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jfallowsclaude
jfallows
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claude
authored
Add test for elicitation challenge after tool result (#1842)
* fix(binding-mcp): fail loud on elicitation challenge after JSON result When an mcp server is composed in front of an arbitrary mcp-speaking binding, the reply-side frame arrival order is not guaranteed. Once the POST response has committed to application/json, a subsequent elicitation CHALLENGE (which requires text/event-stream) is an illegal logical-state transition that cannot be honored — the content-type is already on the wire and cannot be upgraded. Detect this in McpRequestStream.onAppChallenge via the existing state (replyOpening(server.state) && !sseUpgrade) and tear the request down (app RESET + net ABORT) instead of emitting a malformed SSE event into a JSON response. The FLUSH-after-commit case already failed loud. Adds the tools.call.elicit.after.result scenario with McpServerIT, NetworkIT and ApplicationIT coverage. * test(binding-mcp): use server.timeout.yaml for shouldCallToolElicitCompleted shouldCallToolElicitCompleted exercises the URL-elicitation hold-and-resume flow, which requires options.timeout > 0. The test was annotated @configuration("server.yaml") (which has no timeout option), so session.requestTimeout resolved to 0 and the elicitation was rejected with -32042 URLElicitationRequiredError instead of streaming over text/event-stream — failing the test (and turning develop CI red on this test). Restore @configuration("server.timeout.yaml") so the elicitation hold path is exercised as intended. --------- Co-authored-by: Claude <noreply@anthropic.com>
1 parent 837336b commit e1ccefe

8 files changed

Lines changed: 441 additions & 2 deletions

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‎runtime/binding-mcp/src/main/java/io/aklivity/zilla/runtime/binding/mcp/internal/stream/McpServerFactory.java‎

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4570,7 +4570,11 @@ private void onAppChallenge(
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challengeEx = mcpChallengeExRO.tryWrap(extension.buffer(), extension.offset(), extension.limit());
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}
45724572

4573-
if (challengeEx != null && challengeEx.kind() == McpChallengeExFW.KIND_ELICIT_CREATE)
4573+
if (sse == null && McpState.replyOpening(server.state) && !server.sseUpgrade)
4574+
{
4575+
cleanupApp(traceId, authorization);
4576+
}
4577+
else if (challengeEx != null && challengeEx.kind() == McpChallengeExFW.KIND_ELICIT_CREATE)
45744578
{
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onAppChallengeElicitCreate(traceId, authorization, challengeEx.elicitCreate());
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}

‎runtime/binding-mcp/src/test/java/io/aklivity/zilla/runtime/binding/mcp/internal/stream/McpServerIT.java‎

Lines changed: 11 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -315,7 +315,7 @@ public void shouldCallToolWithUpstreamResumableFlush() throws Exception
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}
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@Test
318-
@Configuration("server.yaml")
318+
@Configuration("server.timeout.yaml")
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@Specification({
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"${net}/tools.call.elicit.completed/client",
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"${app}/tools.call.elicit.completed/server"})
@@ -324,6 +324,16 @@ public void shouldCallToolElicitCompleted() throws Exception
324324
k3po.finish();
325325
}
326326

327+
@Test
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@Configuration("server.timeout.yaml")
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@Specification({
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"${net}/tools.call.elicit.after.result/client",
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"${app}/tools.call.elicit.after.result/server"})
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public void shouldCallToolElicitAfterResult() throws Exception
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{
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k3po.finish();
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}
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327337
@Test
328338
@Configuration("server.timeout.yaml")
329339
@Specification({

