diff --git a/README.md b/README.md
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+# @alkdev/operations
+
+Typed operations registry, call protocol, and adapters (MCP, OpenAPI).
+
+Every API endpoint, agent action, and tool is an **operation** with a TypeBox schema, access control metadata, and a handler. The registry stores specs and handlers independently. The call protocol provides unified event-based invocation — `call` and `subscribe` use the same events, same `PendingRequestMap`. Adapters generate operations from OpenAPI specs, MCP servers, and filesystem manifests.
+
+## Install
+
+```bash
+npm install @alkdev/operations
+```
+
+Optional peer dependencies (only if you need them):
+
+```bash
+npm install @alkdev/typemap       # for Zod/Valibot schema adapters
+npm install @modelcontextprotocol/sdk  # for MCP client integration
+```
+
+## Quick Start
+
+```ts
+import { Type } from "@alkdev/typebox";
+import { OperationRegistry, OperationType } from "@alkdev/operations";
+
+const registry = new OperationRegistry();
+
+registry.register({
+  name: "create",
+  namespace: "task",
+  version: "1.0.0",
+  type: OperationType.MUTATION,
+  description: "Create a new task",
+  inputSchema: Type.Object({
+    title: Type.String(),
+    priority: Type.Optional(Type.Union([Type.Literal("low"), Type.Literal("high")])),
+  }),
+  outputSchema: Type.Object({
+    id: Type.String(),
+    title: Type.String(),
+  }),
+  accessControl: { requiredScopes: ["task:write"] },
+  handler: async (input) => {
+    return { id: crypto.randomUUID(), title: input.title };
+  },
+});
+
+const result = await registry.execute(
+  "task.create",
+  { title: "Ship it", priority: "high" },
+  { identity: { id: "user-1", scopes: ["task:write"] } },
+);
+
+console.log(result.data);
+```
+
+## Core Concepts
+
+- **OperationSpec** — serializable descriptor: name, namespace, type, schemas, access control
+- **OperationHandler** — the function that runs when the operation is called
+- **OperationRegistry** — register specs and handlers, execute operations, validate I/O
+- **PendingRequestMap** — event-based call protocol: `call()`, `respond()`, `emitError()`, `abort()`
+- **ResponseEnvelope** — universal result wrapper with transport metadata (`local`, `http`, `mcp`)
+- **buildEnv()** — generate a nested call surface for inter-operation composition
+
+## Entry Points
+
+| Import | Purpose |
+|--------|---------|
+| `@alkdev/operations` | Core: registry, call protocol, envelopes, env, validation, errors, FromSchema |
+| `@alkdev/operations/from-mcp` | MCP client integration (requires `@modelcontextprotocol/sdk`) |
+| `@alkdev/operations/from-openapi` | OpenAPI integration |
+| `@alkdev/operations/from-typemap` | Zod/Valibot schema adapters (requires `@alkdev/typemap`) |
+
+## Guides
+
+| Guide | Topic |
+|-------|-------|
+| [Registry](docs/registry.md) | Defining, registering, and executing operations |
+| [Call Protocol](docs/call-protocol.md) | PendingRequestMap, CallHandler, call/subscribe events |
+| [Subscriptions](docs/subscriptions.md) | Real-time streaming with async generators |
+| [Response Envelopes](docs/response-envelopes.md) | Universal result wrapper and transport metadata |
+| [Access Control](docs/access-control.md) | Scope and resource-based authorization |
+| [Composition](docs/env-and-composition.md) | Inter-operation calls with buildEnv |
+| [Error Handling](docs/errors.md) | CallError, infrastructure codes, mapError |
+| [Adapters](docs/adapters.md) | MCP, OpenAPI, FromSchema, scanner, typemap |
+| [Validation](docs/validation.md) | Schema validation helpers |
+
+## API Reference
+
+For detailed type signatures, see [docs/architecture/api-surface.md](docs/architecture/api-surface.md).
+
+## License
+
+MIT OR Apache-2.0
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diff --git a/docs/access-control.md b/docs/access-control.md
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+# Access Control
+
+Operations declare their access requirements in `accessControl`. The registry and call handler enforce these before executing the handler.
+
+## AccessControl Fields
+
+```ts
+interface AccessControl {
+  requiredScopes: string[];       // ALL must be present (AND)
+  requiredScopesAny?: string[];   // At least ONE must match (OR)
+  resourceType?: string;          // e.g., "project", "tool"
+  resourceAction?: string;        // e.g., "read", "write", "execute"
+}
+```
+
+### requiredScopes (AND)
+
+Every scope in the array must be present in the caller's identity:
+
+```ts
+accessControl: {
+  requiredScopes: ["task:read", "task:write"],
+}
+```
+
+The caller must have **both** `task:read` and `task:write`.
+
+### requiredScopesAny (OR)
+
+At least one scope must match:
+
+```ts
+accessControl: {
+  requiredScopes: ["admin"],
+  requiredScopesAny: ["task:read", "task:write"],
+}
+```
+
+The caller needs `admin` AND either `task:read` or `task:write`.
