Claude Code 2.1.296 raises the MCP instructions cap to 4,096
Claude Code 2.1.296 doubled the default MCP instructions cap to 4,096 characters. Sume's server instructions are about 10,900, so the cap still applies.
Claude Code 2.1.296 (Oct 9, 2026) raised the default limit on MCP server instructions, and on MCP tool descriptions sent up front, from 2,048 to 4,096 characters. Sume's hosted server still sends instructions longer than that (about 10,900 characters in the current source), so Claude Code cuts them off; the contract you rely on lives in tools_list and tools_schema, not in the instructions text.
What changed, with dates
Both Claude Code rows below come from the Claude Code changelog, which we read on 2026-10-10. The Sume figure further down is a measurement of the instruction string in our repository, not a vendor claim.
| Item | Before 2.1.296 | 2.1.296 (Oct 9) | 2.1.295 (Oct 8) |
|---|---|---|---|
| MCP tool descriptions sent up front | 2,048 characters | 4,096 characters | unchanged |
| MCP server instructions | 2,048 characters | 4,096 characters | unchanged |
| Tool descriptions loaded through tool search | 2,048 characters | unchanged | cut at 16,384 characters |
Where Sume lands
Sume's remote server returns routing prose in the instructions field of initialize: social discovery, generation routing, web research, the spend and idempotency contract and a refusal list. Concatenated, that string measures roughly 10,900 characters in packages/mcp-server/src/mcp-instructions.ts on main today (10,281 when social scrape lives on a separate Social server). Either way it is more than double the new 4,096 cap.
So the new default helps clients that print instructions, but it does not make the whole string visible. Treat the first 4,096 characters as what a default Claude Code session sees, and treat everything else as unseen.
What to do about it
Nothing in the safety model depends on the instructions being read. The gates are enforced by the server and documented on the MCP tools and gates page:
- Paid and write tools need an
idempotency_key, whatever the model read or skipped. dry_run=truepreviews cost without submitting;max_spend_usdis enforced only when you send it.- Under OAuth
mcp:readthe write and paid tools are hidden, and calls returninsufficient_scope. - Call
tools_schemawith a toolnameto read one contract on demand instead of trusting truncated prose.
Check it in your own session
Connect as in the MCP quickstart (claude mcp add --transport http sume https://mcp.sume.com/mcp), then open the context view to see how much of the instructions row survives. If your workflow needs routing hints that sit past character 4,096, put them in your own CLAUDE.md or a project skill rather than expecting the server text to arrive whole.
Upgrading from 2.1.295 changes no Sume setting. It is a client display and budget change, and no re-login is needed.
Sources
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