fix(market): drop structured price field from trader's market posts

src/trader/intent-engine.ts

@@ -891,18 +891,23 @@ export function createIntentEngine(deps: IntentEngineDeps): IntentEngine {
       intents.set(intentId, draftRecord);
 
       // Transition DRAFT → ACTIVE (validates transition)
-      // Build description for market posting
+      // Build description for market posting.
+      //
+      // The market-api is a semantic-search database: counterparties
+      // discover us by matching the description. We do NOT send a
+      // structured `price` field — the description embeds all the
+      // structured rate/volume info already (encodeDescription is the
+      // canonical TIP-0 form, parseDescription extracts the fields on
+      // the receiving side). Sending price separately is redundant AND
+      // hits an unhandled exception in the deployed market-api server
+      // (HTTP 500 with HTML body) — sphere-sdk#475 §6 surfaced this.
+      //
+      // category + currency are still sent because they're useful
+      // semantic tags for the search index (and the server accepts
+      // strings there without issue). The `price` field stays
+      // OPTIONAL in PostIntentRequest for callers with a separate
+      // numeric pricing flow — the trader doesn't.
       const description = encodeDescription(tradingIntent);
-      // Bigint midpoint of the rate band, serialized to a decimal
-      // string for the wire. NEVER cast to Number — for a typical
-      // 18-decimal quote asset, the midpoint of a 0.08–0.12 band is
-      // 1e17 which is past Number.MAX_SAFE_INTEGER (≈9e15). Coercing
-      // loses precision, the market-api server rejects with HTTP 500,
-      // and the trader logs only an opaque status code. The SDK's
-      // PostIntentRequest.price field is `string` for exactly this
-      // reason (see sphere-sdk PR #483); pass `.toString()` through
-      // and the JSON serialization is correct end-to-end.
-      const midpointRate = (rateMin + rateMax) / 2n;
       const expiresInDays = Math.max(
         1,
         Math.ceil((expiryMs - nowMs()) / 86_400_000),
@@ -914,7 +919,6 @@ export function createIntentEngine(deps: IntentEngineDeps): IntentEngine {
           description,
           intentType: params.direction,
           category: `${params.base_asset}/${params.quote_asset}`,
-          price: midpointRate.toString(),
           currency: params.quote_asset,
           // Prefer @nametag for contactHandle — it resolves faster than DIRECT://
           // which requires a binding event lookup that may not have propagated yet.

src/trader/types.ts

@@ -269,15 +269,15 @@ export interface MarketPostRequest {
   readonly intentType: 'buy' | 'sell';
   readonly category: string;
   /**
-   * Price as a decimal-string bigint in the quote currency's smallest
-   * units. Same convention as token amounts in sphere-sdk (TXF amount
-   * fields, transfer payloads): internally bigint, over the wire
-   * decimal-string. Avoids JavaScript's `Number` precision loss for
-   * values above 2^53 (an 18-decimal coin hits that ceiling around
-   * 0.09 in human units). See sphere-sdk PR #483 for the SDK-side
-   * type that aligns with this.
+   * Optional structured price hint (decimal-string bigint in the
+   * quote currency's smallest units). The trader does NOT set this —
+   * the market-api is a semantic-search database, so we let the
+   * description (which encodes the full rate band per TIP-0) be the
+   * source of truth. `price` stays in the shape for callers that have
+   * a single-point pricing use case, but emitting it from the trader
+   * is both redundant and trips the deployed market-api server.
    */
-  readonly price: string;
+  readonly price?: string;
   readonly currency: string;
   readonly contactHandle: string;
   readonly expiresInDays: number;

test/e2e/trader-intent-lifecycle.e2e.test.ts

@@ -249,10 +249,12 @@ describe('E2E: Trader Intent Lifecycle (T1 + T10)', () => {
       expect(postCall.category).toBe('ALPHA/USDC');
       expect(postCall.currency).toBe('USDC');
       expect(postCall.contactHandle).toBe(AGENT_ADDRESS);
-      // Midpoint of 450-500 = 475, serialized as decimal-string bigint
-      // per sphere-sdk PostIntentRequest.price convention (no Number
-      // cast — see trader/intent-engine.ts comment block).
-      expect(postCall.price).toBe('475');
+      // No structured `price` field — the trader leans on the
+      // semantic-search engine in the deployed market-api. The
+      // description (asserted below) already carries the rate band
+      // in TIP-0 form, so a structured price hint would be redundant
+      // (and trips the server). See intent-engine.ts comment block.
+      expect(postCall.price).toBeUndefined();
       // Description must match canonical format
       expect(postCall.description).toContain('Selling 100-1000 ALPHA for USDC');
       expect(postCall.description).toContain('Rate: 450-500 USDC per ALPHA');