akashjainn
f99cdb649b
mcp: base64-encode a non-header-safe Mcp-Name ( #1246 ) ...
Fixes: https://github.com/modelcontextprotocol/go-sdk/issues/1243
The 2026-07-28 transport spec only SHOULD-constrains names to
header-safe characters, and lets a client Base64-wrap one that is not,
using the `=?base64?...?=` sentinel. `setStandardHeaders` set `Mcp-Name`
raw, while the sibling `Mcp-Param-*` path already ran its values through
`encodeHeaderValue`, so a name outside the safe set went out unencoded.
This routes `Mcp-Name` through `encodeHeaderValue` as well.
#1242 landed the other direction — the server decoding the sentinel
before comparing — so the two together close the round trip. Worth
noting they interact: after #1242 , a name that is literally shaped like
the sentinel (`=?base64?abc?=`) is now rejected as invalid Base64,
because the server tries to decode a value the client never encoded. The
new test covers that case, and it fails on `main` today.
`extractName` also covers `resources/read`, so this applies to resource
URIs, which is where non-ASCII is most likely to show up in practice.
## Testing
`TestMcpNameHeaderEncodingRoundTrip` drives `setStandardHeaders` and
then feeds its output to `validateMcpHeaders`, so it pins the client and
server halves against each other rather than asserting the encoding in
isolation. Cases: an ASCII-safe name (must stay unencoded, no churn for
the common path), non-ASCII, a leading space, a control character, and
the sentinel-shaped literal above.
Verified failing before the change and passing after. `go test ./...`
passes.
A note on process:
[@remote-controlled-man](https://github.com/remote-controlled-man ) asked
about this issue earlier today and proposed much the same scope. I had
the change written before I saw that comment and thought the #1242
interaction was worth surfacing either way, but I'm happy to close this
if they'd rather carry it — please just say so.
🤖 Generated with [Claude Code](https://claude.com/claude-code )
https://claude.ai/code/session_011Wf643Lx36V5wdwuuf2EdT
2026-09-07 10:16:16 +02:00
mcp: update return meta in DiscoverResult (SEP-2575) ( #1097 )
2026-07-16 16:10:12 +02:00
mcp: do not enforce TTL on cached tool ( #1053 )
2026-07-07 13:43:10 +02:00
mcp: add 2026-07-28 to the supported protocol versions ( #1020 )
2026-06-24 12:02:56 +02:00
fix: only subscribe when server advertises capability ( #1221 )
2026-09-01 14:43:23 +02:00
mcp: add docs for tier 1 assessment ( #1195 )
2026-08-24 12:00:59 +02:00
mcp: allow any value for schemas ( #517 )
2025-09-26 11:55:54 -04:00
mcp: export ClientSessionOptions.ProtocolVersion ( #1127 )
2026-08-03 15:29:52 +02:00
mcp: speed up TestCommandTransportDuration
2025-09-12 12:00:29 -04:00
mcp: speed up TestCommandTransportDuration
2025-09-12 12:00:29 -04:00
all: modernize code ( #868 )
2026-03-31 10:58:02 +02:00
mcp: add 2026-07-28 to the supported protocol versions ( #1020 )
2026-06-24 12:02:56 +02:00
mcp: Deprecate roots, sampling and logging (SEP-2577) ( #1017 )
2026-06-23 11:11:08 +02:00
mcp: update return meta in DiscoverResult (SEP-2575) ( #1097 )
2026-07-16 16:10:12 +02:00
mcp: switch icon theme to named string type ( #733 )
2025-12-19 16:44:10 -05:00
mcp: add ServerSession.NotifyElicitationComplete ( #1194 )
2026-08-24 10:14:28 +02:00
mcp: add ServerSession.NotifyElicitationComplete ( #1194 )
2026-08-24 10:14:28 +02:00
mcp: add an sse event size cap ( #1205 )
2026-09-02 11:35:23 +02:00
mcp: add an sse event size cap ( #1205 )
2026-09-02 11:35:23 +02:00
mcp: minor cleanup of some TODOs ( #332 )
