Document available hosted agent sizes

[gukoff]

Hosted agents seem to require specific replica sizes. Attempting to create any other agent sizes results in a validation error.

By the way, the definition.memory error message gives wrong memory limits. Could you fix it internally in the product?

---

Validation error:

{
   "error": {
      "code": "invalid_payload",
      "message": "Invalid payload",
      "param": null,
      "type": "invalid_request_error",
      "details": [
         {
         "code": "ValidationError",
         "message": "CPU must be a decimal number representing cores. Examples: '0.25', '0.5', '1', '2', '3.5'",
         "param": "definition.cpu",
         "type": "error"
         },
         {
         "code": "ValidationError",
         "message": "CPU must be between 0.25 and 3.5 cores.",
         "param": "definition.cpu",
         "type": "error"
         },
         {
         "code": "ValidationError",
         "message": "CPU must be in increments of 0.25. Valid values: 0.25, 0.5, 0.75, 1, 1.25, etc.",
         "param": "definition.cpu",
         "type": "error"
         },
         {
         "code": "ValidationError",
         "message": "The specified condition was not met for 'Cpu'.",
         "param": "definition.cpu",
         "type": "error"
         },
         {
         "code": "ValidationError",
         "message": "Memory must be specified in GiB format only. Examples: '0.5Gi', '1Gi', '1.5Gi', '4Gi', '7Gi'",
         "param": "definition.memory",
         "type": "error"
         },
         {
         "code": "ValidationError",
         "message": "Memory must be between 1 Gi and 7 Gi.",
         "param": "definition.memory",
         "type": "error"
         },
         {
         "code": "ValidationError",
         "message": "Memory must be in increments of 0.5Gi. Valid values: 0.5Gi, 1Gi, 1.5Gi, 2Gi, 2.5Gi, etc.",
         "param": "definition.memory",
         "type": "error"
         },
         {
         "code": "ValidationError",
         "message": "CPU and Memory must be specified as a valid combination. Valid pairs: (0.25, 0.5Gi), (0.5, 1Gi), (0.75, 1.5Gi), (1, 2Gi), (1.25, 2.5Gi), (1.5, 3Gi), (1.75, 3.5Gi), (2, 4Gi), (2.25, 4.5Gi), (2.5, 5Gi), (2.75, 5.5Gi), (3, 6Gi), (3.25, 6.5Gi), (3.5, 7Gi)",
         "param": "definition",
         "type": "error"
         }
      ],
      "additionalInfo": {
         "request_id": "e598b1a8c1bf324767fa26236c69333a"
      }
   }
}

[prmerger-automator]

@gukoff : Thanks for your contribution! The author(s) and reviewer(s) have been notified to review your proposed change.

[learn-build-service-prod]

Learn Build status updates of commit 16e381a:

✅ Validation status: passed

File	Status	Preview URL	Details
articles/ai-foundry/default/agents/concepts/hosted-agents.md	✅Succeeded

For more details, please refer to the build report.

[ttorble]

@aahill

Can you review the proposed changes?

IMPORTANT: When the changes are ready for publication, adding a #sign-off comment is the best way to signal that the PR is ready for the review team to merge.

#label:"aq-pr-triaged"
@MicrosoftDocs/public-repo-pr-review-team

[Copilot]

Pull request overview

This PR adds documentation for the supported CPU and memory size configurations for hosted agents in Microsoft Foundry Agent Service. The change addresses a gap in the documentation by providing developers with a clear reference table of valid replica sizes, which helps prevent validation errors when creating hosted agents.

Key Changes

• Adds a new "Agent sizes" subsection under "Understand key concepts" with a comprehensive table listing all 14 supported CPU/memory pairs
• Clarifies that these values define replica sizes and that agents can run multiple replicas

[Copilot]

The heading "Agent sizes" should be changed to "Agent replica sizes" to more accurately reflect that these values define the size of each replica, not the agent as a whole. The current heading could be misleading since the following text clarifies that "an agent can run multiple replicas." Using "Agent replica sizes" makes the scope clearer immediately.

Suggested change

	### Agent sizes
	### Agent replica sizes