diff --git a/apps/server/src/engine/price.ts b/apps/server/src/engine/price.ts
new file mode 100644
index 000000000..9c888471d
--- /dev/null
+++ b/apps/server/src/engine/price.ts
@@ -0,0 +1,10 @@
+// A match is rejected when the next character continues the numeric token
+// (digit, a comma followed by a digit, a decimal dot followed by a digit) or
+// attaches a magnitude/unit letter ($9M, $9k). A sentence comma, slash or
+// other punctuation still ends the price.
+const PRICE_PATTERN = /(?:\$|USD)\s*(\d+(?:,\d{3})*(?:\.\d{1,2})?)(?!\d|[A-Za-z]|,\d|\.\d)/g;
+
+export function matchesPrice(text: string, threshold: number): boolean {
+  const matches = [...text.matchAll(PRICE_PATTERN)];
+  return matches.some((m) => Number(m[1].replace(/,/g, "")) < threshold);
+}
diff --git a/apps/server/src/engine/service.ts b/apps/server/src/engine/service.ts
index 0e071ba87..8eb2ab446 100644
--- a/apps/server/src/engine/service.ts
+++ b/apps/server/src/engine/service.ts
@@ -42,6 +42,7 @@ import {
   pageLines,
   withoutRelativeTimes,
 } from "./page-diff.ts";
+import { matchesPrice } from "./price.ts";
 import { LostLeaseError, type TaskContext, TaskWorker } from "./worker.ts";
 
 const hash = (text: string) => createHash("sha256").update(text).digest("hex");
@@ -1094,7 +1095,7 @@ export class AgentService {
         ? Boolean(previousHash && previousHash !== currentHash)
         : monitor.condition === "contains"
           ? text.toLowerCase().includes(monitor.value.toLowerCase())
-          : this.matchesPrice(text, Number(monitor.value));
+          : matchesPrice(text, Number(monitor.value));
     const previouslyMatched = Boolean(task.state.matched);
     // For change watches, keep the page lines and a relative-time-free fingerprint of the whole text.
     const change = monitor.condition === "change";
@@ -1192,8 +1193,4 @@ export class AgentService {
       plan: task.plan.map((s) => ({ ...s, status: "succeeded" })),
     };
   }
-  private matchesPrice(text: string, threshold: number) {
-    const matches = [...text.matchAll(/(?:\$|USD)\s*(\d+(?:,\d{3})*(?:\.\d{1,2})?)/g)];
-    return matches.some((m) => Number(m[1].replace(/,/g, "")) < threshold);
-  }
 }
diff --git a/tests/monitor-price-token-boundaries.test.ts b/tests/monitor-price-token-boundaries.test.ts
new file mode 100644
index 000000000..e6ae93ee1
--- /dev/null
+++ b/tests/monitor-price-token-boundaries.test.ts
@@ -0,0 +1,60 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { createApp } from "../apps/server/src/app.ts";
+import { matchesPrice } from "../apps/server/src/engine/price.ts";
+import type { AgentNotification } from "../packages/domain/src/agent.ts";
+import { browserFixture } from "./helpers/browser.ts";
+
+const THRESHOLD = 10;
+
+for (const [text, expected, why] of [
+  ["Price: $1,00", false, "truncated thousands group is not a price"],
+  ["Price: $1,0", false, "truncated thousands group is not a price"],
+  ["Price: $9.999", false, "a third decimal digit is not a price"],
+  ["Price: USD 1,00", false, "truncated thousands group is not a price"],
+  ["Price: $9M", false, "a magnitude suffix is not a bare price"],
+  ["Price: $9k", false, "a magnitude suffix is not a bare price"],
+  ["Price: $1,000,00", false, "a second thousands comma is not a price"],
+  ["Price: $1,000", false, "1000 is not under the threshold"],
+  ["Price: $1,000.00", false, "1000 is not under the threshold"],
+  ["Only $5,", true, "a sentence comma still ends the price"],
+  ["Price: $9, limited time", true, "a sentence comma still ends the price"],
+  ["$5, $20", true, "a comma-separated list keeps both prices"],
+  ["Now $9, was $20", true, "the lower price is still found"],
+  ["Price: $9.99/month", true, "a slash still ends the price"],
+  ["Price: $9", true, "a plain price under the threshold matches"],
+] as const) {
+  test(`matchesPrice ${expected ? "matches" : "rejects"} ${JSON.stringify(text)} (${why})`, () => {
+    assert.equal(matchesPrice(text, THRESHOLD), expected);
+  });
+}
+
+test("price watch reaches the worker outcome path through matchesPrice", async (t) => {
+  const url = "https://example.com/product";
+  const fixture = await browserFixture(t, (path, body) => ({
+    data: path.endsWith("/read")
+      ? { url, title: "Product", text: "Only $5, today only", truncated: false }
+      : {
+          id: body.id,
+          title: "Product",
+          url,
+          status: "active",
+          updatedAt: new Date().toISOString(),
+        },
+  }));
+  const server = await createApp(fixture.db, fixture.config);
+  t.after(() => server.agent.stop());
+  const owner = "price-boundary-user";
+  const monitor = await server.agent.createMonitor(owner, {
+    title: "Price watch",
+    url,
+    condition: "price_below",
+    value: "10",
+  });
+  await server.agent.worker.tick();
+  const task = await server.agent.getTask(owner, monitor.taskId);
+  assert.equal(task.status, "scheduled");
+  assert.equal(task.state.matched, true);
+  const notifications = await fixture.db.list<AgentNotification>(owner, "notifications");
+  assert.equal(notifications.filter((entry) => entry.taskId === task.id).length, 1);
+});