More strictly enforce Accept MCP

DEPENDENCIES

@@ -1,6 +1,6 @@
 vendorpull https://github.com/sourcemeta/vendorpull 1dcbac42809cf87cb5b045106b863e17ad84ba02
 uwebsockets https://github.com/uNetworking/uWebSockets v20.78.0
-core https://github.com/sourcemeta/core d50aab1249c1e6c38977d859557ce84342aa1d7d
+core https://github.com/sourcemeta/core 44ccfc458f8fd66870635c0d4c49d4814097277e
 blaze https://github.com/sourcemeta/blaze 3c2ddb90f26eb50821442f54c5db88276ab9a558
 bootstrap https://github.com/twbs/bootstrap v5.3.3
 bootstrap-icons https://github.com/twbs/icons v1.11.3

enterprise/e2e/html/hurl/mcp-2025-03-26-batch.all.hurl

@@ -2,6 +2,7 @@
 # batch case to fully assert the inner template descriptor without duplicating
 # the canonical resourceTemplates assertion across hurl files
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -20,6 +21,7 @@ jsonpath "$.result.resourceTemplates[0].uriTemplate" == "{{base}}/{+path}{?bundl
 # return responses as an array in any order. We preserve input order so clients
 # do not have to id-match
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -72,6 +74,7 @@ jsonpath "$.valid" == true
 # valid one dispatches normally. The invalid one returns its own Invalid
 # Request envelope. Neither failure can poison the other
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -123,6 +126,7 @@ jsonpath "$.valid" == true
 # empty array, it must "return nothing at all". We use the same 202 Accepted
 # semantics the single-notification path uses
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -144,6 +148,7 @@ bytes count == 0
 # Empty array body. JSON-RPC §6 explicitly says this must produce a single
 # Response object, not an empty array
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -187,6 +192,7 @@ jsonpath "$.valid" == true
 # the shape of the request. Batch-aware clients distinguish "single response"
 # from "1-element array"
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -229,6 +235,7 @@ jsonpath "$.valid" == true
 # response entry, but the body is still a 1-element array because at least
 # one response exists
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -278,6 +285,7 @@ jsonpath "$.valid" == true
 # below still validates the whole batch body against the wrapped
 # `mcp/response` schema, which keeps the contract on the response shape
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -332,6 +340,7 @@ jsonpath "$.valid" == true
 # Batch where a tool call references an unknown tool. The error envelope is
 # returned for that sub-element while the rest of the batch proceeds
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -382,6 +391,7 @@ jsonpath "$.valid" == true
 # Batch elements with identical ids. The spec does not forbid id collisions,
 # clients are responsible for picking unique ones. We must still process both
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -432,6 +442,7 @@ jsonpath "$.valid" == true
 # yields its own Invalid Request envelope. The response array has one entry
 # per sub-element (id null because non-objects have no id to echo)
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -485,6 +496,7 @@ jsonpath "$.valid" == true
 
 # Batch on 2025-06-18 is rejected with a single Invalid Request envelope
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -526,6 +538,7 @@ jsonpath "$.valid" == true
 
 # Same single-envelope rejection on 2025-11-25
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-11-25
 Content-Type: application/json
 ```
@@ -569,6 +582,7 @@ jsonpath "$.valid" == true
 # version. The wrong-version one comes back as Invalid Request, the other
 # dispatches normally
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```

enterprise/e2e/html/hurl/mcp-2025-03-26.all.hurl

@@ -1,4 +1,5 @@
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -59,6 +60,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -105,6 +107,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -153,6 +156,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -197,6 +201,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -328,6 +333,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -382,6 +388,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -456,6 +463,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```
@@ -531,6 +539,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-03-26
 Content-Type: application/json
 ```

enterprise/e2e/html/hurl/mcp-2025-06-18-batch.all.hurl

@@ -5,6 +5,7 @@
 
 # Single-element batch
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -46,6 +47,7 @@ jsonpath "$.valid" == true
 
 # Multi-element batch with otherwise-valid requests
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -90,6 +92,7 @@ jsonpath "$.valid" == true
 
 # Empty array body
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -133,6 +136,7 @@ jsonpath "$.valid" == true
 # 2025-06-18 the version rejects the batch wrapper itself, so the contents
 # do not matter and the response is still the Invalid Request envelope
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -177,6 +181,7 @@ jsonpath "$.valid" == true
 
 # Batch with garbage sub-elements
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```

enterprise/e2e/html/hurl/mcp-2025-06-18.all.hurl

@@ -1,4 +1,5 @@
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -56,6 +57,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -99,6 +101,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -144,6 +147,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -188,6 +192,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -241,6 +246,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -289,6 +295,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```
@@ -383,6 +390,7 @@ header "Date" matches /^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0[1-9]|[12][0-9]|3[01])
 jsonpath "$.valid" == true
 
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-06-18
 Content-Type: application/json
 ```

enterprise/e2e/html/hurl/mcp-2025-11-25-batch.all.hurl

@@ -5,6 +5,7 @@
 
 # Single-element batch
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-11-25
 Content-Type: application/json
 ```
@@ -46,6 +47,7 @@ jsonpath "$.valid" == true
 
 # Multi-element batch with otherwise-valid requests
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-11-25
 Content-Type: application/json
 ```
@@ -90,6 +92,7 @@ jsonpath "$.valid" == true
 
 # Empty array body
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-11-25
 Content-Type: application/json
 ```
@@ -133,6 +136,7 @@ jsonpath "$.valid" == true
 # 2025-06-18 the version rejects the batch wrapper itself, so the contents
 # do not matter and the response is still the Invalid Request envelope
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-11-25
 Content-Type: application/json
 ```
@@ -177,6 +181,7 @@ jsonpath "$.valid" == true
 
 # Batch with garbage sub-elements
 POST {{base}}/self/v1/mcp
+Accept: application/json, text/event-stream
 MCP-Protocol-Version: 2025-11-25
 Content-Type: application/json
 ```