Streamable HTTP connection leak #266

Closed
#268
Closed
Streamable HTTP connection leak#266
#268
Assignees
4t145
Labels
T-bugBug fixes and error corrections

Description

@howardjohn
howardjohn
opened on Jun 17, 2025

Describe the bug
Connections are not closed using streamable HTTP

To Reproduce
Steps to reproduce the behavior:

  1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
  2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.

This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:

cargo run --example clients_streamable_http

diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}

Expected behavior
Connection is reused or closed

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    , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
     blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

    Skip to content
    Streamable HTTP connection leak #266
    Closed
    #268
    Closed
    Streamable HTTP connection leak#266
    #268
    Assignees
    4t145
    Labels
    T-bugBug fixes and error corrections
    Description
    @howardjohn
    howardjohn
    opened on Jun 17, 2025
    Describe the bug
    
Connections are not closed using streamable HTTP
    To Reproduce
    
Steps to reproduce the behavior:
    1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
    2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.
    This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:
    cargo run --example clients_streamable_http

    diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}
    Expected behavior
    
Connection is reused or closed
    Metadata
    Metadata
    Assignees
    Labels
    T-bugBug fixes and error corrections
    Type
    No type
    Projects
    No projects
      Milestone
      No milestone
      Relationships
      None yet
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      No branches or pull requests
      Issue actions
      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

      Skip to content
      Streamable HTTP connection leak #266
      Closed
      #268
      Closed
      Streamable HTTP connection leak#266
      #268
      Assignees
      4t145
      Labels
      T-bugBug fixes and error corrections
      Description
      @howardjohn
      howardjohn
      opened on Jun 17, 2025
      Describe the bug
      
Connections are not closed using streamable HTTP
      To Reproduce
      
Steps to reproduce the behavior:
      1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
      2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.
      This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:
      cargo run --example clients_streamable_http

      diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}
      Expected behavior
      
Connection is reused or closed
      Metadata
      Metadata
      Assignees
      Labels
      T-bugBug fixes and error corrections
      Type
      No type
      Projects
      No projects
        Milestone
        No milestone
        Relationships
        None yet
        Development
        No branches or pull requests
        Issue actions
        
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

        Skip to content
        Streamable HTTP connection leak #266
        Closed
        #268
        Closed
        Streamable HTTP connection leak#266
        #268
        Assignees
        4t145
        Labels
        T-bugBug fixes and error corrections
        Description
        @howardjohn
        howardjohn
        opened on Jun 17, 2025
        Describe the bug
        
Connections are not closed using streamable HTTP
        To Reproduce
        
Steps to reproduce the behavior:
        1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
        2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.
        This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:
        cargo run --example clients_streamable_http

        diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}
        Expected behavior
        
Connection is reused or closed
        Metadata
        Metadata
        Assignees
        Labels
        T-bugBug fixes and error corrections
        Type
        No type
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

          Skip to content
          Streamable HTTP connection leak #266
          Closed
          #268
          Closed
          Streamable HTTP connection leak#266
          #268
          Assignees
          4t145
          Labels
          T-bugBug fixes and error corrections
          Description
          @howardjohn
          howardjohn
          opened on Jun 17, 2025
          Describe the bug
          
Connections are not closed using streamable HTTP
          To Reproduce
          
Steps to reproduce the behavior:
          1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
          2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.
          This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:
          cargo run --example clients_streamable_http

          diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}
          Expected behavior
          
Connection is reused or closed
          Metadata
          Metadata
          Assignees
          Labels
          T-bugBug fixes and error corrections
          Type
          No type
          Projects
          No projects
            Milestone
            No milestone
            Relationships
            None yet
            Development
            No branches or pull requests
            Issue actions
            
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

            Skip to content
            Streamable HTTP connection leak #266
            Closed
            #268
            Closed
            Streamable HTTP connection leak#266
            #268
            Assignees
            4t145
            Labels
            T-bugBug fixes and error corrections
            Description
            @howardjohn
            howardjohn
            opened on Jun 17, 2025
            Describe the bug
            
Connections are not closed using streamable HTTP
            To Reproduce
            
Steps to reproduce the behavior:
            1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
            2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.
            This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:
            cargo run --example clients_streamable_http

            diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}
            Expected behavior
            
Connection is reused or closed
            Metadata
            Metadata
            Assignees
            Labels
            T-bugBug fixes and error corrections
            Type
            No type
            Projects
            No projects
              Milestone
              No milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              Streamable HTTP connection leak #266
              Closed
              #268
              Closed
              Streamable HTTP connection leak#266
              #268
              Assignees
              4t145
              Labels
              T-bugBug fixes and error corrections
              Description
              @howardjohn
              howardjohn
              opened on Jun 17, 2025
              Describe the bug
              
Connections are not closed using streamable HTTP
              To Reproduce
              
Steps to reproduce the behavior:
              1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
              2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.
              This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:
              cargo run --example clients_streamable_http

              diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}
              Expected behavior
              
Connection is reused or closed
              Metadata
              Metadata
              Assignees
              Labels
              T-bugBug fixes and error corrections
              Type
              No type
              Projects
              No projects
                Milestone
                No milestone
                Relationships
                None yet
                Development
                No branches or pull requests
                Issue actions
                
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

                Skip to content
                Streamable HTTP connection leak #266
                Closed
                #268
                Closed
                Streamable HTTP connection leak#266
                #268
                Assignees
                4t145
                Labels
                T-bugBug fixes and error corrections
                Description
                @howardjohn
                howardjohn
                opened on Jun 17, 2025
                Describe the bug
                
Connections are not closed using streamable HTTP
                To Reproduce
                
Steps to reproduce the behavior:
                1. Run a streamable HTTP server with this library: cargo run --example servers_counter_streamhttp
                2. Connect to it and call tools multiple times. Each tool call will open a new connection that is never closed.
                This is reproducible with MCP inspector and with the example client. I changed the client to send many tool calls:
                cargo run --example clients_streamable_http

                diff --git a/examples/clients/src/streamable_http.rs b/examples/clients/src/streamable_http.rs
index 634ec61..577613d 100644
--- a/examples/clients/src/streamable_http.rs+++ b/examples/clients/src/streamable_http.rs@@ -4,6 +4,7 @@ use rmcp::{
model::{CallToolRequestParam, ClientCapabilities, ClientInfo, Implementation},
transport::StreamableHttpClientTransport,
};
+use std::time::Duration;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
#[tokio::main]
@@ -37,13 +38,16 @@ async fn main() -> Result<()> {
let tools = client.list_tools(Default::default()).await?;
tracing::info!("Available tools: {tools:#?}");
- let tool_result = client- .call_tool(CallToolRequestParam {- name: "increment".into(),- arguments: serde_json::json!({}).as_object().cloned(),- })- .await?;- tracing::info!("Tool result: {tool_result:#?}");+ for i in 0..100 {+ let tool_result = client+ .call_tool(CallToolRequestParam {+ name: "increment".into(),+ arguments: serde_json::json!({}).as_object().cloned(),+ })+ .await?;+ tracing::info!("Tool result: {tool_result:#?}");+ tokio::time::sleep(Duration::from_secs(1)).await;+ }
client.cancel().await?;
Ok(())
}
                Expected behavior
                
Connection is reused or closed
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                T-bugBug fixes and error corrections
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