+
+### Resource-based access
+
+When both `resourceType` and `resourceAction` are set, the caller's `resources` map is checked:
+
+```ts
+accessControl: {
+  requiredScopes: [],
+  resourceType: "project",
+  resourceAction: "read",
+}
+```
+
+The identity must have `resources` with a key matching `project:*` and `"read"` in the actions array:
+
+```ts
+identity: {
+  id: "user-1",
+  scopes: [],
+  resources: { "project:abc": ["read", "write"] },
+}
+```
+
+## Identity
+
+```ts
+interface Identity {
+  id: string;
+  scopes: string[];
+  resources?: Record<string, string[]>;
+}
+```
+
+## Enforcement
+
+### enforceAccess()
+
+Throws `CallError(ACCESS_DENIED)` if access is denied:
+
+```ts
+import { enforceAccess } from "@alkdev/operations";
+
+enforceAccess(spec.accessControl, context.identity, operationId, context.trusted);
+```
+
+Used internally by `registry.execute()` and `subscribe()`. Passes automatically if `context.trusted` is `true`.
+
+### checkAccess()
+
+Returns a boolean without throwing:
+
+```ts
+import { checkAccess } from "@alkdev/operations";
+
+if (!checkAccess(spec.accessControl, identity)) {
+  // deny access
+}
+```
+
+## Trusted Contexts
+
+When `buildEnv()` creates an `OperationEnv` for inter-operation calls, it sets `trusted: true` on the context. This bypasses all access control checks, allowing internal operations to call each other without needing every scope.
+
+Direct `registry.execute()` calls within a process can also pass `trusted: true`, but **untrusted callers should go through the call protocol** which always enforces access control.
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diff --git a/docs/adapters.md b/docs/adapters.md
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+# Adapters
+
+Adapters register operations from external sources. Each adapter converts external definitions (JSON Schema, OpenAPI, MCP tools) into `OperationSpec` + handler pairs that plug into the registry.
+
+## FromSchema
+
+`FromSchema` converts JSON Schema to TypeBox schemas. Used internally by OpenAPI and MCP adapters, but also useful standalone:
+
+```ts
+import { FromSchema } from "@alkdev/operations";
+
+const typeboxSchema = FromSchema({
+  type: "object",
+  properties: {
+    name: { type: "string" },
+    age: { type: "integer" },
+  },
+  required: ["name"],
+});
+```
+
+Supports: `object`, `array`, `string`, `number`, `integer`, `boolean`, `null`, `enum`, `allOf`, `anyOf`, `oneOf`, `$ref`, `const`, and tuples.
+
+## Schema Adapters (from-typemap)
+
+If you use Zod or Valibot schemas instead of TypeBox, the `SchemaAdapter` interface lets you register operations with your preferred schema library:
+
+```ts
+import { OperationRegistry } from "@alkdev/operations";
+import { zodAdapter } from "@alkdev/operations/from-typemap";
+import { z } from "zod";
+
+const adapter = zodAdapter();
+await adapter.init();
+
+const registry = new OperationRegistry({ schemaAdapter: adapter });
+
+registry.register({
+  name: "create",
+  namespace: "task",
+  version: "1.0.0",
+  type: OperationType.MUTATION,
+  description: "Create a task",
+  inputSchema: z.object({ title: z.string() }),   // Zod schema!
+  outputSchema: z.object({ id: z.string() }),
+  accessControl: { requiredScopes: [] },
+  handler: async (input) => ({ id: crypto.randomUUID(), ...input }),
+});
+```
+
+### Available adapters
+
+| Import | Adapter | Requires |
+|--------|---------|----------|
+| `defaultAdapter` | Pass-through TypeBox | Nothing |
+| `zodAdapter()` | Zod → TypeBox via `@alkdev/typemap` | `@alkdev/typemap` + `zod` |
+| `valibotAdapter()` | Valibot → TypeBox via `@alkdev/typemap` | `@alkdev/typemap` + `valibot` |
+
+Import from the `from-typemap` sub-path:
+
+```ts
+import { zodAdapter, valibotAdapter, defaultAdapter } from "@alkdev/operations/from-typemap";
+```
+
+> `defaultAdapter` is used by `OperationRegistry` when no adapter is specified. It passes TypeBox schemas through unchanged and throws for non-TypeBox schemas.
+
+## MCP Client (from-mcp)
+
+Connect to MCP servers and register their tools as operations.
