diff --git a/package.json b/package.json
index b48cbdedbc..7c1a7756d9 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,7 @@
     "lint": "oxlint --quiet src modules",
     "lint-native": "swiftlint ./modules && ktlint ./modules",
     "lint-native:fix": "swiftlint --fix ./modules && ktlint --format ./modules",
-    "lexicons:generate": "lex build --clear --index-file",
+    "lexicons:generate": "lex build --clear --index-file --import-ext ''",
     "lexicons:update": "lex install --update",
     "typecheck": "pnpm run typecheck:ios && pnpm run typecheck:android && pnpm run typecheck:web",
     "typecheck:ios": "tsc --project ./tsconfig.check.ios.json",
diff --git a/src/state/queries/trending/useGetTrendsQuery.ts b/src/state/queries/trending/useGetTrendsQuery.ts
index 757e868d1f..e7d6806b3e 100644
--- a/src/state/queries/trending/useGetTrendsQuery.ts
+++ b/src/state/queries/trending/useGetTrendsQuery.ts
@@ -1,5 +1,5 @@
 import {useCallback, useMemo} from 'react'
-import {type AppBskyUnspeccedGetTrends, hasMutedWord} from '@atproto/api'
+import {hasMutedWord} from '@atproto/api'
 import {useQuery} from '@tanstack/react-query'
 
 import {
@@ -10,7 +10,8 @@ import {logger} from '#/logger'
 import {getContentLanguages} from '#/state/preferences/languages'
 import {STALE} from '#/state/queries'
 import {usePreferencesQuery} from '#/state/queries/preferences'
-import {useAgent} from '#/state/session'
+import {useLexClient} from '#/state/session'
+import {app} from '#/lexicons'
 
 export const DEFAULT_LIMIT = 5
 
@@ -32,7 +33,7 @@ export const createGetTrendsQueryKey = (limit?: number) =>
   limit === undefined ? ['trends'] : ['trends', {limit}]
 
 export function useGetTrendsQuery(props: QueryProps = {}) {
-  const agent = useAgent()
+  const client = useLexClient()
   const {data: preferences} = usePreferencesQuery()
   const limit = props.limit ?? DEFAULT_LIMIT
   const mutedWords = useMemo(() => {
@@ -46,7 +47,8 @@ export function useGetTrendsQuery(props: QueryProps = {}) {
     queryKey: createGetTrendsQueryKey(limit),
     queryFn: async () => {
       const contentLangs = getContentLanguages().join(',')
-      const {data} = await agent.app.bsky.unspecced.getTrends(
+      const data = await client.call(
+        app.bsky.unspecced.getTrends,
         {
           limit,
         },
@@ -63,7 +65,7 @@ export function useGetTrendsQuery(props: QueryProps = {}) {
       return data
     },
     select: useCallback(
-      (data: AppBskyUnspeccedGetTrends.OutputSchema) => {
+      (data: app.bsky.unspecced.getTrends.$OutputBody) => {
         return {
           recId: data.recIdStr,
           trends: dedupe(
diff --git a/src/state/session/__tests__/clients-test.ts b/src/state/session/__tests__/clients-test.ts
new file mode 100644
index 0000000000..c04e2d9ea7
--- /dev/null
+++ b/src/state/session/__tests__/clients-test.ts
@@ -0,0 +1,70 @@
+import {type AtpAgent} from '@atproto/api'
+import {Client} from '@atproto/lex-client'
+import {describe, expect, it, jest} from '@jest/globals'
+
+import {app} from '#/lexicons'
+import {agentToLexClient} from '../clients'
+
+/**
+ * Minimal stand-in for the parts of AtpAgent that `agentToLexClient` reads: a
+ * `did` and a `fetchHandler`. Returned as `AtpAgent` via a cast since we only
+ * exercise those two members.
