiKey?: string;
   /** Auth profile resolved for this attempt's provider/model call. */
diff --git a/src/infra/diagnostic-events.ts b/src/infra/diagnostic-events.ts
index 7dffb5001ac..b35f16b5997 100644
--- a/src/infra/diagnostic-events.ts
+++ b/src/infra/diagnostic-events.ts
@@ -458,6 +458,9 @@ type DiagnosticModelCallBaseEvent = DiagnosticBaseEvent & {
   model: string;
   api?: string;
   transport?: string;
+  contextTokenBudget?: number;
+  contextWindowSource?: "model" | "modelsConfig" | "agentContextTokens" | "default";
+  contextWindowReferenceTokens?: number;
   upstreamRequestIdHash?: string;
 };
 
diff --git a/src/plugins/hook-types.ts b/src/plugins/hook-types.ts
index 0d5fca1e1c1..58aec3e3080 100644
--- a/src/plugins/hook-types.ts
+++ b/src/plugins/hook-types.ts
@@ -196,8 +196,20 @@ export type PluginHookAgentContext = {
   messageProvider?: string;
   trigger?: string;
   channelId?: string;
+  /** Resolved effective context-token budget after model/config/agent caps. */
+  contextTokenBudget?: number;
+  /** Source that supplied the resolved context-token budget. */
+  contextWindowSource?: PluginHookContextWindowSource;
+  /** Native/configured reference window when a lower cap wins. */
+  contextWindowReferenceTokens?: number;
 };
 
+export type PluginHookContextWindowSource =
+  | "model"
+  | "modelsConfig"
+  | "agentContextTokens"
+  | "default";
+
 export type PluginHookBeforeAgentReplyEvent = {
   cleanedBody: string;
 };
@@ -229,6 +241,12 @@ export type PluginHookModelCallBaseEvent = {
   model: string;
   api?: string;
   transport?: string;
+  /** Resolved effective context-token budget after model/config/agent caps. */
+  contextTokenBudget?: number;
+  /** Source that supplied the resolved context-token budget. */
+  contextWindowSource?: PluginHookContextWindowSource;
+  /** Native/configured reference window when a lower cap wins. */
+  contextWindowReferenceTokens?: number;
 };
 
 export type PluginHookModelCallStartedEvent = PluginHookModelCallBaseEvent;
@@ -249,6 +267,12 @@ export type PluginHookLlmOutputEvent = {
   sessionId: string;
   provider: string;
   model: string;
+  /** Resolved effective context-token budget after model/config/agent caps. */
+  contextTokenBudget?: number;
+  /** Source that supplied the resolved context-token budget. */
+  contextWindowSource?: PluginHookContextWindowSource;
+  /** Native/configured reference window when a lower cap wins. */
+  contextWindowReferenceTokens?: number;
   /**
    * Fully resolved provider/model ref used for the call.
    *