Documentation Index
Fetch the complete documentation index at: https://modelcontextprotocol.io/llms.txt
Use this file to discover all available pages before exploring further.
The Model Context Protocol uses string-based version identifiers following the format
YYYY-MM-DD, to indicate the last date backwards incompatible changes were made.
The protocol version will not be incremented when the
protocol is updated, as long as the changes maintain backwards compatibility. This allows
for incremental improvements while preserving interoperability.
Revisions
Revisions may be marked as:
- Draft: in-progress specifications, not yet ready for consumption.
- Current: the current protocol version, which is ready for use and may continue to
receive backwards compatible changes.
- Final: past, complete specifications that will not be changed.
The current protocol version is 2025-11-25.
Feature States
Individual features of the specification may additionally be marked as
Deprecated under the
feature lifecycle and deprecation policy:
the feature remains part of the specification, but is scheduled for removal.
Deprecated features document a migration path (or state that none is required)
and remain in the specification for at least twelve months, or at least
ninety days under the policy’s
expedited-removal exception,
before they become eligible for removal, after which they may be Removed
in a future revision.
Features that are currently Deprecated are listed in the
deprecated features registry.
Negotiation
Version negotiation happens during
initialization. Clients and
servers MAY support multiple protocol versions simultaneously, but they MUST
agree on a single version to use for the session.
The protocol provides appropriate error handling if version negotiation fails, allowing
clients to gracefully terminate connections when they cannot find a version compatible
with the server.