+
+### createMCPClient
+
+Create a single MCP client connection:
+
+```ts
+import { createMCPClient, closeMCPClient } from "@alkdev/operations/from-mcp";
+
+const wrapper = await createMCPClient("my-server", {
+  command: "npx",
+  args: ["my-mcp-server"],
+  env: { API_KEY: "..." },
+});
+
+// wrapper.tools is an array of OperationSpec + handler
+registry.registerAll(wrapper.tools);
+
+// When done:
+await closeMCPClient(wrapper);
+```
+
+For HTTP-based servers:
+
+```ts
+const wrapper = await createMCPClient("remote-server", {
+  url: "https://example.com/mcp",
+  headers: { Authorization: "Bearer ..." },
+});
+```
+
+### MCPClientLoader
+
+Manages multiple MCP clients:
+
+```ts
+import { MCPClientLoader } from "@alkdev/operations/from-mcp";
+
+const loader = new MCPClientLoader();
+await loader.load({
+  "filesystem": { command: "npx", args: ["@modelcontextprotocol/server-filesystem", "/tmp"] },
+  "github": { command: "npx", args: ["@modelcontextprotocol/server-github"], env: { GITHUB_TOKEN: "..." } },
+});
+
+// Register all tools into a registry
+loader.registerAll(registry);
+
+// Access individual clients:
+const fsClient = loader.getClient("filesystem");
+
+// Cleanup
+await loader.closeAll();
+```
+
+### MCPClientConfig
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `command` | `string` | Stdio transport: command to run |
+| `args` | `string[]` | Arguments for the command |
+| `env` | `Record<string, string>` | Environment variables |
+| `cwd` | `string` | Working directory |
+| `url` | `string` | HTTP transport: server URL |
+| `headers` | `Record<string, string>` | HTTP headers (for `url` transport) |
+| `version` | `string` | Version string for the operation specs |
+
+MCP tool results are wrapped in `mcpEnvelope()` with structured content blocks. If `structuredContent` is present and the output schema is not `Unknown`, it's cast through the schema.
+
+## OpenAPI (from-openapi)
+
+Import REST API operations from OpenAPI specs.
+
+### FromOpenAPI
+
+```ts
+import { FromOpenAPI } from "@alkdev/operations/from-openapi";
+
+const operations = FromOpenAPI(spec, {
+  namespace: "petstore",
+  baseUrl: "https://petstore.example.com",
+  headers: { Authorization: "Bearer ..." },
+});
+
+registry.registerAll(operations);
+```
+
+### FromOpenAPIFile
+
+```ts
+import { FromOpenAPIFile } from "@alkdev/operations/from-openapi";
+
+const operations = await FromOpenAPIFile("./openapi.json", {
+  namespace: "petstore",
+  baseUrl: "https://petstore.example.com",
+});
+```
+
+For Deno or other non-Node runtimes, inject an `OpenAPIFS`:
+
+```ts
+const operations = await FromOpenAPIFile("./openapi.json", config, {
+  readFile: async (path) => Deno.readTextFile(path),
+});
+```
+
+### FromOpenAPIUrl
+
+```ts
+import { FromOpenAPIUrl } from "@alkdev/operations/from-openapi";
+
+const operations = await FromOpenAPIUrl("https://petstore.example.com/openapi.json", config);
+```
+
+### OpenAPIServiceRegistry
+
+Manages multiple OpenAPI services:
+
+```ts
+import { OpenAPIServiceRegistry } from "@alkdev/operations/from-openapi";
+
+const serviceRegistry = new OpenAPIServiceRegistry();
+serviceRegistry.add("petstore", spec, config);
+await serviceRegistry.addFromUrl("github", "https://api.github.com/openapi.json", config);
+serviceRegistry.registerAll(registry);
+```
+
+### HTTPServiceConfig
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `namespace` | `string` | Namespace for generated operations |
+| `baseUrl` | `string` | Base URL for HTTP requests |
+| `headers` | `Record<string, string>` | Default headers |
+| `auth` | `object` | Auth config: `bearer`, `apiKey`, or `basic` |
+| `timeout` | `number` | Request timeout in ms |
+| `fetch` | `typeof fetch` | Custom fetch implementation |
+
+### SSE Support
+
+Operations with `text/event-stream` response content type are automatically typed as `SUBSCRIPTION`. The handler returns an async generator that parses SSE frames and yields `httpEnvelope` events.
+
+### Operation Type Detection
+
+- `GET` → `QUERY`
+- `POST`/`PUT`/`PATCH`/`DELETE` → `MUTATION`
+- Any method with `text/event-stream` response → `SUBSCRIPTION`
+
+## Scanner
+
+`scanOperations` auto-discovers operations from the filesystem by importing `.ts` files that export a default `OperationSpec`:
+
+```ts
+import { scanOperations } from "@alkdev/operations";
+
+const specs = await scanOperations("./operations", {
+  readdir: async function* (path) { /* ... */ },
+  cwd: () => process.cwd(),
+});
+```
+
+The `ScannerFS` interface makes it runtime-agnostic:
+
+```ts
+interface ScannerFS {
+  readdir(path: string): AsyncIterable<{ name: string; isFile: boolean; isDirectory: boolean }>;
+  cwd(): string;
+}
+```
+
+Each `.ts` file must export a default that validates against `OperationSpecSchema`. Files that don't pass validation are skipped with a warning.
