fix(interface): bound a turn prompt as content, not as metadata

packages/agent-interface/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@tangle-network/agent-interface",
-  "version": "2.6.1",
+  "version": "2.7.0",
   "type": "module",
   "sideEffects": false,
   "license": "MIT",

packages/agent-interface/src/environment-interactive-control.ts

@@ -8,6 +8,7 @@ import {
 } from "./agent-execution-preparation-receipt.js";
 import {
   boundedIdentifierSchema,
+  boundedEventContentStringSchema,
   boundedStringSchema,
 } from "./contract-limits.js";
 import {
@@ -546,7 +547,13 @@ const AgentInteractiveSessionPromptCommandMaterialSchema = z
     operationId: boundedIdentifierSchema,
     ref: AgentInteractiveSessionRefSchema,
     control: AgentInteractiveSessionControlClaimSchema,
-    prompt: boundedStringSchema.min(1),
+    // Content, not metadata: see environment-runtime.ts.
+    // Content, not metadata: see environment-runtime.ts. `boundedEventContentStringSchema` is a
+    // custom schema and carries no `.min`, so the non-empty requirement is kept as a refinement —
+    // an interactive prompt with nothing in it is still refused.
+    prompt: boundedEventContentStringSchema.refine((value) => value.length >= 1, {
+      message: "interactive prompt must not be empty",
+    }),
   })
   .superRefine((command, refinement) => {
     if (!agentInteractiveSessionControlClaimMatchesRef(command.ref, command.control)) {

packages/agent-interface/src/environment-runtime.ts

@@ -55,7 +55,12 @@ export interface AgentTurnInput {
 }
 
 export const AgentTurnInputSchema = z.strictObject({
-  prompt: boundedStringSchema.optional(),
+  // A prompt is what the agent is asked to do, so it is CONTENT: its size is set by the work,
+  // not by the protocol. Held to the metadata bound it capped a manager's brief at 16,384
+  // characters, which refused a director handing a checker a 27 KB patch to re-verify a measured
+  // result (agent-sdk#313). Refusal is still right here — a silently shortened instruction is
+  // worse than none — so only the ceiling moves.
+  prompt: boundedEventContentStringSchema.optional(),
   parts: z.array(InputPartSchema).max(CONTRACT_MAX_ARRAY_LENGTH).optional(),
   sessionId: boundedIdentifierSchema.optional(),
   model: boundedIdentifierSchema.optional(),

packages/agent-interface/src/leaf-modules.test.ts

@@ -555,6 +555,18 @@ describe("interface split leaf modules", () => {
     expect(() =>
       AgentTurnInputSchema.parse({ prompt: "x", context: { huge: "x".repeat(CONTRACT_MAX_STRING_LENGTH + 1) } }),
     ).toThrow();
+    // A prompt is CONTENT: its size is set by the work, not by the protocol. Held to the metadata
+    // bound it capped a manager's brief at 16,384 characters, which refused a director handing a
+    // checker a 27 KB patch to re-verify a measured result (agent-sdk#313). `context` above keeps
+    // the metadata bound, because that is material describing the turn rather than the ask itself.
+    expect(() =>
+      AgentTurnInputSchema.parse({ prompt: "x".repeat(CONTRACT_MAX_STRING_LENGTH + 1) }),
+    ).not.toThrow();
+    expect(() => AgentTurnInputSchema.parse({ prompt: "x".repeat(200_000) })).not.toThrow();
+    // The content bound still governs it, so an unbounded prompt is still refused.
+    expect(() =>
+      AgentTurnInputSchema.parse({ prompt: "x".repeat(2 * 1024 * 1024) }),
+    ).toThrow();
     for (const usageMode of ["delta", "cumulative"]) {
       expect(AgentTurnResultSchema.parse({
         text: "x", success: true,

packages/agent-interface/src/portable-context-continuation.ts

@@ -5,7 +5,8 @@ import {
   type AgentExactRunControlRef,
 } from "./runtime-control.js";
 import { idSchema, InputPartSchema, jsonRecordSchema, sha256DigestSchema, wireDigest } from "./portable-context-shared.js";
-import { boundedStringSchema, CONTRACT_MAX_ARRAY_LENGTH } from "./contract-limits.js";
+import { boundedEventContentStringSchema,
+  boundedStringSchema, CONTRACT_MAX_ARRAY_LENGTH } from "./contract-limits.js";
 
 export const NativeContextBoundarySchema = z
   .discriminatedUnion("kind", [
@@ -78,7 +79,8 @@ export interface NativeContextContinuationTurn {
 }
 
 export const NativeContextContinuationTurnSchema = z.strictObject({
-  prompt: boundedStringSchema.optional(),
+  // Content, not metadata: see environment-runtime.ts.
+  prompt: boundedEventContentStringSchema.optional(),
   parts: z.array(InputPartSchema).max(CONTRACT_MAX_ARRAY_LENGTH).optional(),
   model: idSchema.optional(),
   context: jsonRecordSchema.optional(),

packages/agent-interface/src/runtime-control.ts

@@ -399,7 +399,8 @@ const partSchema = z.discriminatedUnion("type", [
   z.strictObject({
     ...partBase,
     type: z.literal("subtask"),
-    prompt: boundedStringSchema,
+    // Content, not metadata: see environment-runtime.ts.
+    prompt: boundedEventContentStringSchema,
     description: boundedStringSchema,
     agent: stableIdSchema,
   }),