diff --git a/.agents/mcp/codex.config.toml b/.agents/mcp/codex.config.toml
index a310b62b..630a2537 100644
--- a/.agents/mcp/codex.config.toml
+++ b/.agents/mcp/codex.config.toml
@@ -1,3 +1,3 @@
 [mcp_servers.tc39]
 command = "npx"
-args = ["-y", "tc39-mcp@0.4.0"]
+args = ["-y", "tc39-mcp@0.5.0"]
diff --git a/.agents/mcp/mcp.json b/.agents/mcp/mcp.json
index 4224e5ac..b38ad50f 100644
--- a/.agents/mcp/mcp.json
+++ b/.agents/mcp/mcp.json
@@ -2,7 +2,7 @@
   "mcpServers": {
     "tc39": {
       "command": "npx",
-      "args": ["-y", "tc39-mcp@0.4.0"]
+      "args": ["-y", "tc39-mcp@0.5.0"]
     }
   }
 }
diff --git a/.agents/skills/gocciascript-issue-validation/SKILL.md b/.agents/skills/gocciascript-issue-validation/SKILL.md
index 1ace559b..6b8c05da 100644
--- a/.agents/skills/gocciascript-issue-validation/SKILL.md
+++ b/.agents/skills/gocciascript-issue-validation/SKILL.md
@@ -9,7 +9,7 @@ Project-specific validation rules for GocciaScript issues. Use this skill with t
 
 ## Spec Lookup
 
-For ECMA-262 or ECMA-402 semantics, use the pinned `tc39-mcp@0.4.0` server from the project MCP config under `.agents/mcp/` when it is available. `tc39-mcp` spec-reading tools default to ECMA-262, so pass the spec explicitly for the standard you are checking:
+For ECMA-262 or ECMA-402 semantics, use the pinned `tc39-mcp@0.5.0` server from the project MCP config under `.agents/mcp/` when it is available. `tc39-mcp` spec-reading tools default to ECMA-262, so pass the spec explicitly for the standard you are checking:
 
 - ECMA-262 language/core built-ins: `spec: "262"`
 - ECMA-402 Intl behavior: `spec: "402"`
diff --git a/.mcp.example.json b/.mcp.example.json
index 4224e5ac..b38ad50f 100644
--- a/.mcp.example.json
+++ b/.mcp.example.json
@@ -2,7 +2,7 @@
   "mcpServers": {
     "tc39": {
       "command": "npx",
-      "args": ["-y", "tc39-mcp@0.4.0"]
+      "args": ["-y", "tc39-mcp@0.5.0"]
     }
   }
 }
diff --git a/AGENTS.md b/AGENTS.md
index 613b918f..c50c13b6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -34,7 +34,7 @@ For ECMAScript or ECMA-402 behavior, use the project TC39 MCP server before fall
   "mcpServers": {
     "tc39": {
       "command": "npx",
-      "args": ["-y", "tc39-mcp@0.4.0"]
+      "args": ["-y", "tc39-mcp@0.5.0"]
     }
   }
 }