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diff --git a/docs/call-protocol.md b/docs/call-protocol.md
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+# Call Protocol
+
+The call protocol provides event-based operation invocation via `@alkdev/pubsub`. It uses the same events and `PendingRequestMap` for both one-shot calls and streaming subscriptions. The key insight: **call ≡ subscribe** — a call resolves after one response event; a subscription yields events until completed or aborted.
+
+## PendingRequestMap
+
+`PendingRequestMap` is the core of the call protocol. It manages pending calls and subscriptions through a pubsub layer.
+
+### Creating a CallMap
+
+```ts
+import { PendingRequestMap } from "@alkdev/operations";
+
+const callMap = new PendingRequestMap();
+```
+
+Optionally pass an `EventTarget` for cross-window/cross-worker communication:
+
+```ts
+const callMap = new PendingRequestMap(myEventTarget);
+```
+
+### Making a Call
+
+```ts
+const envelope = await callMap.call("task.create", { title: "Ship it" }, {
+  deadline: Date.now() + 5000,
+  identity: { id: "user-1", scopes: ["task:write"] },
+});
+```
+
+This:
+1. Creates a unique `requestId`
+2. Publishes a `call.requested` event
+3. Returns a `Promise<ResponseEnvelope>` that resolves when `respond()` is called with that `requestId`
+
+### Subscribing
+
+```ts
+const stream = callMap.subscribe("events.watch", { filter: "important" }, {
+  idleTimeout: 30000,
+  identity: { id: "user-1", scopes: ["events:read"] },
+});
+
+for await (const envelope of stream) {
+  console.log(envelope.data);
+}
+```
+
+This:
+1. Creates a unique `requestId`
+2. Publishes a `call.requested` event (same as a call)
+3. Returns an `AsyncIterable<ResponseEnvelope>` that yields events until `completed`, `aborted`, or idle timeout
+
+### Responding
+
+```ts
+callMap.respond(requestId, envelope);
+```
+
+Sends a `call.responded` event. For calls, this resolves the promise. For subscriptions, this yields the next event.
+
+### Error Handling
+
+```ts
+callMap.emitError(requestId, "VALIDATION_ERROR", "Input was invalid", { field: "title" });
+```
+
+Sends a `call.error` event. For calls, this rejects the promise with a `CallError`. For subscriptions, this stops the stream with an error.
+
+### Completing a Subscription
+
+```ts
+callMap.complete(requestId);
+```
+
+Signals that no more events will be sent. Ends the subscription stream.
+
+### Aborting
+
+```ts
+callMap.abort(requestId);
+```
+
+Aborts a pending call or subscription. Rejects the call promise or stops the subscription stream with an `ABORTED` error code.
+
+## CallHandler
+
+`buildCallHandler()` wires a `PendingRequestMap` to an `OperationRegistry`. It listens for `call.requested` events and routes them through the registry.
+
+```ts
+import { PendingRequestMap, buildCallHandler } from "@alkdev/operations";
+
+const callMap = new PendingRequestMap();
+const handler = buildCallHandler({ registry, callMap });
+
+callMap["call.requested"].subscribe(handler);
+```
+
+The handler:
+1. Extracts `operationId`, `input`, and `identity` from the event
+2. For queries/mutations: calls `registry.execute()` and responds with the result
+3. For subscriptions: delegates to `subscribe()` and streams results back
+4. On error: calls `callMap.emitError()` with a mapped `CallError`
+
+## Event Types
+
+| Event | Purpose | Producer | Consumer |
+|-------|---------|----------|----------|
+| `call.requested` | Initiate a call or subscription | Caller | Handler |
+| `call.responded` | Deliver a result | Handler | Caller |
+| `call.completed` | Signal end of subscription | Handler | Caller |
+| `call.aborted` | Cancel request | Caller or Handler | Opposite side |
+| `call.error` | Signal an error | Handler | Caller |
+
+Each event carries a `requestId` for correlation.
+
+## Event Schemas
+
+All events are typed TypeBox schemas available as `CallEventMap`:
+
+```ts
+import { CallEventMap } from "@alkdev/operations";
+
+// Access type schemas:
+CallEventMap["call.requested"]  // TypeBox schema
+CallEventMap["call.responded"]   // TypeBox schema
+```
+
+## Timeout Behavior
+
+**Calls** use `deadline` — an absolute timestamp (ms since epoch). If the deadline passes without a response, the promise rejects with a `TIMEOUT` error.
+
+**Subscriptions** use `idleTimeout` — a relative duration (ms). If no event is received within this window, the subscription is aborted with a `TIMEOUT` error.
+
+## Usage Pattern
+
+A typical server setup:
+
+```ts
+const registry = new OperationRegistry();
+const callMap = new PendingRequestMap();
+const handler = buildCallHandler({ registry, callMap });
+
+// Wire to your transport (WebSocket, HTTP, etc.)
+transport.on("call.requested", handler);
+
+// Or directly use the registry for in-process calls:
+const result = await registry.execute("task.create", input, ctx);
+```
+
+See [Subscriptions](subscriptions.md) for the direct async generator approach (no pubsub needed).