+ */
+function makeFakeAgent(did: string | undefined) {
+  const fetchHandler = jest.fn(
+    (_path: string, _init: RequestInit): Promise<Response> =>
+      Promise.resolve(
+        new Response(
+          JSON.stringify({
+            did: 'did:plc:fake',
+            handle: 'fake.bsky.social',
+          }),
+          {status: 200, headers: {'content-type': 'application/json'}},
+        ),
+      ),
+  )
+  const agent = {did, fetchHandler}
+  return {agent: agent as unknown as AtpAgent, fetchHandler}
+}
+
+describe('agentToLexClient', () => {
+  it('routes client.call through the agent fetchHandler', async () => {
+    const {agent, fetchHandler} = makeFakeAgent('did:plc:fake')
+    const client = agentToLexClient(agent)
+
+    const result = await client.call(app.bsky.actor.getProfile.main, {
+      actor: 'fake.bsky.social',
+    })
+
+    expect(fetchHandler).toHaveBeenCalledTimes(1)
+    const [path] = fetchHandler.mock.calls[0]
+    expect(path).toContain('/xrpc/app.bsky.actor.getProfile')
+    expect(path).toContain('actor=fake.bsky.social')
+    expect(result.handle).toBe('fake.bsky.social')
+  })
+
+  it('passes through the agent did', () => {
+    const {agent} = makeFakeAgent('did:plc:fake')
+    const client = agentToLexClient(agent)
+    expect(client.did).toBe('did:plc:fake')
+  })
+
+  it('reflects an undefined did (unauthenticated agent)', () => {
+    const {agent} = makeFakeAgent(undefined)
+    const client = agentToLexClient(agent)
+    expect(client.did).toBeUndefined()
+  })
+
+  it('memoizes one client per agent', () => {
+    const {agent: agentA} = makeFakeAgent('did:plc:a')
+    const {agent: agentB} = makeFakeAgent('did:plc:b')
+
+    const clientA1 = agentToLexClient(agentA)
+    const clientA2 = agentToLexClient(agentA)
+    const clientB = agentToLexClient(agentB)
+
+    expect(clientA1).toBeInstanceOf(Client)
+    expect(clientA1).toBe(clientA2)
+    expect(clientA1).not.toBe(clientB)
+  })
+})
diff --git a/src/state/session/clients.ts b/src/state/session/clients.ts
new file mode 100644
index 0000000000..6c4e72bc42
--- /dev/null
+++ b/src/state/session/clients.ts
@@ -0,0 +1,72 @@
+import {type AtpAgent} from '@atproto/api'
+import {Client} from '@atproto/lex-client'
+
+import {PUBLIC_BSKY_SERVICE} from '#/lib/constants'
+
+/**
+ * Stable per-agent cache of lex `Client` instances. We never reuse an
+ * `AtpAgent` (the session provider disposes the previous one on switch), so a
+ * `WeakMap` keyed on the agent gives us a client whose identity is stable for
+ * the lifetime of that agent. This keeps React Query keys and hook consumers
+ * from churning on every render.
+ */
+const clientForAgent = new WeakMap<AtpAgent, Client>()
+
+/**
+ * Wrap a live {@link AtpAgent} as a lex {@link Client}, bridging the old session
+ * source of truth to the new SDK so features can migrate incrementally.
+ *
+ * The client talks to the agent through the minimal lex `Agent` interface
+ * (`{ did, fetchHandler }`). We deliberately route `fetchHandler` through
+ * `agent.fetchHandler` (the agent's XRPC dispatch layer) rather than
+ * `agent.sessionManager.fetchHandler`:
+ *
+ * - `agent.fetchHandler` (see @atproto/api `agent.js`) is where the agent
+ *   applies its configured `atproto-proxy` header (set via `configureProxy` to
+ *   the appview) and its `atproto-accept-labelers` header, before delegating to
+ *   `sessionManager.fetchHandler` for authorization + token refresh.
+ * - `sessionManager.fetchHandler` (`CredentialSession`) only adds the auth
+ *   token and handles refresh - it does NOT proxy or attach labelers. Wrapping
+ *   it directly would silently drop appview proxying and moderation labelers.
