diff --git a/packages/interface/src/capability.ts b/packages/interface/src/capability.ts
index ab9fde43..d35f5b72 100644
--- a/packages/interface/src/capability.ts
+++ b/packages/interface/src/capability.ts
@@ -335,10 +335,6 @@ export interface ParsedCapability<
   nb: C
 }
 
-export type InferCaveats<C> = Optionalize<{
-  [K in keyof C]: C[K] extends Reader<infer T, unknown, infer _> ? T : never
-}>
-
 export interface Descriptor<
   A extends Ability,
   R extends URI,
diff --git a/packages/server/src/api.ts b/packages/server/src/api.ts
index 40287dad..6b027ccf 100644
--- a/packages/server/src/api.ts
+++ b/packages/server/src/api.ts
@@ -1,5 +1,5 @@
 import * as API from '@ucanto/interface'
-import { InferCaveats, CanIssue, ParsedCapability } from '@ucanto/interface'
+import { CanIssue, ParsedCapability } from '@ucanto/interface'
 
 export * from '@ucanto/interface'
 
@@ -23,8 +23,8 @@ export interface ProviderContext<
   R extends API.URI = API.URI,
   C extends API.Caveats = API.Caveats
 > {
-  capability: API.ParsedCapability<A, R, API.InferCaveats<C>>
-  invocation: API.Invocation<API.Capability<A, R, API.InferCaveats<C>>>
+  capability: API.ParsedCapability<A, R, C>
+  invocation: API.Invocation<API.Capability<A, R, C>>
 
   context: API.InvocationContext
 }
diff --git a/packages/server/src/handler.js b/packages/server/src/handler.js
index 5f1bcbf3..b0a1d945 100644
--- a/packages/server/src/handler.js
+++ b/packages/server/src/handler.js
@@ -6,15 +6,15 @@ import { access } from '@ucanto/validator'
  * @template {API.URI} R
  * @template {API.Caveats} C
  * @template {unknown} U
- * @param {API.CapabilityParser<API.Match<API.ParsedCapability<A, R, API.InferCaveats<C>>>>} capability
- * @param {(input:API.ProviderInput<API.ParsedCapability<A, R, API.InferCaveats<C>>>) => API.Await<U>} handler
- * @returns {API.ServiceMethod<API.Capability<A, R, API.InferCaveats<C>>, Exclude<U, {error:true}>, Exclude<U, Exclude<U, {error:true}>>>}
+ * @param {API.CapabilityParser<API.Match<API.ParsedCapability<A, R, C>>>} capability
+ * @param {(input:API.ProviderInput<API.ParsedCapability<A, R, C>>) => API.Await<U>} handler
+ * @returns {API.ServiceMethod<API.Capability<A, R, C>, Exclude<U, {error:true}>, Exclude<U, Exclude<U, {error:true}>>>}
  */
 
 export const provide =
   (capability, handler) =>
   /**
-   * @param {API.Invocation<API.Capability<A, R, API.InferCaveats<C>>>} invocation
+   * @param {API.Invocation<API.Capability<A, R, C>>} invocation
    * @param {API.InvocationContext} options
    */
   async (invocation, options) => {
diff --git a/packages/server/test/server.spec.js b/packages/server/test/server.spec.js
index b2bd53cb..cf518dac 100644
--- a/packages/server/test/server.spec.js
+++ b/packages/server/test/server.spec.js
@@ -5,13 +5,14 @@ import * as CBOR from '@ucanto/transport/cbor'
 import { alice, bob, mallory, service as w3 } from './fixtures.js'
 import * as Service from '../../client/test/service.js'
 import { test, assert } from './test.js'
+import { Schema } from '@ucanto/validator'
 
 const storeAdd = Server.capability({
   can: 'store/add',
   with: Server.URI.match({ protocol: 'did:' }),
-  nb: {
+  nb: Schema.struct({
     link: Server.Link.match().optional(),
-  },
+  }),
   derives: (claimed, delegated) => {
     if (claimed.with !== delegated.with) {
       return new Server.Failure(
@@ -34,9 +35,9 @@ const storeAdd = Server.capability({
 const storeRemove = Server.capability({
   can: 'store/remove',
   with: Server.URI.match({ protocol: 'did:' }),
-  nb: {
+  nb: Schema.struct({
     link: Server.Link.match().optional(),
-  },
+  }),
   derives: (claimed, delegated) => {
     if (claimed.with !== delegated.with) {
       return new Server.Failure(
diff --git a/packages/server/test/service/store.js b/packages/server/test/service/store.js
index 75f8c5d4..e67f0f15 100644
--- a/packages/server/test/service/store.js
+++ b/packages/server/test/service/store.js
@@ -4,13 +4,14 @@ import { provide } from '../../src/handler.js'
 import * as API from './api.js'
 import * as Access from './access.js'
 import { service as issuer } from '../fixtures.js'
+import { Schema } from '@ucanto/validator/src/lib.js'
 
 const addCapability = Server.capability({
   can: 'store/add',
   with: Server.URI.match({ protocol: 'did:' }),
-  nb: {
+  nb: Schema.struct({
     link: Server.Link.match().optional(),
-  },
+  }),
   derives: (claimed, delegated) => {
     if (claimed.with !== delegated.with) {
       return new Server.Failure(
@@ -34,9 +35,9 @@ const addCapability = Server.capability({
 const removeCapability = Server.capability({
   can: 'store/remove',
   with: Server.URI.match({ protocol: 'did:' }),
-  nb: {
+  nb: Schema.struct({
     link: Server.Link.match().optional(),
-  },
+  }),
   derives: (claimed, delegated) => {
     if (claimed.with !== delegated.with) {
       return new Server.Failure(