2025-08-20 12:55:19 -04:00
mcp: change tool handler design ( #325 )
2025-08-20 19:36:34 -04:00
mcp: keep request log levels scoped to each request ( #1168 )
2026-08-17 14:00:41 +02:00
mcp: fix inaccurate package doc ( #534 )
2025-09-26 14:16:10 -04:00
mcp: add 2026-07-28 to the supported protocol versions ( #1020 )
2026-06-24 12:02:56 +02:00
fix: only subscribe when server advertises capability ( #1221 )
2026-09-01 14:43:23 +02:00
mcp: don't mutate caller params on multi-round-trip retries ( #1145 )
2026-08-31 13:53:34 +02:00
mcp: don't mutate caller params on multi-round-trip retries ( #1145 )
2026-08-31 13:53:34 +02:00
mcp: align PromptHandler args with other handlers ( #348 )
2025-08-22 10:44:05 -04:00
refactor: remove legacy MCPGODEBUG compatibility for new protocol release ( #1237 )
2026-09-04 10:08:52 +02:00
mcp: include resultType on new-protocol responses ( #1060 )
2026-07-13 11:51:19 +00:00
mcp: Implement subscriptions/listen rpc (SEP-2575) ( #1007 )
2026-06-22 18:57:36 +02:00
mcp: align resource not found error code with sep-2164 ( #931 )
2026-05-05 16:20:02 +02:00
mcp/Resource: Refactor URI Template Matching with uritemplate Library ( #100 )
2025-07-08 15:52:54 -04:00
mcp: export ClientSessionOptions.ProtocolVersion ( #1127 )
2026-08-03 15:29:52 +02:00
perf: add schema caching to avoid repeated reflection ( #685 )
2026-01-20 20:16:46 -05:00
all: modernize code ( #868 )
2026-03-31 10:58:02 +02:00
mcp: allow per request Cacheable customization ( #1203 )
2026-09-01 18:57:51 +00:00
mcp: add docs for tier 1 assessment ( #1195 )
2026-08-24 12:00:59 +02:00
mcp: allow per request Cacheable customization ( #1203 )
2026-09-01 18:57:51 +00:00
mcp: allow restricting the protocol versions a server supports ( #1199 )
2026-08-28 16:06:10 +02:00
mcp: do not check metatada on notifications ( #1215 )
2026-09-01 13:30:20 +00:00
mcp: update return meta in DiscoverResult (SEP-2575) ( #1097 )
2026-07-16 16:10:12 +02:00
refactor: remove legacy MCPGODEBUG compatibility for new protocol release ( #1237 )
2026-09-04 10:08:52 +02:00
mcp: add docs for tier 1 assessment ( #1195 )
2026-08-24 12:00:59 +02:00
mcp: add a max request body size of the old transport ( #1224 )
2026-09-01 17:28:35 +02:00
refactor: remove legacy MCPGODEBUG compatibility for new protocol release ( #1237 )
2026-09-04 10:08:52 +02:00
all: modernize code ( #868 )
2026-03-31 10:58:02 +02:00
mcp: do not call DELETE for sessionless & doc adjustments ( #960 )
2026-05-15 21:47:34 +02:00
mcp: tolerate 404 on subscriptions/listen in stateless mode ( #1193 )
2026-08-25 14:27:37 +02:00
mcp: add 2026-07-28 to the supported protocol versions ( #1020 )
2026-06-24 12:02:56 +02:00
mcp: base64-encode a non-header-safe Mcp-Name ( #1246 )
2026-09-07 10:16:16 +02:00
mcp: base64-encode a non-header-safe Mcp-Name ( #1246 )
2026-09-07 10:16:16 +02:00
mcp: simplify stream state management in streamable transport
2025-12-10 13:28:25 -05:00
mcp: add an sse event size cap ( #1205 )
2026-09-02 11:35:23 +02:00
mcp: add docs for tier 1 assessment ( #1195 )
2026-08-24 12:00:59 +02:00
mcp: add docs for tier 1 assessment ( #1195 )
2026-08-24 12:00:59 +02:00
mcp: tool.InputSchema and tool.OutputSchema validation (SEP-2106) ( #1009 )
2026-06-16 13:55:47 +02:00
mcp: add an sse event size cap ( #1205 )
2026-09-02 11:35:23 +02:00
mcp: update return meta in DiscoverResult (SEP-2575) ( #1097 )
2026-07-16 16:10:12 +02:00
mcp: add an sse event size cap ( #1205 )
2026-09-02 11:35:23 +02:00
all: use case-sensitive JSON unmarshaling ( #807 )
2026-02-18 16:38:36 +01:00
f99cdb649b