feat: add /context prompt breakdown

src/agents/pi-embedded-runner/run.ts

@@ -250,6 +250,7 @@ export async function runEmbeddedPiAgent(
                     provider,
                     model: model.id,
                   },
+                  systemPromptReport: attempt.systemPromptReport,
                   error: { kind, message: errorText },
                 },
               };
@@ -404,6 +405,7 @@ export async function runEmbeddedPiAgent(
               durationMs: Date.now() - started,
               agentMeta,
               aborted,
+              systemPromptReport: attempt.systemPromptReport,
             },
             didSendViaMessagingTool: attempt.didSendViaMessagingTool,
             messagingToolSentTexts: attempt.messagingToolSentTexts,

src/agents/pi-embedded-runner/run/attempt.ts

@@ -37,6 +37,7 @@ import {
   loadWorkspaceSkillEntries,
   resolveSkillsPromptForRun,
 } from "../../skills.js";
+import { buildSystemPromptReport } from "../../system-prompt-report.js";
 import { filterBootstrapFilesForSession, loadWorkspaceBootstrapFiles } from "../../workspace.js";
 
 import { isAbortError } from "../abort.js";
@@ -62,6 +63,7 @@ import {
   resolveExecToolDefaults,
   resolveUserTimezone,
 } from "../utils.js";
+import { resolveSandboxRuntimeStatus } from "../../sandbox/runtime-status.js";
 
 import type { EmbeddedRunAttemptParams, EmbeddedRunAttemptResult } from "./types.js";
 
@@ -198,6 +200,28 @@ export async function runEmbeddedAttempt(
       userTime,
       contextFiles,
     });
+    const systemPromptReport = buildSystemPromptReport({
+      source: "run",
+      generatedAt: Date.now(),
+      sessionId: params.sessionId,
+      sessionKey: params.sessionKey,
+      provider: params.provider,
+      model: params.modelId,
+      workspaceDir: effectiveWorkspace,
+      bootstrapMaxChars: resolveBootstrapMaxChars(params.config),
+      sandbox: (() => {
+        const runtime = resolveSandboxRuntimeStatus({
+          cfg: params.config,
+          sessionKey: params.sessionKey ?? params.sessionId,
+        });
+        return { mode: runtime.mode, sandboxed: runtime.sandboxed };
+      })(),
+      systemPrompt: appendPrompt,
+      bootstrapFiles,
+      injectedFiles: contextFiles,
+      skillsPrompt,
+      tools,
+    });
     const systemPrompt = createSystemPromptOverride(appendPrompt);
 
     const sessionLock = await acquireSessionWriteLock({
@@ -427,6 +451,7 @@ export async function runEmbeddedAttempt(
         timedOut,
         promptError,
         sessionIdUsed,
+        systemPromptReport,
         messagesSnapshot,
         assistantTexts,
         toolMetas: toolMetasNormalized,

src/agents/pi-embedded-runner/run/types.ts

@@ -8,6 +8,7 @@ import type { ExecElevatedDefaults } from "../../bash-tools.js";
 import type { MessagingToolSend } from "../../pi-embedded-messaging.js";
 import type { BlockReplyChunking } from "../../pi-embedded-subscribe.js";
 import type { SkillSnapshot } from "../../skills.js";
+import type { SessionSystemPromptReport } from "../../../config/sessions/types.js";
 
 type AuthStorage = ReturnType<typeof discoverAuthStorage>;
 type ModelRegistry = ReturnType<typeof discoverModels>;
@@ -65,6 +66,7 @@ export type EmbeddedRunAttemptResult = {
   timedOut: boolean;
   promptError: unknown;
   sessionIdUsed: string;
+  systemPromptReport?: SessionSystemPromptReport;
   messagesSnapshot: AgentMessage[];
   assistantTexts: string[];
   toolMetas: Array<{ toolName: string; meta?: string }>;

src/agents/pi-embedded-runner/types.ts

@@ -1,4 +1,5 @@
 import type { MessagingToolSend } from "../pi-embedded-messaging.js";
+import type { SessionSystemPromptReport } from "../../config/sessions/types.js";
 
 export type EmbeddedPiAgentMeta = {
   sessionId: string;
@@ -17,6 +18,7 @@ export type EmbeddedPiRunMeta = {
   durationMs: number;
   agentMeta?: EmbeddedPiAgentMeta;
   aborted?: boolean;
+  systemPromptReport?: SessionSystemPromptReport;
   error?: {
     kind: "context_overflow" | "compaction_failure";
     message: string;