refactor(sdk): slim PolicyEngine to check-only, add policy evaluation

packages/core/execution/src/engine.ts

@@ -126,6 +126,11 @@ export const formatPausedExecution = (
       interaction: {
         kind: req._tag === "UrlElicitation" ? "url" : "form",
         message: req.message,
+        ...(paused.elicitationContext.approval
+          ? {
+              approval: paused.elicitationContext.approval,
+            }
+          : {}),
         ...(req._tag === "UrlElicitation" ? { url: req.url } : {}),
         ...(req._tag === "FormElicitation" ? { requestedSchema: req.requestedSchema } : {}),
       },

packages/core/sdk/src/elicitation.ts

@@ -1,6 +1,6 @@
 import { Effect, Schema } from "effect";
 
-import { ToolId } from "./ids";
+import { PolicyId, ToolId } from "./ids";
 
 // ---------------------------------------------------------------------------
 // Elicitation request — what a tool sends when it needs user input
@@ -44,6 +44,10 @@ export interface ElicitationContext {
   readonly toolId: ToolId;
   readonly args: unknown;
   readonly request: ElicitationRequest;
+  readonly approval?: {
+    readonly source: "policy" | "annotation";
+    readonly matchedPolicyId?: PolicyId;
+  };
 }
 
 /**

packages/core/sdk/src/errors.ts

@@ -34,3 +34,10 @@ export class PolicyDeniedError extends Schema.TaggedError<PolicyDeniedError>()(
     reason: Schema.String,
   },
 ) {}
+
+export class PolicyNotFoundError extends Schema.TaggedError<PolicyNotFoundError>()(
+  "PolicyNotFoundError",
+  {
+    policyId: PolicyId,
+  },
+) {}

packages/core/sdk/src/executor.ts

@@ -11,15 +11,22 @@ import type {
   InvokeOptions,
 } from "./tools";
 import type { Source, SourceDetectionResult, SourceRegistry } from "./sources";
-import type { Policy, PolicyEngine } from "./policies";
+import type {
+  Policy,
+  PolicyEngine,
+  PolicyDecision,
+  CreatePolicyPayload,
+  UpdatePolicyPayload,
+} from "./policies";
 import type { Scope } from "./scope";
 import type { ExecutorPlugin, PluginExtensions, PluginHandle } from "./plugin";
+import { PolicyDeniedError } from "./errors";
 import type {
   ToolNotFoundError,
   ToolInvocationError,
   SecretNotFoundError,
   SecretResolutionError,
-  PolicyDeniedError,
+  PolicyNotFoundError,
 } from "./errors";
 import {
   FormElicitation,
@@ -64,7 +71,12 @@ export type Executor<TPlugins extends readonly ExecutorPlugin<string, object>[]
 
   readonly policies: {
     readonly list: () => Effect.Effect<readonly Policy[]>;
-    readonly add: (policy: Omit<Policy, "id" | "createdAt">) => Effect.Effect<Policy>;
+    readonly get: (policyId: string) => Effect.Effect<Policy, PolicyNotFoundError>;
+    readonly add: (policy: CreatePolicyPayload) => Effect.Effect<Policy>;
+    readonly update: (
+      policyId: string,
+      patch: UpdatePolicyPayload,
+    ) => Effect.Effect<Policy, PolicyNotFoundError>;
     readonly remove: (policyId: string) => Effect.Effect<boolean>;
   };
 
@@ -120,6 +132,29 @@ export const createExecutor = <
   Effect.gen(function* () {
     const { scope, tools, sources, secrets, policies, plugins = [] } = config;
 
+    const runApproval = (
+      decision: PolicyDecision,
+      toolId: ToolId,
+      args: unknown,
+      options: InvokeOptions,
+      message: string,
+      source: "policy" | "annotation",
+    ) => {
+      const handler = resolveElicitationHandler(options);
+      return handler({
+        toolId,
+        args,
+        request: new FormElicitation({
+          message,
+          requestedSchema: {},
+        }),
+        approval: {
+          source,
+          ...(decision.matchedPolicyId ? { matchedPolicyId: decision.matchedPolicyId } : {}),
+        },
+      });
+    };
+
     // Initialize all plugins
     const handles = new Map<string, PluginHandle<object>>();
     const extensions: Record<string, object> = {};
@@ -146,20 +181,53 @@ export const createExecutor = <
         invoke: (toolId: string, args: unknown, options: InvokeOptions) => {
           const tid = toolId as ToolId;
           return Effect.gen(function* () {
-            yield* policies.check({ scopeId: scope.id, toolId: tid });
+            const decision = yield* policies.check({ scopeId: scope.id, toolId: tid });
+
+            if (decision.kind === "deny") {
+              return yield* new PolicyDeniedError({
+                policyId: decision.matchedPolicyId as PolicyId,
+                toolId: tid,
+                reason: decision.reason,
+              });
+            }
+
+            if (decision.kind === "require_interaction") {
+              const response = yield* runApproval(
+                decision,
+                tid,
+                args,
+                options,
+                decision.reason,
+                "policy",
+              );
+              if (response.action !== "accept") {
+                return yield* new ElicitationDeclinedError({
+                  toolId: tid,
+                  action: response.action,
+                });
+              }
+              return yield* tools.invoke(tid, args, options);
+            }
+
+            if (decision.kind === "allow") {
+              return yield* tools.invoke(tid, args, options);
+            }
 
