Move exec to HookAPI, sessionManager/modelRegistry to HookEventContext

Breaking changes:
- HookEventContext now has sessionManager and modelRegistry (moved from SessionEventBase)
- HookAPI now has exec() method (moved from HookEventContext/HookCommandContext)
- HookRunner constructor takes sessionManager and modelRegistry as required params
- Session events no longer include sessionManager/modelRegistry fields

Hook code migration:
- event.sessionManager -> ctx.sessionManager
- event.modelRegistry -> ctx.modelRegistry
- ctx.exec() -> pi.exec()

Updated:
- src/core/hooks/types.ts - type changes
- src/core/hooks/runner.ts - constructor, createContext
- src/core/hooks/loader.ts - add exec to HookAPI
- src/core/sdk.ts - pass sessionManager/modelRegistry to HookRunner
- src/core/agent-session.ts - remove sessionManager/modelRegistry from events
- src/modes/* - remove setSessionFile calls, update events
- examples/hooks/* - update to new API

packages/coding-agent/examples/hooks/auto-commit-on-exit.ts

@@ -12,7 +12,7 @@ export default function (pi: HookAPI) {
 		if (event.reason !== "shutdown") return;
 
 		// Check for uncommitted changes
-		const { stdout: status, code } = await ctx.exec("git", ["status", "--porcelain"]);
+		const { stdout: status, code } = await pi.exec("git", ["status", "--porcelain"]);
 
 		if (code !== 0 || status.trim().length === 0) {
 			// Not a git repo or no changes
@@ -20,7 +20,7 @@ export default function (pi: HookAPI) {
 		}
 
 		// Find the last assistant message for commit context
-		const entries = event.sessionManager.getEntries();
+		const entries = ctx.sessionManager.getEntries();
 		let lastAssistantText = "";
 		for (let i = entries.length - 1; i >= 0; i--) {
 			const entry = entries[i];
@@ -41,8 +41,8 @@ export default function (pi: HookAPI) {
 		const commitMessage = `[pi] ${firstLine.slice(0, 50)}${firstLine.length > 50 ? "..." : ""}`;
 
 		// Stage and commit
-		await ctx.exec("git", ["add", "-A"]);
-		const { code: commitCode } = await ctx.exec("git", ["commit", "-m", commitMessage]);
+		await pi.exec("git", ["add", "-A"]);
+		const { code: commitCode } = await pi.exec("git", ["commit", "-m", commitMessage]);
 
 		if (commitCode === 0 && ctx.hasUI) {
 			ctx.ui.notify(`Auto-committed: ${commitMessage}`, "info");

packages/coding-agent/examples/hooks/confirm-destructive.ts

@@ -29,7 +29,7 @@ export default function (pi: HookAPI) {
 			if (!ctx.hasUI) return;
 
 			// Check if there are unsaved changes (messages since last assistant response)
-			const entries = event.sessionManager.getEntries();
+			const entries = ctx.sessionManager.getEntries();
 			const hasUnsavedWork = entries.some(
 				(e): e is SessionMessageEntry => e.type === "message" && e.message.role === "user",
 			);

packages/coding-agent/examples/hooks/custom-compaction.ts

@@ -23,7 +23,7 @@ export default function (pi: HookAPI) {
 
 		ctx.ui.notify("Custom compaction hook triggered", "info");
 
-		const { preparation, previousCompactions, modelRegistry, signal } = event;
+		const { preparation, previousCompactions, signal } = event;
 		const { messagesToSummarize, messagesToKeep, tokensBefore, firstKeptEntryId } = preparation;
 
 		// Get previous summary from most recent compaction (if any)
@@ -37,7 +37,7 @@ export default function (pi: HookAPI) {
 		}
 
 		// Resolve API key for the summarization model
-		const apiKey = await modelRegistry.getApiKey(model);
+		const apiKey = await ctx.modelRegistry.getApiKey(model);
 		if (!apiKey) {
 			ctx.ui.notify(`No API key for ${model.provider}, using default compaction`, "warning");
 			return;

packages/coding-agent/examples/hooks/dirty-repo-guard.ts

@@ -15,7 +15,7 @@ export default function (pi: HookAPI) {
 		}
 
 		// Check for uncommitted changes
-		const { stdout, code } = await ctx.exec("git", ["status", "--porcelain"]);
+		const { stdout, code } = await pi.exec("git", ["status", "--porcelain"]);
 
 		if (code !== 0) {
 			// Not a git repo, allow the action

packages/coding-agent/examples/hooks/git-checkpoint.ts

@@ -10,9 +10,9 @@ import type { HookAPI } from "@mariozechner/pi-coding-agent/hooks";
 export default function (pi: HookAPI) {
 	const checkpoints = new Map<number, string>();
 
-	pi.on("turn_start", async (event, ctx) => {
+	pi.on("turn_start", async (event) => {
 		// Create a git stash entry before LLM makes changes
-		const { stdout } = await ctx.exec("git", ["stash", "create"]);
+		const { stdout } = await pi.exec("git", ["stash", "create"]);
 		const ref = stdout.trim();
 		if (ref) {
 			checkpoints.set(event.turnIndex, ref);
@@ -37,7 +37,7 @@ export default function (pi: HookAPI) {
 		]);
 
 		if (choice?.startsWith("Yes")) {
-			await ctx.exec("git", ["stash", "apply", ref]);
+			await pi.exec("git", ["stash", "apply", ref]);
 			ctx.ui.notify("Code restored to checkpoint", "info");
 		}
 	});