Skip to content

[Doc] Clarify server_context Hash requirement for _meta merging #372

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
koic wants to merge 1 commit into
base: main
Choose a base branch
from
+5 −0
Open

[Doc] Clarify server_context Hash requirement for _meta merging #372

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -260,6 +260,11 @@ See the relevant sections below for the arguments they receive.

The MCP protocol supports a special [`_meta` parameter](https://modelcontextprotocol.io/specification/2025-06-18/basic#general-fields) in requests that allows clients to pass request-specific metadata. The server automatically extracts this parameter and makes it available to tools and prompts as a nested field within the `server_context`.

> [!NOTE]
> `_meta` is only merged when `server_context` is a `Hash` (or `nil`, in which case a new `{ _meta: ... }` hash is synthesized).
> If you assign a non-`Hash` value to `server_context`, `_meta` is not merged and tools will not see it
> under `server_context[:_meta]`. Keep `server_context` as a `Hash` if your tools need access to `_meta`.

**Access Pattern:**

When a client includes `_meta` in the request params, it becomes available as `server_context[:_meta]`:
Expand Down