\ No newline at end of file
diff --git a/docs/env-and-composition.md b/docs/env-and-composition.md
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+# Composition (buildEnv)
+
+Operations often need to call other operations. `buildEnv()` generates an `OperationEnv` — a nested record of namespace → operation name → caller — that lets handlers invoke other operations without knowing the registry.
+
+## Creating an Environment
+
+```ts
+import { buildEnv } from "@alkdev/operations";
+
+const env = buildEnv({
+  registry,
+  context: { identity: { id: "user-1", scopes: ["task:read"] } },
+  allowedNamespaces: ["task", "user"],
+});
+```
+
+This walks all non-subscription specs in the registry and creates a callable function for each one.
+
+### Result Shape
+
+```ts
+// env mirrors the registry's namespace.name structure:
+env.task.create({ title: "New task" });    // Promise<ResponseEnvelope>
+env.task.list({ filter: "active" });        // Promise<ResponseEnvelope>
+env.user.get({ id: "user-1" });            // Promise<ResponseEnvelope>
+```
+
+Each function calls `registry.execute()` under the hood.
+
+## Trusted Calls
+
+All calls made through `buildEnv()` set `trusted: true` on the context. This means:
+
+- Access control checks are **skipped**
+- The caller's identity propagates, but scopes are not enforced
+- Input/output validation still runs
+
+This is intentional — internal composition shouldn't require every internal operation to have every scope. Access control is enforced at the boundary (the call protocol), not between internal operations.
+
+## Usage in Handlers
+
+```ts
+const createAndNotify = {
+  name: "createAndNotify",
+  namespace: "task",
+  version: "1.0.0",
+  type: OperationType.MUTATION,
+  description: "Create a task and send a notification",
+  inputSchema: Type.Object({ title: Type.String(), assignee: Type.String() }),
+  outputSchema: Type.Object({ taskId: Type.String(), notified: Type.Boolean() }),
+  accessControl: { requiredScopes: ["task:write"] },
+  handler: async (input, context) => {
+    const task = await context.env!.task.create(input);
+    await context.env!.notification.send({ userId: input.assignee, message: "New task" });
+    return { taskId: task.data.id, notified: true };
+  },
+};
+```
+
+## Options
+
+| Option | Type | Description |
+|--------|------|-------------|
+| `registry` | `OperationRegistry` | Required. The registry to build from. |
+| `context` | `OperationContext` | Required. Base context (identity, metadata, etc.) |
+| `allowedNamespaces` | `string[]` | Optional. Only include operations from these namespaces. |
+
+Subscriptions are excluded from the env (they can't be awaited). Use `subscribe()` directly for subscription composition.
\ No newline at end of file
diff --git a/docs/errors.md b/docs/errors.md
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+++ b/docs/errors.md
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+# Error Handling
+
+## CallError
+
+All operational errors are represented as `CallError`, which extends `Error` with a structured `code` and optional `details`:
+
+```ts
+class CallError extends Error {
+  readonly code: CallErrorCode;
+  readonly details?: unknown;
+}
+```
+
+```ts
+import { CallError, InfrastructureErrorCode } from "@alkdev/operations";
+
+throw new CallError(InfrastructureErrorCode.OPERATION_NOT_FOUND, "Operation not found: foo.bar", { operationId: "foo.bar" });
+```
+
+## Infrastructure Error Codes
+
+Built-in codes for framework-level errors:
+
+| Code | When |
+|------|------|
+| `OPERATION_NOT_FOUND` | No spec or handler registered for the operation ID |
+| `ACCESS_DENIED` | Caller lacks required scopes or resource access |
+| `VALIDATION_ERROR` | Input fails schema validation |
+| `TIMEOUT` | Call or subscription timed out (deadline or idle) |
+| `ABORTED` | Request was explicitly aborted |
+| `EXECUTION_ERROR` | Handler threw an Error that didn't match any declared error code |
+| `UNKNOWN_ERROR` | Non-Error value thrown from handler |
+
+You can also use custom error codes as strings:
+
+```ts
+throw new CallError("INVALID_INPUT", "Title is required", { field: "title" });
+```
+
+## Declared Errors
+
+Operations can declare expected error codes in their spec:
+
+```ts
+{
+  errorSchemas: [
+    { code: "INVALID_INPUT", description: "Input validation failed", schema: Type.Object({ field: Type.String() }) },
+    { code: "NOT_FOUND", description: "Task not found", schema: Type.Object({ id: Type.String() }) },
+  ],
+}
+```
+
+## mapError
+
+`mapError()` normalizes thrown values into `CallError`:
+
+```ts
+import { mapError } from "@alkdev/operations";
+
+const callError = mapError(thrownValue, spec.errorSchemas);
+```
+
+Logic:
+1. If already a `CallError`, returns it as-is
+2. If an `Error`, checks if its message matches any declared error code prefix (`CODE:` or exact `CODE`) — returns a `CallError` with that code
+3. Otherwise, returns `CallError(EXECUTION_ERROR, error.message, error)`
+
+This is used internally by `buildCallHandler()` to map handler errors into the call protocol error format.