             // Dynamically resolve annotations from the plugin
             const annotations = yield* tools.resolveAnnotations(tid);
             if (annotations?.requiresApproval) {
-              const handler = resolveElicitationHandler(options);
-              const response = yield* handler({
-                toolId: tid,
+              const response = yield* runApproval(
+                {
+                  kind: "fallback",
+                  matchedPolicyId: null,
+                  reason: annotations.approvalDescription ?? `Approve ${toolId}?`,
+                } as PolicyDecision,
+                tid,
                 args,
-                request: new FormElicitation({
-                  message: annotations.approvalDescription ?? `Approve ${toolId}?`,
-                  requestedSchema: {},
-                }),
-              });
+                options,
+                annotations.approvalDescription ?? `Approve ${toolId}?`,
+                "annotation",
+              );
               if (response.action !== "accept") {
                 return yield* new ElicitationDeclinedError({
                   toolId: tid,
@@ -182,8 +250,11 @@ export const createExecutor = <
 
       policies: {
         list: () => policies.list(scope.id),
-        add: (policy: Omit<Policy, "id" | "createdAt">) =>
+        get: (policyId: string) => policies.get(policyId as PolicyId),
+        add: (policy: CreatePolicyPayload) =>
           policies.add({ ...policy, scopeId: scope.id }),
+        update: (policyId: string, patch: UpdatePolicyPayload) =>
+          policies.update(policyId as PolicyId, patch),
         remove: (policyId: string) => policies.remove(policyId as PolicyId),
       },
 

packages/core/sdk/src/in-memory/policy-engine.ts

@@ -1,23 +1,47 @@
 import { Effect } from "effect";
 
 import { ScopeId, PolicyId } from "../ids";
-import type { Policy, PolicyCheckInput } from "../policies";
+import { PolicyNotFoundError } from "../errors";
+import { evaluatePolicyDecision, sortPoliciesByPrecedence } from "../policy-eval";
+import { Policy } from "../policies";
+import type { CreatePolicyInput, PolicyCheckInput, UpdatePolicyPayload } from "../policies";
 
 export const makeInMemoryPolicyEngine = () => {
   const policies = new Map<string, Policy>();
   let counter = 0;
 
   return {
     list: (scopeId: ScopeId) =>
-      Effect.succeed([...policies.values()].filter((p) => p.scopeId === scopeId)),
-    check: (_input: PolicyCheckInput) => Effect.void,
-    add: (policy: Omit<Policy, "id" | "createdAt">) =>
+      Effect.succeed(sortPoliciesByPrecedence([...policies.values()].filter((p) => p.scopeId === scopeId))),
+    get: (policyId: PolicyId) =>
+      Effect.fromNullable(policies.get(policyId)).pipe(
+        Effect.mapError(() => new PolicyNotFoundError({ policyId })),
+      ),
+    check: (input: PolicyCheckInput) =>
+      Effect.sync(() => evaluatePolicyDecision([...policies.values()], input)),
+    add: (policy: CreatePolicyInput) =>
       Effect.sync(() => {
-        const id = PolicyId.make(`policy-${++counter}`);
-        const full: Policy = { ...policy, id, createdAt: new Date() };
+        const now = new Date();
+        const id = PolicyId.make(`policy-${Date.now()}-${++counter}`);
+        const full = new Policy({ ...policy, id, createdAt: now, updatedAt: now });
         policies.set(id, full);
         return full;
       }),
+    update: (policyId: PolicyId, patch: UpdatePolicyPayload) =>
+      Effect.gen(function* () {
+        const existing = yield* Effect.fromNullable(policies.get(policyId)).pipe(
+          Effect.mapError(() => new PolicyNotFoundError({ policyId })),
+        );
+        const next = new Policy({
+          ...existing,
+          ...Object.fromEntries(
+            Object.entries(patch).filter(([, value]) => value !== undefined),
+          ),
+          updatedAt: new Date(),
+        });
+        policies.set(policyId, next);
+        return next;
+      }),
     remove: (policyId: PolicyId) => Effect.succeed(policies.delete(policyId)),
   };
 };

packages/core/sdk/src/index.ts

@@ -8,6 +8,7 @@ export {
   SecretNotFoundError,
   SecretResolutionError,
   PolicyDeniedError,
+  PolicyNotFoundError,
 } from "./errors";
 
