diff --git a/shared/.gitkeep b/shared/.gitkeep
deleted file mode 100644
index e69de29..0000000
diff --git a/shared/package.json b/shared/package.json
new file mode 100644
index 0000000..d46d3f5
--- /dev/null
+++ b/shared/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "@podman/shared",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "dev": "tsc -p tsconfig.json --watch",
+    "typecheck": "tsc -p tsconfig.json --noEmit"
+  }
+}
diff --git a/shared/src/collision.ts b/shared/src/collision.ts
new file mode 100644
index 0000000..84ecbaf
--- /dev/null
+++ b/shared/src/collision.ts
@@ -0,0 +1,29 @@
+export type CollisionSeverity = 'info' | 'warn' | 'critical';
+
+/**
+ * A detected overlap between two or more engineers' live work, fused from
+ * vision-derived contexts and GitHub state.
+ */
+export interface Collision {
+  id: string;
+  podId: string;
+  /** File both engineers are touching. */
+  file: string;
+  /** Symbol-level overlap, if known. */
+  symbol?: string;
+  /** Engineer ids involved in the overlap. */
+  engineers: string[];
+  severity: CollisionSeverity;
+  /** Snapshot of relevant GitHub state at detection time. */
+  githubState?: GithubStateSnapshot;
+  detectedAt: string;
+}
+
+export interface GithubStateSnapshot {
+  /** Open branches touching the file, keyed by engineer/login. */
+  branches?: Record<string, string>;
+  /** Open PR numbers touching the file. */
+  openPrs?: number[];
+  /** Whether any involved engineer has unpushed local changes. */
+  unpushed?: boolean;
+}
diff --git a/shared/src/engineer.ts b/shared/src/engineer.ts
new file mode 100644
index 0000000..53d94ab
--- /dev/null
+++ b/shared/src/engineer.ts
@@ -0,0 +1,21 @@
+/**
+ * What PodMan currently believes an engineer is doing, derived from vision on
+ * their shared screen and refreshed every few seconds. This is the live,
+ * pre-push signal that the GitHub API cannot see.
+ */
+export interface EngineerContext {
+  engineerId: string;
+  podId: string;
+  /** File path PodMan sees open/active in the editor, e.g. "src/auth.ts". */
+  currentFile?: string;
+  /** Function/class/symbol being edited, if vision can resolve it. */
+  currentSymbol?: string;
+  /** Higher-level feature/action inferred from the screen. */
+  activity?: string;
+  /** Whether the screen shows uncommitted/unpushed changes (gutter/diff). */
+  hasUnpushedChanges?: boolean;
+  /** 0–1 confidence in this read of the screen. */
+  confidence: number;
+  /** ISO timestamp of the observation this context came from. */
+  observedAt: string;
+}
diff --git a/shared/src/index.ts b/shared/src/index.ts
new file mode 100644
index 0000000..76de9c3
--- /dev/null
+++ b/shared/src/index.ts
@@ -0,0 +1,14 @@
+export type { Pod, Engineer } from './pod.js';
+export type { EngineerContext } from './engineer.js';
+export type {
+  Collision,
+  CollisionSeverity,
+  GithubStateSnapshot,
+} from './collision.js';
+export type {
+  Intervention,
+  InterventionKind,
+  InterventionStatus,
+  SuggestedAction,
+  SuggestedActionKind,
+} from './intervention.js';
diff --git a/shared/src/intervention.ts b/shared/src/intervention.ts
new file mode 100644
index 0000000..0d4d606
--- /dev/null
+++ b/shared/src/intervention.ts
@@ -0,0 +1,24 @@
+export type InterventionKind = 'voice' | 'card';
+
+export type InterventionStatus = 'pending' | 'delivered' | 'accepted' | 'dismissed';
+
+export type SuggestedActionKind = 'open_sync_pr' | 'ping_teammate' | 'none';
+
+/** What PodMan says/does about a collision — the product's hero output. */
+export interface Intervention {
+  id: string;
+  collisionId: string;
+  podId: string;
+  kind: InterventionKind;
+  /** Spoken/displayed message, e.g. "Karti and Yahya are both in auth.ts...". */
+  message: string;
+  suggestedAction: SuggestedAction;
+  status: InterventionStatus;
+  createdAt: string;
+}
+
+export interface SuggestedAction {
+  kind: SuggestedActionKind;
+  /** Free-form payload for the action (e.g. branch names for a sync PR). */
+  params?: Record<string, unknown>;
+}
diff --git a/shared/src/pod.ts b/shared/src/pod.ts
new file mode 100644
index 0000000..6b25b2b
--- /dev/null
+++ b/shared/src/pod.ts
@@ -0,0 +1,19 @@
+/** A pod is one room of engineers working together (one LiveKit room per pod). */
+export interface Pod {
+  id: string;
+  name: string;
+  /** GitHub repo the pod is working in, as "owner/name". */
+  repo: string;
+  members: Engineer[];
+  createdAt: string;
+}
+
+export interface Engineer {
+  id: string;
+  /** Display name PodMan uses when it speaks ("Karti and Yahya are both..."). */
+  name: string;
+  /** GitHub login, used to map vision context to GitHub state. */
+  githubLogin?: string;
+  /** LiveKit participant identity for this engineer in the pod room. */
+  participantId?: string;
+}
diff --git a/shared/tsconfig.json b/shared/tsconfig.json
new file mode 100644
index 0000000..03ce790
--- /dev/null
+++ b/shared/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "extends": "../tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "./dist",
+    "rootDir": "./src"
+  },
+  "include": ["src/**/*"]
+}