diff --git a/src/contract/AGENTS.md b/src/contract/AGENTS.md
index ccdf3da0..86783d79 100644
--- a/src/contract/AGENTS.md
+++ b/src/contract/AGENTS.md
@@ -105,6 +105,9 @@ Three identities:
 - OS constraint: a bare version is exact (string equality). A range is one or more of
   `>=`, `>`, `<=`, `<` + a dotted version, joined by single spaces, or `A - B`.
   `^`, `~`, `*`, `||` and `x` read as a range and are refused.
+- `lease.request` holds an exact `osVersion` to `componentVersionSchema`'s bound (1 to 64
+  characters, no whitespace, control character or `;`, no leading `-`): a downloadable missing
+  runtime installs it as a component.
 - A partial version covers its prefix: `<=26` takes every 26.x, `>26` excludes it. A version that
   is not dotted integers (`Baklava`) matches only exactly.
 - Duration: `500` (ms), `2s`, `3m`, `1h`, `7d`. `undefined` when not one or not a safe integer.
diff --git a/src/contract/operations.test.ts b/src/contract/operations.test.ts
index 8af039f6..17267d3f 100644
--- a/src/contract/operations.test.ts
+++ b/src/contract/operations.test.ts
@@ -248,6 +248,7 @@ describe("component.install input", () => {
     ["a newline", "35\n"],
     ["a control character", "35\u0000"],
     ["starting with '-', like an option", "-35"],
+    ["carrying ';', sdkmanager's package path separator", "35;extras"],
   ])("refuses a version that is %s", (_label, version) => {
     expect(parse(version)).toBe(false);
   });
@@ -261,12 +262,20 @@ describe("lease.request osVersion", () => {
       platform: "ios",
     });
 
-  it.each([["18.4"], ["Baklava"], ["34-ext12"], [">=18"], [">=18 <26"], ["18 - 26"]])(
-    "accepts %s",
-    (osVersion) => {
-      expect(parse(osVersion).success).toBe(true);
-    },
-  );
+  it.each([
+    ["18.4"],
+    ["17.4"],
+    ["34"],
+    ["18.5.1"],
+    ["Baklava"],
+    ["34-ext12"],
+    ["x".repeat(64)],
+    [">=18"],
+    [">=18 <26"],
+    ["18 - 26"],
+  ])("accepts %s", (osVersion) => {
+    expect(parse(osVersion).success).toBe(true);
+  });
 
   it.each([["^18"], ["~18"], ["18.x"], ["18.X"], ["*"], [">=18 || <17"], [""]])(
     "refuses %j with a message naming the accepted forms",
@@ -279,6 +288,28 @@ describe("lease.request osVersion", () => {
       }
     },
   );
+
+  it.each([
+    ["trailing text after a space", "17.0 -foo"],
+    ["a leading '-', like an option", "-1"],
+    ["a ';', sdkmanager's package path separator", "34;extras"],
+    ["more than 64 characters", "x".repeat(65)],
+    ["a control character", "17.4\u0007"],
+    ["a leading space", " 17.4"],
+  ])(
+    "refuses an exact version with %s, naming the bound a component version has",
+    (_label, osVersion) => {
+      const result = parse(osVersion);
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.issues).toHaveLength(1);
+        expect(result.error.issues[0]?.message).toBe(
+          "an exact OS version is 1 to 64 characters, none of them whitespace, a control character or `;`, and does not start with `-`",
+        );
+        expect(result.error.issues[0]?.path).toEqual(["osVersion"]);
+      }
+    },
+  );
 });
 
 describe("lease.request leaseId", () => {
diff --git a/src/contract/operations.ts b/src/contract/operations.ts
index da41b603..4f0c381a 100644
--- a/src/contract/operations.ts
+++ b/src/contract/operations.ts
@@ -151,6 +151,22 @@ export const LEASE_ID_PATTERN = /^[A-Za-z0-9][A-Za-z0-9_-]{0,63}$/;
 
 export const leaseIdSchema = z.string().regex(LEASE_ID_PATTERN);
 
+/**
+ * why: a component's version (`26.4`, `35`) reaches the driver unread and becomes an installer
+ * argument, so its shape is bounded here (safety rule 10): no whitespace or control character, no
+ * `;` (sdkmanager's package path separator), no leading `-` (an option). An exact `osVersion` in
+ * `lease.request` is held to it too, because a downloadable missing runtime installs that string.
+ */
+const componentVersionSchema = z
+  .string()
+  .min(1)
+  .max(64)
+  .regex(/^[^\s\p{Cc};]+$/u, "must contain no whitespace, control character or ';'")
+  .refine((version) => !version.startsWith("-"), "must not start with '-'");
+
+const EXACT_OS_VERSION_BOUND =
+  "an exact OS version is 1 to 64 characters, none of them whitespace, a control character or `;`, and does not start with `-`";
+
 const leaseRequestBaseSchema = z
   .object({
     model: z.string().min(1).optional(),
@@ -281,6 +297,17 @@ function refuseBadOsVersion(): <T extends { readonly osVersion?: string | undefi
         message: parsed.message,
         path: ["osVersion"],
       });
+      return;
+    }
+    if (
+      parsed.constraint.kind === "exact" &&
+      !componentVersionSchema.safeParse(parsed.constraint.version).success
+    ) {
+      context.addIssue({
+        code: "custom",
+        message: EXACT_OS_VERSION_BOUND,
+        path: ["osVersion"],
+      });
     }
   };
 }
@@ -860,20 +887,6 @@ export const workerUpdate = defineOperation({
 