+ *
+ * Because the wrapped agent already applies proxy + labeler headers, we do NOT
+ * pass a `service` option to the `Client` (lex-client only sets `atproto-proxy`
+ * when `service` is provided) and we leave `Client.appLabelers` at its default
+ * empty set. This avoids double-setting either header.
+ *
+ * Results are memoized per-agent so the returned client is referentially stable.
+ */
+export function agentToLexClient(agent: AtpAgent): Client {
+  const cached = clientForAgent.get(agent)
+  if (cached) {
+    return cached
+  }
+  const client = new Client({
+    get did() {
+      return agent.did
+    },
+    fetchHandler: (path, init) => agent.fetchHandler(path, init),
+  })
+  clientForAgent.set(agent, client)
+  return client
+}
+
+/**
+ * Lazily-constructed unauthenticated client pointed at the public appview. It
+ * hits {@link PUBLIC_BSKY_SERVICE} directly, mirroring `createPublicAgent`'s
+ * service URL, so no proxying is required.
+ */
+let publicClient: Client | undefined
+
+function getPublicLexClient(): Client {
+  publicClient ??= new Client(PUBLIC_BSKY_SERVICE)
+  return publicClient
+}
+
+/**
+ * Unauthenticated lex {@link Client} for public appview reads. A process-wide
+ * singleton, so its identity is stable across renders.
+ */
+export function usePublicLexClient(): Client {
+  return getPublicLexClient()
+}
diff --git a/src/state/session/index.tsx b/src/state/session/index.tsx
index fd31261a9d..232e72af69 100644
--- a/src/state/session/index.tsx
+++ b/src/state/session/index.tsx
@@ -9,6 +9,7 @@ import {
   useSyncExternalStore,
 } from 'react'
 import {type AtpAgent, type AtpSessionEvent} from '@atproto/api'
+import {type Client} from '@atproto/lex-client'
 
 import * as persisted from '#/state/persisted'
 import {useCloseAllActiveElements} from '#/state/util'
@@ -26,6 +27,7 @@ import {
 } from './agent'
 import {type Action, getInitialState, reducer, type State} from './reducer'
 export {isSignupQueued} from './util'
+import {agentToLexClient} from './clients'
 import {addSessionDebugLog} from './logging'
 export type {SessionAccount} from '#/state/session/types'
 
@@ -460,3 +462,14 @@ export function useAgent(): AtpAgent {
   }
   return agent
 }
+
+/**
+ * Authenticated lex {@link Client} wrapping the current session agent. Stable
+ * per-agent, so it only changes identity when the active account changes.
+ *
+ * @see agentToLexClient for how the AtpAgent is bridged to the lex Client.
+ */
+export function useLexClient(): Client {
+  const agent = useAgent()
+  return agentToLexClient(agent)
+}
diff --git a/src/types/bsky/__tests__/index.test.ts b/src/types/bsky/__tests__/index.test.ts
new file mode 100644
index 0000000000..f108ebc98a
--- /dev/null
+++ b/src/types/bsky/__tests__/index.test.ts
@@ -0,0 +1,163 @@
+import {AppBskyFeedPost} from '@atproto/api'
+
+import {app} from '#/lexicons'
+import * as bsky from '#/types/bsky'
+
+const now = () => new Date().toISOString()
+
+/**
+ * A structurally valid `app.bsky.feed.post` record.
+ */
+const validPost = {
+  $type: 'app.bsky.feed.post',
+  text: 'hello world',
+  createdAt: now(),
+}
+
+/**
+ * Right `$type`, but the body is invalid (`text` is not a string, `createdAt`
+ * is not a datetime). Passes a `$type`-only guard, fails full validation.
+ */
+const invalidPost = {
+  $type: 'app.bsky.feed.post',
+  text: 123,
+  createdAt: 'not-a-datetime',
+}
+
+/**
+ * A different record type entirely - should fail even the fast guard.