‎specs/binding-mcp.spec/src/main/scripts/io/aklivity/zilla/specs/binding/mcp/streams/application/tools.call.elicit.after.result/client.rpt‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,83 @@
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#
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# Copyright 2021-2024 Aklivity Inc
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#
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# Licensed under the Aklivity Community License (the "License"); you may not use
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# this file except in compliance with the License. You may obtain a copy of the
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# License at
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#
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# https://www.aklivity.io/aklivity-community-license/
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OF ANY KIND, either express or implied. See the License for the
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# specific language governing permissions and limitations under the License.
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#
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connect "zilla://streams/app0"
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option zilla:window 8192
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option zilla:transmission "half-duplex"
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write zilla:begin.ext ${mcp:beginEx()
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.typeId(zilla:id("mcp"))
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.lifecycle()
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.build()
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.build()}
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connected
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read zilla:begin.ext ${mcp:matchBeginEx()
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.typeId(zilla:id("mcp"))
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.lifecycle()
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.sessionId("session-1")
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.build()
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.build()}
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read notify LIFECYCLE_INITIALIZED
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connect await LIFECYCLE_INITIALIZED
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"zilla://streams/app0"
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option zilla:window 8192
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option zilla:transmission "half-duplex"
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write zilla:begin.ext ${mcp:beginEx()
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.typeId(zilla:id("mcp"))
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.toolsCall()
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.sessionId("session-1")
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.name("get_weather")
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.contentLength(59)
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.timeout(30000)
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.build()
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.build()}
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connected
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write '{'
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'"name":"get_weather",'
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'"arguments":'
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'{'
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'"location": "New York"'
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'}'
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'}'
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read '{'
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'"content":'
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'['
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'{'
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'"type": "text",'
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'"text": "Current weather in New York:\\nTemperature: 72°F\\nConditions: Partly cloudy"'
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'}'
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'],'
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'"isError": false'
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'}'
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read notify RESULT_DELIVERED
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write advised zilla:challenge ${mcp:matchChallengeEx()
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.typeId(zilla:id("mcp"))
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.elicitCreate()
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.id("1")
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.url("https://server.example.com/authorize?state=7f3a9b1c&redirect_uri=%s".formatted(http:encodeQuery("https://replace.me/callback")))
80+
.build()
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.build()}
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read abort

‎specs/binding-mcp.spec/src/main/scripts/io/aklivity/zilla/specs/binding/mcp/streams/application/tools.call.elicit.after.result/server.rpt‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,87 @@
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#
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# Copyright 2021-2024 Aklivity Inc
3+
#
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# Licensed under the Aklivity Community License (the "License"); you may not use
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# this file except in compliance with the License. You may obtain a copy of the
6+
# License at
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#
8+
# https://www.aklivity.io/aklivity-community-license/
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#
10+
# Unless required by applicable law or agreed to in writing, software
11+
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OF ANY KIND, either express or implied. See the License for the
13+
# specific language governing permissions and limitations under the License.
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#
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property serverAddress "zilla://streams/app0"
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accept ${serverAddress}
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option zilla:window 8192
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option zilla:transmission "half-duplex"
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accepted
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read zilla:begin.ext ${mcp:matchBeginEx()
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.typeId(zilla:id("mcp"))
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.lifecycle()
27+
.build()
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.build()}
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connected
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write zilla:begin.ext ${mcp:beginEx()
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.typeId(zilla:id("mcp"))
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.lifecycle()
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.sessionId("session-1")
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.build()
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.build()}
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write flush
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accepted
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read zilla:begin.ext ${mcp:matchBeginEx()
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.typeId(zilla:id("mcp"))
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.toolsCall()
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.sessionId("session-1")
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.name("get_weather")
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.contentLength(59)
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.build()
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.build()}
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connected
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read '{'
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'"name":"get_weather",'
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'"arguments":'
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'{'
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'"location": "New York"'
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'}'
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'}'
60+
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write flush
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# result delivered first — commits the response to application/json
64+
write '{'
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'"content":'
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'['
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'{'
68+
'"type": "text",'
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'"text": "Current weather in New York:\\nTemperature: 72°F\\nConditions: Partly cloudy"'
70+
'}'
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'],'
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'"isError": false'
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'}'
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write flush
75+
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read await RESULT_DELIVERED
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# illegal: elicitation challenge after the result has already been returned
79+
read advise zilla:challenge ${mcp:challengeEx()
80+
.typeId(zilla:id("mcp"))
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.elicitCreate()
82+
.id("1")
83+
.url("https://server.example.com/authorize?state=7f3a9b1c&redirect_uri=%s".formatted(http:encodeQuery("https://replace.me/callback")))
84+
.build()
85+
.build()}
86+
87+
write aborted

‎specs/binding-mcp.spec/src/main/scripts/io/aklivity/zilla/specs/binding/mcp/streams/network/tools.call.elicit.after.result/client.rpt‎