 // ---- component.install (ADR 0010 §6) --------------------------------------------------------
 
-/**
- * A component's version as the catalog lists it under `runtimes` (`26.4`, `35`), carried to the
- * driver unread -- which is why its shape is bounded here, before it reaches one (safety rule
- * 10): a driver builds an installer argument from it. One to 64 characters, none of them
- * whitespace or a control character, and not starting with `-`, which an installer could read
- * as an option.
- */
-const componentVersionSchema = z
-  .string()
-  .min(1)
-  .max(64)
-  .regex(/^[^\s\p{Cc}]+$/u, "must contain no whitespace or control character")
-  .refine((version) => !version.startsWith("-"), "must not start with '-'");
-
 /**
  * Installs one iOS simulator runtime or Android system image without leasing a device (ADR 0010
  * §6). Admin-only: the command is an operator's consent to a multi-GB download, which
diff --git a/src/daemon/AGENTS.md b/src/daemon/AGENTS.md
index f7693da0..0b300c07 100644
--- a/src/daemon/AGENTS.md
+++ b/src/daemon/AGENTS.md
@@ -59,7 +59,7 @@ Its stdout lines move the state; a failed line, a non-zero exit or a failed laun
 2. **Hello** — first frame must be `hello`, else `HANDSHAKE_REQUIRED` and close.
    Role: the uplink connection is `admin` by acceptance; otherwise the resolver. Principal: `hello.principal`, else `SIMLOCK_AGENT_ID`, else the daemon's pid. Both are fixed for the connection's life.
 3. **Version** — ranges overlap → highest common version. `PROTOCOL_VERSION_RANGE`
-   is `{ min: 59, max: 59 }` (`src/contract/protocol.ts`). No overlap → the
+   is `{ min: 62, max: 62 }` (`src/contract/protocol.ts`). No overlap → the
    connection stays open, and every request but `daemon.stop` gets
    `PROTOCOL_VERSION_UNSUPPORTED`.
 4. **Request** — one frame → one `dispatch()` call. While stopping: `DAEMON_STOPPING`.
diff --git a/src/daemon/server.test.ts b/src/daemon/server.test.ts
index f11232f5..928f19fa 100644
--- a/src/daemon/server.test.ts
+++ b/src/daemon/server.test.ts
@@ -2410,7 +2410,16 @@ describe("DaemonServer download policy", () => {
 
   it("still answers a lease request whose download names a component past the progress push's bound, sending no downloading push for it and logging that", async () => {
     const clock = new FakeClock(1_000);
-    const driver = new FakeDriver({ availableOsVersions: [], clock, platform: "ios" });
+    const driver = new FakeDriver({ availableOsVersions: ["26.5"], clock, platform: "ios" });
+    // why: the driver, not the request, names the component: a request's exact osVersion is held
+    // within the push's bound. Every resolve before the install answers as a missing runtime does.
+    for (const callNumber of [1, 2]) {
+      driver.failOn(
+        "resolveSpec",
+        callNumber,
+        new RuntimeMissingError("ios", "26.5", { component: "9".repeat(65) }),
+      );
+    }
     const sink = new MemoryLogSink();
     const harness = await createHarness({
       clock,
@@ -2419,13 +2428,12 @@ describe("DaemonServer download policy", () => {
     });
     const client = await createClient(harness.socketPath);
     await hello(client);
-    const osVersion = "9".repeat(65);
 
     const grant = await client.request("lease.request", {
       allowDownload: true,
       requesterId: "agent-1",
       model: "iPhone 16",
-      osVersion,
+      osVersion: "26.5",
       platform: "ios",
     });
 
diff --git a/website/src/content/docs/docs/using-devices/choosing-a-device.mdx b/website/src/content/docs/docs/using-devices/choosing-a-device.mdx
index 24f76e5d..571539ec 100644
--- a/website/src/content/docs/docs/using-devices/choosing-a-device.mdx
+++ b/website/src/content/docs/docs/using-devices/choosing-a-device.mdx
@@ -73,7 +73,7 @@ Without `--os`, the lease gets the newest runtime installed for that platform. U
 
 A range is one or more of `>=`, `>`, `<=`, `<` followed by a version, separated by single spaces, or a hyphen range with spaces around the hyphen. A short version covers everything under it, so `<=26` includes 26.1. Quote ranges so the shell does not read `>` or `<`.
 
-Forms like `^18`, `~18`, `18.x`, `*` and `||` are refused with `BAD_REQUEST` (exit 2). Any other text is an exact version, which is how Android names such as `Baklava` or `34-ext12` work.
+Forms like `^18`, `~18`, `18.x`, `*` and `||` are refused with `BAD_REQUEST` (exit 2). Any other text is an exact version, which is how Android names such as `Baklava` or `34-ext12` work. An exact version is 1 to 64 characters with no spaces, control characters or `;`, and does not start with `-`; anything else is refused with `BAD_REQUEST`.
 
 A range takes an idle device whose OS is inside it first, and otherwise creates a device on the newest installed runtime inside it. A range never downloads anything: if no installed runtime is inside it, the lease fails at once with `RUNTIME_MISSING` (exit 12).