+
+## Error Propagation
+
+| Context | Behavior |
+|---------|----------|
+| `registry.execute()` | Throws `CallError` directly |
+| `subscribe()` | Throws `CallError` into the async generator |
+| `PendingRequestMap` | Emits `call.error` event, rejected promise or stopped stream |
+| `buildEnv()` calls | Propagates `CallError` from the nested `execute()` |
\ No newline at end of file
diff --git a/docs/registry.md b/docs/registry.md
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index 0000000..e366f61
--- /dev/null
+++ b/docs/registry.md
@@ -0,0 +1,174 @@
+# Registry
+
+The `OperationRegistry` is the central store for operation specs and handlers. It handles registration, validation, access control enforcement, and execution.
+
+## Operation Types
+
+```ts
+enum OperationType {
+  QUERY = "query",
+  MUTATION = "mutation",
+  SUBSCRIPTION = "subscription",
+}
+```
+
+- **Query** — read-only, no side effects
+- **Mutation** — writes state, side effects
+- **Subscription** — streams results over time (async generator handler)
+
+## Defining an Operation
+
+Every operation has a **spec** (serializable metadata) and optionally a **handler** (the function that runs).
+
+```ts
+import { Type } from "@alkdev/typebox";
+import { OperationType } from "@alkdev/operations";
+
+const createTask = {
+  name: "create",
+  namespace: "task",
+  version: "1.0.0",
+  type: OperationType.MUTATION,
+  description: "Create a new task",
+  inputSchema: Type.Object({
+    title: Type.String(),
+    priority: Type.Optional(Type.Union([Type.Literal("low"), Type.Literal("high")])),
+  }),
+  outputSchema: Type.Object({
+    id: Type.String(),
+    title: Type.String(),
+  }),
+  accessControl: {
+    requiredScopes: ["task:write"],
+  },
+  handler: async (input: { title: string; priority?: string }) => {
+    return { id: crypto.randomUUID(), title: input.title };
+  },
+};
+```
+
+### Spec Fields
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `name` | `string` | yes | Operation name within its namespace |
+| `namespace` | `string` | yes | Grouping (e.g. `"task"`, `"user"`) |
+| `version` | `string` | yes | Semantic version |
+| `type` | `OperationType` | yes | `query`, `mutation`, or `subscription` |
+| `description` | `string` | yes | Human-readable description |
+| `inputSchema` | `TSchema` | yes | TypeBox schema for input validation |
+| `outputSchema` | `TSchema` | yes | TypeBox schema for output; use `Type.Unknown()` if untyped |
+| `accessControl` | `AccessControl` | yes | Scopes and resource requirements (see [Access Control](access-control.md)) |
+| `title` | `string` | no | Human-readable title |
+| `tags` | `string[]` | no | Tags for filtering/grouping |
+| `errorSchemas` | `ErrorDefinition[]` | no | Declared error codes and their schemas |
+| `_meta` | `Record<string, unknown>` | no | Arbitrary metadata |
+
+### Handler Signature
+
+**Query/Mutation** handlers return a value (or `ResponseEnvelope`):
+
+```ts
+type OperationHandler<TInput, TOutput> = (
+  input: TInput,
+  context: OperationContext,
+) => Promise<TOutput> | TOutput;
+```
+
+**Subscription** handlers must be async generators:
+
+```ts
+type SubscriptionHandler<TInput, TOutput> = (
+  input: TInput,
+  context: OperationContext,
+) => AsyncGenerator<TOutput, void, unknown>;
+```
+
+## Registering Operations
+
+### Combined registration
+
+```ts
+const registry = new OperationRegistry();
+registry.register(createTask);
+```
+
+`register()` stores both the spec and the handler. The `handler` field is optional — you can register the spec first and add the handler later.
+
+### Batch registration
+
+```ts
+registry.registerAll([createTask, listTasks, deleteTask]);
+```
+
+### Separate spec and handler
+
+```ts
+registry.registerSpec(mySpec);
+registry.registerHandler("task.create", myHandler);
+```
+
+This is useful when specs come from one source (e.g., OpenAPI import) and handlers from another.
+
+> `registerHandler` throws if no spec exists for the operation ID.
+
+## Executing Operations
+
+```ts
+const envelope = await registry.execute(
+  "task.create",
+  { title: "Ship it" },
+  { identity: { id: "user-1", scopes: ["task:write"] } },
+);
+```
+
+What `execute()` does:
+
+1. Looks up the spec by `namespace.name`
+2. Looks up the handler
+3. **Enforces access control** (unless `context.trusted` is `true`)
+4. **Validates input** against the spec's `inputSchema`
+5. Runs the handler
+6. **Wraps the result** in a `ResponseEnvelope` if not already one
+7. **Casts the output** through `outputSchema` and warns on validation errors
+
+Returns `ResponseEnvelope<TOutput>`. See [Response Envelopes](response-envelopes.md).
