feat(tasks)!: reject a taskDefaultTtlMs above taskMaxTtlMs

README.md

@@ -382,10 +382,10 @@ A client-requested `ttl` must be a non-negative integer number of milliseconds;
 `CreateTaskResult`.
 
 `taskDefaultTtlMs`, `taskMaxTtlMs` and `taskLeaseMs` must be positive integer numbers of
-milliseconds and `taskMaxRetainedPerPrincipal` a positive integer. Registration throws a
-`TypeError` naming the option otherwise, so a typo or a value read from an environment variable
-as a string fails at startup rather than failing every task. A `taskDefaultTtlMs` above
-`taskMaxTtlMs` is capped to it.
+milliseconds, `taskMaxRetainedPerPrincipal` a positive integer, and `taskDefaultTtlMs` must not
+exceed `taskMaxTtlMs` (default 1 hour). Registration throws a `TypeError` naming the option
+otherwise, so a typo or a value read from an environment variable as a string fails at startup
+rather than failing every task.
 
 Tasks are stored in memory by default and in Redis when a `redis` option is given, so any
 instance can serve a poll for a task created on another.

src/handlers.ts

@@ -923,7 +923,7 @@ const DEFAULT_POLL_INTERVAL = 1000
 const DEFAULT_TASK_TTL = 60_000
 
 /** Ceiling on retention, so a client cannot pin resources indefinitely */
-const MAX_TASK_TTL = 3600_000
+export const MAX_TASK_TTL = 3600_000
 
 /**
  * Floor on retention. A smaller ttl (0 included) would let the task expire

src/index.ts

@@ -22,6 +22,7 @@ import oauthClientPlugin from './auth/oauth-client.ts'
 import authRoutesPlugin from './routes/auth-routes.ts'
 import { quitWithTimeout } from './redis-quit-with-timeout.ts'
 import { createJsonSchemaValidator } from './validation/json-schema-validator.ts'
+import { MAX_TASK_TTL } from './handlers.ts'
 import {
   createMcpClient,
   type McpClient,
@@ -110,6 +111,11 @@ const mcpPlugin = fp(async function (app: FastifyInstance, opts: MCPPluginOption
       throw new TypeError(`${name} must be a positive integer number of milliseconds, got ${String(value)}`)
     }
   }
+  // An unset default is capped by the ceiling, but an explicit one above it is a mistake
+  const taskMaxTtlMs = opts.taskMaxTtlMs ?? MAX_TASK_TTL
+  if (opts.taskDefaultTtlMs !== undefined && opts.taskDefaultTtlMs > taskMaxTtlMs) {
+    throw new TypeError(`taskDefaultTtlMs (${opts.taskDefaultTtlMs}) must not exceed taskMaxTtlMs (${taskMaxTtlMs})`)
+  }
   const tools = new Map<string, MCPTool>()
   const resources = new Map<string, MCPResource>()
   const prompts = new Map<string, MCPPrompt>()

test/task-options-validation.test.ts

@@ -61,9 +61,12 @@ describe('task options validation (#302)', () => {
     await assertRegistrationAccepts(t, { taskMaxRetainedPerPrincipal: 20 })
   })
 
-  test('registration accepts a taskDefaultTtlMs above taskMaxTtlMs, which is capped', async (t: TestContext) => {
-    await assertRegistrationAccepts(t, { taskDefaultTtlMs: 120_000, taskMaxTtlMs: 60_000 })
-    await assertRegistrationAccepts(t, { taskDefaultTtlMs: 2 * 3600_000 })
+  test('registration throws when taskDefaultTtlMs exceeds taskMaxTtlMs', async (t: TestContext) => {
+    await assertRegistrationRejects(t, { taskDefaultTtlMs: 120_000, taskMaxTtlMs: 60_000 }, /taskDefaultTtlMs \(120000\) must not exceed taskMaxTtlMs \(60000\)/)
+  })
+
+  test('registration throws when taskDefaultTtlMs exceeds the default taskMaxTtlMs', async (t: TestContext) => {
+    await assertRegistrationRejects(t, { taskDefaultTtlMs: 2 * 3600_000 }, /taskDefaultTtlMs \(7200000\) must not exceed taskMaxTtlMs \(3600000\)/)
   })
 
   test('registration accepts taskDefaultTtlMs equal to taskMaxTtlMs', async (t: TestContext) => {