+ */
+const wrongType = {
+  $type: 'app.bsky.feed.like',
+  subject: {uri: 'at://x', cid: 'y'},
+  createdAt: now(),
+}
+
+describe('types/bsky new-world helpers (#/lexicons)', () => {
+  describe('isType (fast, $type-only)', () => {
+    it('accepts a valid record', () => {
+      expect(bsky.isType(app.bsky.feed.post, validPost)).toBe(true)
+    })
+
+    it('rejects a $type mismatch', () => {
+      expect(bsky.isType(app.bsky.feed.post, wrongType)).toBe(false)
+    })
+
+    it('accepts an invalid body that has the right $type (dangerous semantics)', () => {
+      // Mirrors the old `dangerousIsType`: only the `$type` is checked, so a
+      // structurally invalid record still passes.
+      expect(bsky.isType(app.bsky.feed.post, invalidPost)).toBe(true)
+    })
+
+    it('accepts a schema passed as its namespace module or its main schema', () => {
+      expect(bsky.isType(app.bsky.feed.post, validPost)).toBe(true)
+      expect(bsky.isType(app.bsky.feed.post.main, validPost)).toBe(true)
+    })
+
+    it('returns false (does not throw) for null and undefined', () => {
+      // Mirrors the old `dangerousIsType`/`is$typed` behavior - call sites
+      // pass e.g. `post.record` which may be undefined.
+      expect(bsky.isType(app.bsky.feed.post, null)).toBe(false)
+      expect(bsky.isType(app.bsky.feed.post, undefined)).toBe(false)
+      expect(bsky.isType(app.bsky.feed.post, 'string')).toBe(false)
+    })
+
+    it('requires a present $type for typed-object def schemas', () => {
+      /*
+       * The generated TypedObjectSchema.isTypeOf treats a missing $type as a
+       * match (maybe-typed semantics). Our helper must NOT: when
+       * discriminating unions by $type, an object without $type would
+       * otherwise satisfy every branch.
+       */
+      expect(bsky.isType(app.bsky.feed.defs.postView, {foo: 1})).toBe(false)
+      expect(bsky.isType(app.bsky.feed.defs.postView, {})).toBe(false)
+      expect(
+        bsky.isType(app.bsky.feed.defs.postView, {
+          $type: 'app.bsky.feed.defs#postView',
+        }),
+      ).toBe(true)
+    })
+  })
+
+  describe('matches (full validation guard)', () => {
+    it('accepts a valid record', () => {
+      expect(bsky.matches(app.bsky.feed.post, validPost)).toBe(true)
+    })
+
+    it('rejects a $type mismatch', () => {
+      expect(bsky.matches(app.bsky.feed.post, wrongType)).toBe(false)
+    })
+
+    it('rejects an invalid body even though the $type matches', () => {
+      expect(bsky.matches(app.bsky.feed.post, invalidPost)).toBe(false)
+    })
+  })
+
+  describe('safeParse (full validation, no throw)', () => {
+    it('succeeds and returns the value for a valid record', () => {
+      const result = bsky.safeParse(app.bsky.feed.post, validPost)
+      expect(result.success).toBe(true)
+      if (result.success) {
+        expect(result.value.text).toBe('hello world')
+      }
+    })
+
+    it('fails with a reason for an invalid record', () => {
+      const result = bsky.safeParse(app.bsky.feed.post, invalidPost)
+      expect(result.success).toBe(false)
+      if (!result.success) {
+        expect(result.reason).toBeDefined()
+      }
+    })
+  })
+
+  describe('parse (full validation, throws)', () => {
+    it('returns the typed value for a valid record', () => {
+      const record = bsky.parse(app.bsky.feed.post, validPost)
+      expect(record.text).toBe('hello world')
+    })
+
+    it('throws for an invalid record', () => {
+      expect(() => bsky.parse(app.bsky.feed.post, invalidPost)).toThrow()
+    })
+  })
+})
+
+describe('types/bsky legacy helpers (@atproto/api) still work', () => {
+  it('dangerousIsType accepts the right $type without validating the body', () => {
+    expect(
+      bsky.dangerousIsType<AppBskyFeedPost.Record>(
+        validPost,
+        AppBskyFeedPost.isRecord,
+      ),
+    ).toBe(true)
+    // Right $type, invalid body - still passes the fast guard.
