MCP SDK 2.x read-only hint attribute casing bug
Cluster 109817. Data as of
Nothing open on GitHub. Fix merged in #133532 on 5 Oct 2026. Check it covers your case.
The short answer
- Known?
- Yes. 3 related items grouped here, 1 issue already closed.
- Fix event
- A fix was merged to main in PR #133532. Check it covers your case. No release data is tracked.
- Tracker
- The maintainers' tracker marks this
unresolved. That is separate from the fix event. - Still open
- Nothing open on GitHub.
These items concern a bug where the MCP trust gate fails to detect read-only tool hints in SDK 2.x due to a camelCase vs. snake_case attribute naming mismatch. A fix to support the snake_case read_only_hint attribute is included.
Open issues0
Open PRs0
Fixes on record
-
#133532 MCP read-only tools on untrusted servers stop asking for approval under mcp 2.x (salvage #111270)
files:
contributors/emails/[redacted:email],tests/e2e/core/mcp_plugins/test_mcp_stdio_conformance.py,tests/tools/test_mcp_trust_gating.py,tools/mcp_tool_registration.py
1 PR closed without merging
From the close comments: done elsewhere 1
-
#111618 fix(tools): support snake_case read_only_hint in MCP SDK 2.x · done elsewhere →
4b6884a,#133532,#111270,#88372
Closed issues · 1
- Closed#109817MCP trust gate never sees readOnlyHint on mcp SDK 2.x: `_annotation_read_only_hint` reads the camelCase attribute
How this cluster was grouped
-
Link evidence (
structural links throughout): every member is connected by structural evidence: shared changed files, or a closing/superseded reference. -
Pairwise link density
0.67: the share of item pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36.1.00means every pair is linked.
Pick up a Lab task
Check whether a fix covers the open issues here, with your own agent. Bring back evidence for maintainers.
Open the LabAt a glance
- Merged PRs
- #133532
- Closed issues
- 1
- Attempts
- 1 PR closed without merging
- Fix link checked
- 5 Oct 2026