+
+### Execution context
+
+```ts
+interface OperationContext {
+  requestId?: string;
+  parentRequestId?: string;
+  identity?: Identity;
+  trusted?: boolean;       // set by buildEnv, not by callers
+  metadata?: Record<string, unknown>;
+  env?: OperationEnv;       // injected by buildEnv for inter-op calls
+}
+```
+
+## Querying the Registry
+
+```ts
+registry.get("task.create");        // spec + handler, or undefined
+registry.getSpec("task.create");    // spec only
+registry.getHandler("task.create"); // handler only
+registry.getByName("task", "create"); // same as get("task.create")
+registry.list();                    // all specs + handlers
+registry.getAllSpecs();              // all specs only
+```
+
+## Schema Adapters
+
+By default, the registry expects TypeBox schemas. If you use Zod or Valibot, pass a schema adapter:
+
+```ts
+import { zodAdapter } from "@alkdev/operations/from-typemap";
+
+const adapter = zodAdapter();
+await adapter.init();
+
+const registry = new OperationRegistry({ schemaAdapter: adapter });
+```
+
+See [Adapters](adapters.md) for details.
\ No newline at end of file
diff --git a/docs/response-envelopes.md b/docs/response-envelopes.md
new file mode 100644
index 0000000..d8297f9
--- /dev/null
+++ b/docs/response-envelopes.md
@@ -0,0 +1,111 @@
+# Response Envelopes
+
+All operation results are wrapped in a `ResponseEnvelope<T>` that carries transport metadata alongside the data. This provides a uniform result type regardless of whether the operation ran locally, over HTTP, or via MCP.
+
+## Structure
+
+```ts
+interface ResponseEnvelope<T = unknown> {
+  data: T;
+  meta: ResponseMeta;
+}
+```
+
+`meta.source` is the discriminant:
+
+| Source | Type | Carries |
+|--------|------|---------|
+| `"local"` | `LocalResponseMeta` | `operationId`, `timestamp` |
+| `"http"` | `HTTPResponseMeta` | `statusCode`, `headers`, `contentType` |
+| `"mcp"` | `MCPResponseMeta` | `isError`, `content[]`, `structuredContent?`, `_meta?` |
+
+## Creating Envelopes
+
+### localEnvelope
+
+For in-process results:
+
+```ts
+import { localEnvelope } from "@alkdev/operations";
+
+const env = localEnvelope({ id: "123", title: "My task" }, "task.create");
+```
+
+### httpEnvelope
+
+For HTTP-sourced results (e.g., OpenAPI adapter):
+
+```ts
+import { httpEnvelope } from "@alkdev/operations";
+
+const env = httpEnvelope(data, {
+  statusCode: 200,
+  headers: { "content-type": "application/json" },
+  contentType: "application/json",
+});
+```
+
+### mcpEnvelope
+
+For MCP-sourced results:
+
+```ts
+import { mcpEnvelope } from "@alkdev/operations";
+
+const env = mcpEnvelope(data, {
+  isError: false,
+  content: [{ type: "text", text: "Done" }],
+});
+```
+
+## Unwrapping
+
+```ts
+import { unwrap } from "@alkdev/operations";
+
+const result = unwrap(envelope);
+```
+
+Returns `envelope.data`, discarding transport metadata.
+
+## Detecting Envelopes
+
+```ts
+import { isResponseEnvelope } from "@alkdev/operations";
+
+if (isResponseEnvelope(maybeEnvelope)) {
+  // TypeScript narrows to ResponseEnvelope
+}
+```
+
+Checks that the value has `data` and `meta` with a recognized `source` ("local" | "http" | "mcp") and the appropriate source-specific fields.
+
+## Automatic Wrapping
+
+When an operation handler returns a plain value (not a `ResponseEnvelope`), `registry.execute()` and `subscribe()` wrap it in a `localEnvelope()` automatically. If the handler already returns a `ResponseEnvelope`, it passes through unchanged.
