Phase 10: rescan branch for tracked skills when state entry missing — SPEC §6.3.

Walk user messages and read tool calls on session_start to rebuild tracked
skills from history when no skill-reinject:state entry exists on the branch.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/index.ts

@@ -22,6 +22,7 @@ import {
 	tryConsumeDeferredReinject,
 } from "./reinject.js";
 import { readSettings } from "./settings.js";
+import { rescanSkillsFromBranch } from "./rescan.js";
 import { findRegisteredSkillByName, resolveRegisteredSkills } from "./skills-registry.js";
 import {
 	applyExtensionState,
@@ -99,9 +100,13 @@ export default function skillReinject(pi: ExtensionAPI): void {
 
 	pi.on("session_start", async (_event, ctx) => {
 		detectAndCachePiAutoCompact(pi, runtime);
-		readSettings(ctx);
-		const loaded = loadStateFromBranch(ctx.sessionManager.getBranch());
+		const settings = readSettings(ctx);
+		const branch = ctx.sessionManager.getBranch();
+		const loaded = loadStateFromBranch(branch);
 		applyExtensionState(state, loaded ?? createInitialState());
+		if (!loaded) {
+			rescanSkillsFromBranch(state, branch, ctx.cwd, registeredSkills, settings.trackReadPaths);
+		}
 	});
 
 	pi.on("session_before_compact", async () => {

src/rescan.ts

@@ -0,0 +1,99 @@
+import { dirname } from "node:path";
+import type { SessionEntry, Skill } from "@earendil-works/pi-coding-agent";
+import {
+	detectSlashSkill,
+	matchReadPathToSkillWhenEnabled,
+	parseSkillBlocksFromText,
+	userMessageText,
+} from "./detect.js";
+import { findRegisteredSkillByName, resolveRegisteredSkills } from "./skills-registry.js";
+import { trackSkill, type ExtensionState } from "./state.js";
+
+function entrySeenAt(entry: SessionEntry): number {
+	const ts = Date.parse(entry.timestamp);
+	return Number.isFinite(ts) ? ts : Date.now();
+}
+
+function readPathsFromContent(content: unknown): string[] {
+	if (!Array.isArray(content)) {
+		return [];
+	}
+	const paths: string[] = [];
+	for (const part of content) {
+		if (!part || typeof part !== "object") {
+			continue;
+		}
+		const block = part as { type?: string; name?: string; arguments?: Record<string, unknown> };
+		if (block.type !== "toolCall" || block.name !== "read") {
+			continue;
+		}
+		const path = block.arguments?.path;
+		if (typeof path === "string") {
+			paths.push(path);
+		}
+	}
+	return paths;
+}
+
+/** Full branch rescan when no persisted state entry exists (SPEC §6.3). */
+export function rescanSkillsFromBranch(
+	state: ExtensionState,
+	branch: SessionEntry[],
+	cwd: string,
+	registeredSkills: readonly Skill[],
+	trackReadPaths: boolean,
+): void {
+	const skills = resolveRegisteredSkills(cwd, registeredSkills);
+
+	for (const entry of branch) {
+		if (entry.type !== "message") {
+			continue;
+		}
+		const { message } = entry;
+		const seenAt = entrySeenAt(entry);
+
+		if (message.role === "user") {
+			const text = userMessageText(message.content);
+
+			const slashName = detectSlashSkill(text);
+			if (slashName) {
+				const skill = findRegisteredSkillByName(skills, slashName);
+				if (skill) {
+					trackSkill(state, {
+						name: skill.name,
+						filePath: skill.filePath,
+						baseDir: skill.baseDir,
+						source: "slash",
+						seenAt,
+					});
+				}
+			}
+
+			for (const block of parseSkillBlocksFromText(text)) {
+				const registered = findRegisteredSkillByName(skills, block.name);
+				trackSkill(state, {
+					name: block.name,
+					filePath: registered?.filePath ?? block.location,
+					baseDir: registered?.baseDir ?? dirname(block.location),
+					source: "skill-block",
+					seenAt,
+				});
+			}
+		}
+
+		if (message.role === "assistant") {
+			for (const path of readPathsFromContent(message.content)) {
+				const matched = matchReadPathToSkillWhenEnabled(path, skills, trackReadPaths);
+				if (matched) {
+					trackSkill(state, {
+						name: matched.name,
+						filePath: matched.filePath,
+						baseDir: matched.baseDir,
+						source: "read",
+						seenAt,
+					});
+				}
+			}
+		}
+	}
+}