+    expect(
+      bsky.dangerousIsType<AppBskyFeedPost.Record>(
+        invalidPost,
+        AppBskyFeedPost.isRecord,
+      ),
+    ).toBe(true)
+    expect(
+      bsky.dangerousIsType<AppBskyFeedPost.Record>(
+        wrongType,
+        AppBskyFeedPost.isRecord,
+      ),
+    ).toBe(false)
+  })
+
+  it('validate fully validates the body', () => {
+    expect(
+      bsky.validate<AppBskyFeedPost.Record>(
+        validPost,
+        AppBskyFeedPost.validateRecord,
+      ),
+    ).toBe(true)
+    expect(
+      bsky.validate<AppBskyFeedPost.Record>(
+        invalidPost,
+        AppBskyFeedPost.validateRecord,
+      ),
+    ).toBe(false)
+  })
+})
diff --git a/src/types/bsky/index.ts b/src/types/bsky/index.ts
index d482f9515b..5e168858cb 100644
--- a/src/types/bsky/index.ts
+++ b/src/types/bsky/index.ts
@@ -1,4 +1,16 @@
-import {type ValidationResult} from '@atproto/lexicon'
+import {
+  getMain,
+  type InferInput,
+  type InferOutput,
+  type Main,
+  type ParseOptions,
+  type RecordSchema,
+  type Schema,
+  type TypedObjectSchema,
+  type ValidateOptions,
+  type ValidationResult,
+} from '@atproto/lex'
+import {type ValidationResult as LegacyValidationResult} from '@atproto/lexicon'
 
 export * as post from '#/types/bsky/post'
 export * as profile from '#/types/bsky/profile'
@@ -45,7 +57,157 @@ export function dangerousIsType<R extends {$type?: string}>(
  */
 export function validate<R extends {$type?: string}>(
   record: unknown,
-  validator: (v: unknown) => ValidationResult<R>,
+  validator: (v: unknown) => LegacyValidationResult<R>,
 ): record is R {
   return validator(record).success
 }
+
+/*
+ * New-world helpers (below) operate on the generated lexicon schema objects
+ * from '#/lexicons', replacing the `@atproto/api`-based helpers above.
+ *
+ * The old helpers take a record plus a standalone `is*`/`validate*` function
+ * (e.g. `AppBskyFeedPost.isRecord`). The new codegen instead attaches the
+ * validation surface directly to each schema, so these helpers take the schema
+ * object itself:
+ *
+ * ```ts
+ * import {app} from '#/lexicons'
+ * import * as bsky from '#/types/bsky'
+ *
+ * // old: bsky.dangerousIsType(v, AppBskyFeedPost.isRecord)
+ * bsky.isType(app.bsky.feed.post, v)
+ *
+ * // old: bsky.validate(v, AppBskyFeedPost.validateRecord)
+ * bsky.matches(app.bsky.feed.post, v)
+ * ```
+ *
+ * Every generated namespace module (e.g. `app.bsky.feed.post`) re-exports its
+ * `main` schema, and bare defs (e.g. `app.bsky.feed.defs.postView`) are schema
+ * objects directly. Both forms are accepted here - `getMain` unwraps a module
+ * to its `main` schema and passes a bare schema through unchanged - so call
+ * sites can pass whichever is in scope.
+ */
+
+/**
+ * A generated lexicon schema that carries a `$type` and therefore supports the
+ * fast, `$type`-only {@link isType} check: a record schema (`app.bsky.feed.post`)
+ * or a typed-object def schema (`app.bsky.feed.defs.postView`).
