From c3dd4efe82d47930cae33893b01d4085512f615e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alejandro=20Guti=C3=A9rrez?=
 <35082514+alezmad@users.noreply.github.com>
Date: Thu, 9 Apr 2026 02:16:00 +0100
Subject: [PATCH] feat(cli): enforce context:fork via Agent tool instruction in
 prompts/get

Claude Code's MCP prompts path doesn't support the context field
natively. When a skill has context:"fork", prepend an instruction
telling the model to use the Agent tool with the specified agent
type and model.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 apps/cli/src/mcp/server.ts | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/apps/cli/src/mcp/server.ts b/apps/cli/src/mcp/server.ts
index 6084013..78d555f 100644
--- a/apps/cli/src/mcp/server.ts
+++ b/apps/cli/src/mcp/server.ts
@@ -336,6 +336,17 @@ Your message mode is "${messageMode}".
       if (manifest.argument_hint) fm.push(`argument-hint: "${manifest.argument_hint}"`);
       fm.push("---\n");
       if (fm.length > 3) content = fm.join("\n") + content;
+
+      // Enforce context:fork via Agent tool instruction — Claude Code's MCP prompts
+      // path doesn't support the context field natively, so we instruct the model.
+      if (manifest.context === "fork") {
+        const agentType = manifest.agent || "general-purpose";
+        const modelHint = manifest.model ? `, model: "${manifest.model}"` : "";
+        const toolsHint = manifest.allowed_tools?.length
+          ? `\nOnly use these tools: ${manifest.allowed_tools.join(", ")}.`
+          : "";
+        content = `IMPORTANT: Execute this skill in an isolated sub-agent. Use the Agent tool with subagent_type="${agentType}"${modelHint}. Pass the full instructions below as the agent prompt.${toolsHint}\n\n` + content;
+      }
     }
 
     return {