Lines changed: 119 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,119 @@
1+
#
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# Copyright 2021-2024 Aklivity Inc
3+
#
4+
# Licensed under the Aklivity Community License (the "License"); you may not use
5+
# this file except in compliance with the License. You may obtain a copy of the
6+
# License at
7+
#
8+
# https://www.aklivity.io/aklivity-community-license/
9+
#
10+
# Unless required by applicable law or agreed to in writing, software
11+
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12+
# WARRANTIES OF ANY KIND, either express or implied. See the License for the
13+
# specific language governing permissions and limitations under the License.
14+
#
15+
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connect "zilla://streams/net0"
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option zilla:window 8192
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option zilla:transmission "half-duplex"
19+
20+
write zilla:begin.ext ${http:beginEx()
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.typeId(zilla:id("http"))
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.header(":method", "POST")
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.header(":scheme", "http")
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.header(":authority", "localhost:8080")
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.header(":path", "/mcp")
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.header("content-type", "application/json")
27+
.header("accept", "application/json, text/event-stream")
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.header("mcp-protocol-version", "2025-11-25")
29+
.build()}
30+
31+
connected
32+
33+
write '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-11-25","capabilities":{"elicitation":{"url":{}}},"clientInfo":{"name":"test","version":"1.0"}}}'
34+
write close
35+
36+
read zilla:begin.ext ${http:matchBeginEx()
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.typeId(zilla:id("http"))
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.header(":status", "200")
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.header("content-type", "application/json")
40+
.header("mcp-session-id", "transport-1")
41+
.build()}
42+
43+
read '{"jsonrpc":"2.0","id":1,"result":{"protocolVersion":"2025-11-25","capabilities":{"prompts":{"listChanged":true},"resources":{"listChanged":true},"tools":{"listChanged":true}},"serverInfo":{"name":"zilla","version":"1.0"}}}'
44+
read closed
45+
read notify LIFECYCLE_INITIALIZING
46+
47+
connect await LIFECYCLE_INITIALIZING
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"zilla://streams/net0"
49+
option zilla:window 8192
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option zilla:transmission "half-duplex"
51+
52+
write zilla:begin.ext ${http:beginEx()
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.typeId(zilla:id("http"))
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.header(":method", "POST")
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.header(":scheme", "http")
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.header(":authority", "localhost:8080")
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.header(":path", "/mcp")
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.header("content-type", "application/json")
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.header("accept", "application/json, text/event-stream")
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.header("mcp-protocol-version", "2025-11-25")
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.header("mcp-session-id", "transport-1")
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.build()}
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64+
connected
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write '{"jsonrpc":"2.0","method":"notifications/initialized"}'
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write close
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read closed
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read notify LIFECYCLE_INITIALIZED
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72+
connect await LIFECYCLE_INITIALIZED
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"zilla://streams/net0"
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option zilla:window 8192
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option zilla:transmission "half-duplex"
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77+
write zilla:begin.ext ${http:beginEx()
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.typeId(zilla:id("http"))
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.header(":method", "POST")
80+
.header(":scheme", "http")
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.header(":authority", "localhost:8080")
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.header(":path", "/mcp")
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.header("content-type", "application/json")
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.header("accept", "application/json, text/event-stream")
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.header("mcp-protocol-version", "2025-11-25")
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.header("mcp-session-id", "transport-1")
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.header("content-length", "115")
88+
.build()}
89+
90+
connected
91+
92+
write '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"get_weather","arguments":{"location": "New York"}}}'
93+
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write close
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96+
read zilla:begin.ext ${http:matchBeginEx()
97+
.typeId(zilla:id("http"))
98+
.header(":status", "200")
99+
.header("content-type", "application/json")
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.build()}
101+
102+
read '{'
103+
'"jsonrpc":"2.0",'
104+
'"id":2,'
105+
'"result":'
106+
'{'
107+
'"content":'
108+
'['
109+
'{'
110+
'"type": "text",'
111+
'"text": "Current weather in New York:\\nTemperature: 72°F\\nConditions: Partly cloudy"'
112+
'}'
113+
'],'
114+
'"isError": false'
115+
'}'
116+
117+
read notify RESULT_DELIVERED
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119+
read aborted

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