+
+## MCP Content Blocks
+
+MCP responses include structured content blocks:
+
+```ts
+type MCPContentBlock =
+  | { type: "text"; text: string; annotations?: MCPAnnotations }
+  | { type: "image"; data: string; mimeType: string; annotations?: MCPAnnotations }
+  | { type: "audio"; data: string; mimeType: string; annotations?: MCPAnnotations }
+  | { type: "resource"; resource: MCPResourceContent; annotations?: MCPAnnotations }
+  | { type: "resource_link"; uri: string; name: string; description?: string; mimeType?: string }
+```
+
+## TypeBox Schemas
+
+Both `ResponseEnvelopeSchema` and `ResponseMetaSchema` are available for runtime validation:
+
+```ts
+import { ResponseEnvelopeSchema, ResponseMetaSchema } from "@alkdev/operations";
+import { Value } from "@alkdev/typebox/value";
+
+if (Value.Check(ResponseEnvelopeSchema, value)) {
+  // valid envelope
+}
+```
\ No newline at end of file
diff --git a/docs/subscriptions.md b/docs/subscriptions.md
new file mode 100644
index 0000000..45cae75
--- /dev/null
+++ b/docs/subscriptions.md
@@ -0,0 +1,92 @@
+# Subscriptions
+
+Subscription operations stream results over time using async generators. There are two ways to use them:
+
+1. **Direct** — `subscribe()` calls the handler in-process, no pubsub needed
+2. **Via call protocol** — `PendingRequestMap.subscribe()` routes through the pubsub layer
+
+## Defining a Subscription Operation
+
+Subscription handlers must be **async generator functions** (`async function*`):
+
+```ts
+import { Type } from "@alkdev/typebox";
+import { OperationType } from "@alkdev/operations";
+
+const watchTasks = {
+  name: "watch",
+  namespace: "task",
+  version: "1.0.0",
+  type: OperationType.SUBSCRIPTION,
+  description: "Watch for task changes",
+  inputSchema: Type.Object({ filter: Type.Optional(Type.String()) }),
+  outputSchema: Type.Object({ id: Type.String(), title: Type.String(), status: Type.String() }),
+  accessControl: { requiredScopes: ["task:read"] },
+  handler: async function* (input, context) {
+    for (const event of someEventSource(input.filter)) {
+      yield event;
+    }
+  },
+};
+```
+
+> The registry validates at registration time that subscription handlers are async generators. A regular async function will throw.
+
+## Direct Subscription: `subscribe()`
+
+The `subscribe()` function executes a subscription handler and returns an async generator. No pubsub or call protocol needed.
+
+```ts
+import { subscribe } from "@alkdev/operations";
+
+const stream = subscribe(registry, "task.watch", { filter: "important" }, context);
+
+for await (const envelope of stream) {
+  console.log(envelope.data);
+}
+```
+
+`subscribe()`:
+1. Looks up the spec and handler
+2. Enforces access control
+3. Validates input
+4. Verifies the handler returns an async iterable
+5. Yields each value, wrapping non-envelope values in `localEnvelope()`
+
+### Error handling
+
+If the handler throws, the error propagates as a `CallError`. If the handler yields a non-iterable, `subscribe()` throws `EXECUTION_ERROR`.
+
+### Cleanup
+
+When the consumer breaks out of the `for await` loop, `subscribe()` calls `generator.return()` to clean up the handler.
+
+## Call Protocol Subscription
+
+When routing through `PendingRequestMap`:
+
+```ts
+const stream = callMap.subscribe("task.watch", { filter: "important" }, {
+  idleTimeout: 30000,
+  identity: { id: "user-1", scopes: ["task:read"] },
+});
+
+for await (const envelope of stream) {
+  console.log(envelope.data);
+}
+```
+
+The `CallHandler` will:
+1. Call `subscribe()` on the registry
+2. Stream each yielded envelope via `callMap.respond()`
+3. Call `callMap.complete()` when the generator finishes
+4. Call `callMap.emitError()` if an error occurs
+
+## Choosing Between Direct and Call Protocol
+
+| | Direct (`subscribe()`) | Call Protocol (`callMap.subscribe()`) |
+|---|---|---|
+| **Use when** | In-process, same runtime | Cross-process, remote callers |
+| **Transport** | Direct function call | PubSub events |
+| **Timeout** | Managed by consumer | `idleTimeout` parameter |
+| **Abort** | Consumer breaks loop | `callMap.abort(requestId)` |
\ No newline at end of file
diff --git a/docs/validation.md b/docs/validation.md
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--- /dev/null
+++ b/docs/validation.md
@@ -0,0 +1,53 @@
+# Validation
+
+TypeBox-based schema validation helpers for operation inputs and outputs.
+
+## validateOrThrow
+
+Validates a value against a TypeBox schema. Throws on failure with formatted error messages:
+
+```ts
+import { validateOrThrow } from "@alkdev/operations";
+
+validateOrThrow(schema, input, "Input validation failed for task.create");
+```
+
+Used internally by `registry.execute()` to validate inputs before running handlers.
+
+## collectErrors
+
+Returns an array of errors without throwing:
+
+```ts
+import { collectErrors } from "@alkdev/operations";
+
+const errors = collectErrors(schema, value);
+// [{ path: "/title", message: "Expected string" }, ...]
+```
+
+Used internally by `registry.execute()` to warn on output validation failures.
+
+## assertIsSchema
+
+Validates that a value is a TypeBox schema. Throws if not:
+
+```ts
+import { assertIsSchema } from "@alkdev/operations";
+
+assertIsSchema(maybeSchema, "task.create input");
+```
+
+Useful when receiving schemas from external sources (JSON, OpenAPI) before passing them to the registry.
+
+## formatValueErrors
+
+Formats an iterable of `{ path, message }` errors into a human-readable string:
+
+```ts
+import { formatValueErrors } from "@alkdev/operations";
+
+const formatted = formatValueErrors(errors);
+// "  - /title: Expected string\n  - /priority: Expected union member"
+```
+
+Accepts an optional indent prefix (default `"  - "`).
\ No newline at end of file