 // Tools
@@ -49,7 +50,25 @@ export {
 export { SecretRef, SetSecretInput, SecretStore, type SecretProvider } from "./secrets";
 
 // Policies
-export { Policy, PolicyAction, PolicyCheckInput, PolicyEngine } from "./policies";
+export {
+  Policy,
+  PolicyEffect,
+  PolicyApprovalMode,
+  PolicyCheckInput,
+  CreatePolicyPayload,
+  UpdatePolicyPayload,
+  PolicyDecision,
+  PolicyEngine,
+  type CreatePolicyInput,
+} from "./policies";
+export {
+  matchesPolicyPattern,
+  policyLiteralCharCount,
+  policySpecificity,
+  comparePoliciesByPrecedence,
+  sortPoliciesByPrecedence,
+  evaluatePolicyDecision,
+} from "./policy-eval";
 
 // Scope
 export { Scope } from "./scope";

packages/core/sdk/src/policies.ts

@@ -1,35 +1,70 @@
 import { Context, Effect, Schema } from "effect";
 
+import { PolicyNotFoundError } from "./errors";
 import { PolicyId, ScopeId, ToolId } from "./ids";
-import { PolicyDeniedError } from "./errors";
 
-export const PolicyAction = Schema.Literal("allow", "deny", "require_approval");
-export type PolicyAction = typeof PolicyAction.Type;
+export const PolicyEffect = Schema.Literal("allow", "deny");
+export type PolicyEffect = typeof PolicyEffect.Type;
+
+export const PolicyApprovalMode = Schema.Literal("auto", "required");
+export type PolicyApprovalMode = typeof PolicyApprovalMode.Type;
 
 export class Policy extends Schema.Class<Policy>("Policy")({
   id: PolicyId,
   scopeId: ScopeId,
-  name: Schema.String,
-  action: PolicyAction,
-  match: Schema.Struct({
-    toolPattern: Schema.optional(Schema.String),
-    sourceId: Schema.optional(Schema.String),
-  }),
+  toolPattern: Schema.String,
+  effect: PolicyEffect,
+  approvalMode: PolicyApprovalMode,
   priority: Schema.Number,
+  enabled: Schema.Boolean,
   createdAt: Schema.DateFromNumber,
+  updatedAt: Schema.DateFromNumber,
 }) {}
 
 export class PolicyCheckInput extends Schema.Class<PolicyCheckInput>("PolicyCheckInput")({
   scopeId: ScopeId,
   toolId: ToolId,
 }) {}
 
+export const CreatePolicyPayload = Schema.Struct({
+  toolPattern: Schema.String,
+  effect: PolicyEffect,
+  approvalMode: PolicyApprovalMode,
+  priority: Schema.Number,
+  enabled: Schema.Boolean,
+});
+export type CreatePolicyPayload = typeof CreatePolicyPayload.Type;
+
+export type CreatePolicyInput = CreatePolicyPayload & {
+  readonly scopeId: ScopeId;
+};
+
+export const UpdatePolicyPayload = Schema.Struct({
+  toolPattern: Schema.optional(Schema.String),
+  effect: Schema.optional(PolicyEffect),
+  approvalMode: Schema.optional(PolicyApprovalMode),
+  priority: Schema.optional(Schema.Number),
+  enabled: Schema.optional(Schema.Boolean),
+});
+export type UpdatePolicyPayload = typeof UpdatePolicyPayload.Type;
+
+export class PolicyDecision extends Schema.Class<PolicyDecision>("PolicyDecision")({
+  kind: Schema.Literal("allow", "deny", "require_interaction", "fallback"),
+  matchedPolicyId: Schema.NullOr(PolicyId),
+  reason: Schema.String,
+}) {}
+
 export class PolicyEngine extends Context.Tag("@executor/sdk/PolicyEngine")<
   PolicyEngine,
   {
     readonly list: (scopeId: ScopeId) => Effect.Effect<readonly Policy[]>;
-    readonly check: (input: PolicyCheckInput) => Effect.Effect<void, PolicyDeniedError>;
-    readonly add: (policy: Omit<Policy, "id" | "createdAt">) => Effect.Effect<Policy>;
+    readonly get: (policyId: PolicyId) => Effect.Effect<Policy, PolicyNotFoundError>;
+    readonly check: (input: PolicyCheckInput) => Effect.Effect<PolicyDecision>;
+    readonly add: (policy: CreatePolicyInput) => Effect.Effect<Policy>;
+    readonly update: (
+      policyId: PolicyId,
+      patch: UpdatePolicyPayload,
+    ) => Effect.Effect<Policy, PolicyNotFoundError>;
     readonly remove: (policyId: PolicyId) => Effect.Effect<boolean>;
   }
 >() {}