+ */
+type TypedSchema = RecordSchema | TypedObjectSchema
+
+/**
+ * Fast type checking without full schema validation, for use with data we
+ * trust, or for non-critical path use cases. This only compares the `$type`
+ * string; it does NOT assert the rest of the object matches the schema. An
+ * invalid record with the right `$type` will pass.
+ *
+ * This is the '#/lexicons' equivalent of {@link dangerousIsType}. For full
+ * validation of the object schema, use {@link matches}, {@link parse}, or
+ * {@link safeParse} from this same file.
+ *
+ * Usage:
+ * ```ts
+ * import {app} from '#/lexicons'
+ * import * as bsky from '#/types/bsky'
+ *
+ * if (bsky.isType(app.bsky.feed.post, item)) {
+ *   // `item` is narrowed to the post record type here
+ * }
+ * ```
+ */
+export function isType<S extends TypedSchema>(
+  schema: Main<S>,
+  value: unknown,
+): value is InferInput<S> {
+  /*
+   * Deliberately NOT delegating to the schema's `isTypeOf`: the generated
+   * `TypedObjectSchema.isTypeOf` treats a MISSING `$type` as a match
+   * (maybe-typed semantics), which would let any plain object satisfy any
+   * def-schema check and break `$type`-discriminated unions. The old
+   * `dangerousIsType` required a present, matching `$type`, and so do we.
+   * The nullish/object guard also mirrors the old `is$typed` behavior of
+   * returning false (not throwing) for null/undefined input.
+   */
+  return (
+    value != null &&
+    typeof value === 'object' &&
+    (value as {$type?: unknown}).$type === getMain(schema).$type
+  )
+}
+
+/**
+ * Fully validates the object against the schema (strict, no coercion), which
+ * has a performance cost, and narrows the value on success.
+ *
+ * This is the '#/lexicons' equivalent of {@link validate}. For faster checks
+ * with data we trust, like that from our app view, use {@link isType} from this
+ * same file.
+ *
+ * Usage:
+ * ```ts
+ * import {app} from '#/lexicons'
+ * import * as bsky from '#/types/bsky'
+ *
+ * if (bsky.matches(app.bsky.feed.post, item)) {
+ *   // `item` is narrowed to the post record type here
+ * }
+ * ```
+ */
+export function matches<S extends Schema>(
+  schema: Main<S>,
+  value: unknown,
+  options?: ValidateOptions,
+): value is InferInput<S> {
+  return getMain(schema).matches(value, options)
+}
+
+/**
+ * Fully validates and parses the value against the schema, returning the typed
+ * value or throwing an `LexValidationError` on failure. Parsing may apply
+ * schema transformations such as default values.
+ *
+ * Prefer {@link safeParse} where you want to branch on failure without a
+ * try/catch, or {@link matches} where you only need a type guard.
+ *
+ * Usage:
+ * ```ts
+ * import {app} from '#/lexicons'
+ * import * as bsky from '#/types/bsky'
+ *
+ * const record = bsky.parse(app.bsky.feed.post, item) // typed, or throws
+ * ```
+ */
+export function parse<S extends Schema>(
+  schema: Main<S>,
+  value: unknown,
+  options?: ParseOptions,
+): InferOutput<S> {
+  return getMain(schema).parse(value, options)
+}
+
+/**
+ * Fully validates and parses the value against the schema, returning a
+ * discriminated `ValidationResult` instead of throwing. Parsing may apply
+ * schema transformations such as default values.
+ *
+ * Usage:
+ * ```ts
+ * import {app} from '#/lexicons'
+ * import * as bsky from '#/types/bsky'
+ *
+ * const result = bsky.safeParse(app.bsky.feed.post, item)
+ * if (result.success) {
+ *   // `result.value` is the typed post record
+ * } else {
+ *   // `result.reason` is the LexValidationError
+ * }
+ * ```
+ */
+export function safeParse<S extends Schema>(
+  schema: Main<S>,
+  value: unknown,
+  options?: ParseOptions,
+): ValidationResult<InferOutput<S>> {
+  return getMain(schema).safeParse(value, options)
+}