Pi extension registers 0 tools — routing block tells LLM to use ctx_execute/ctx_search but they don't exist

[leing2021]

Bug Summary

The Pi extension (build/pi-extension.js) injects a routing block that instructs the LLM to use ctx_execute, ctx_search, ctx_batch_execute, ctx_fetch_and_index, etc. — but none of these tools are registered via pi.registerTool().

The LLM sees the routing directive but cannot find the tools, so it falls back to ignoring the block entirely. This makes context-mode a pure cost with zero benefit in Pi.

Evidence

What the Pi extension DOES register:

pi.on("session_start", ...)        ✅ session tracking
pi.on("tool_call", ...)            ✅ event capture
pi.on("tool_result", ...)          ✅ event capture
pi.on("before_agent_start", ...)   ✅ routing block injection
pi.registerCommand("ctx-stats")    ✅ command
pi.registerCommand("ctx-doctor")   ✅ command

What the Pi extension DOES NOT register:

pi.registerTool("ctx_execute")         ❌ MISSING
pi.registerTool("ctx_execute_file")    ❌ MISSING
pi.registerTool("ctx_search")          ❌ MISSING
pi.registerTool("ctx_batch_execute")   ❌ MISSING
pi.registerTool("ctx_fetch_and_index") ❌ MISSING
pi.registerTool("ctx_index")           ❌ MISSING
pi.registerTool("ctx_doctor")          ❌ MISSING (only a command, not a tool)
pi.registerTool("ctx_stats")           ❌ MISSING (only a command, not a tool)
pi.registerTool("ctx_purge")           ❌ MISSING
pi.registerTool("ctx_upgrade")         ❌ MISSING
pi.registerTool("ctx_insight")         ❌ MISSING

Impact measurements (18 sessions over 2 days):

Metric	Value
System prompt cost per window	~2,500 tokens (routing block + 12 skill descriptions + MCP tool stubs)
Tool calls via ctx_* tools	0 (never called)
Tokens saved by context-mode	0
Knowledge base events recorded	447 (never retrieved)
Net ROI	Negative

Root cause

The server.bundle.mjs implements 13 MCP tools via the MCP protocol (stdio JSON-RPC), which works for Claude Code and other MCP hosts. But Pi extensions use pi.registerTool() API instead of MCP protocol. The Pi extension file (pi-extension.js) never bridges these two worlds.

Suggested fix

Add pi.registerTool() calls in pi-extension.js that wrap the server-side tool handlers. Example pattern from Pi docs:

pi.registerTool({
  name: "ctx_execute",
  label: "ctx_execute",
  description: "Execute code and index output for later search",
  parameters: Type.Object({
    language: Type.String({ description: "Programming language" }),
    code: Type.String({ description: "Code to execute" }),
  }),
  async execute(toolCallId, params, signal, onUpdate, ctx) {
    // Bridge to the existing server-side handler
    const result = await serverHandler.executeCode(params);
    return {
      content: [{ type: "text", text: result }],
      details: {},
    };
  },
});

This needs to be done for all 13 tools defined in server.bundle.mjs.

Environment

• context-mode: 1.0.111
• pi: 0.73.0
• OS: macOS (Apple Silicon)
• Node: v22.20.0