MCP TypeScript SDK 2.3 maxToolInputElements: Sume tool arguments
MCP TypeScript SDK 2.3.0 adds maxToolInputElements on McpServer. A server-side cap on array size; here is how it relates to Sume's tool arguments.
maxToolInputElements is a server-side option, so it limits what a server will accept, not what a client may send to Sume. MCP TypeScript SDK v2.3.0 (2026-10-02) adds it to McpServer, and Sume's hosted server is not built from your SDK version, so your client code is unaffected.
It is still useful to know if you write your own MCP server beside Sume's.
What the option is
The v2.3.0 release notes list maxToolInputElements on McpServer as a guard on tool input size. They also add expectedResource on bearer validation, same-origin-only redirects unless redirectPolicy is set to follow, and tasks/get and tasks/cancel in the Tasks extension.
At a glance
| Limit | Where it applies | Value |
|---|---|---|
| maxToolInputElements | McpServer in the TypeScript SDK | Configurable |
| jobs_wait ids | Sume tool input | 20 |
| Tool output size | Sume tool result | 256 KiB |
Sume's own limits
Sume documents limits per tool in the schema it returns: call tools_schema to read the input constraints, such as the 20-id cap on jobs_wait. Results larger than 256 KiB come back as an error with code mcp_output_too_large, which is an output limit and not a job failure.
If you build a custom server, set maxToolInputElements and document it the way Sume documents its caps.
- Read limits from tools_schema, not from guesses.
- Never resubmit a paid create after an output-limit error.
- A server cap is not a client cap.
Limits and what is not verified
I did not find a public statement of the default for maxToolInputElements, so no default is given here. This post does not claim anything about array limits on Sume tools beyond jobs_wait.
Sources
Related posts
More in Developers
- MAI-Transcribe-2-Streaming '2x faster': measure your caption delay
Microsoft says words appear 2x faster than its closest competitor. Measure your own delay from speech to caption with a p50 and p95 script before you switch.
- Microsoft Agent Framework hosted MCP tool for Sume (Python)
Attach https://mcp.sume.com/mcp to an Agent Framework agent with get_mcp_tool, allowed_tools and approval_mode. Foundry runs the calls, so mind the key.
- Migrate Video 1.0 to sume/auto on POST /v1/videos, field by field
Video 1.0 is retiring soon. Which fields move, which are ignored or rejected, and the request to send on POST /v1/videos with sume/auto.
- Migrate POST /v1/video-router/generate to /v1/videos: a field map
Same model ids, same jobs, different wire. How image_url and reference_image_urls become frame_images and input_references, and what stays on Video Router.
Written by Sume