Phase 5: MCP tool capability index -- context-aware tool loading

[AlexMikhalev]

Parent Epic

Part of #692 (Operational Skill Store)

Summary

Extend the MCP server to expose a tool capability index that returns only relevant tool definitions for the current task, using Aho-Corasick automata to match task descriptions against tool capability descriptions. This solves "catalog bloat" -- instead of stuffing all tool schemas into context, load only what is needed.

What Changes

Tool capability index in terraphim_mcp_server

• Each registered MCP tool gets a capability description indexed in the KG
• Query API matches task description against tool capabilities
• Returns ranked list of relevant tools with their schemas

CLI

terraphim-agent tools relevant "fix the broken data pipeline"
# Returns: ssh, systemctl, config-edit, log-search (4 of 47 available tools)

MCP resource

Expose as MCP resource so agents can query before requesting tool definitions:

terraphim://tools/relevant?query=deploy+config

Affected Crates

• terraphim_mcp_server (tool index resource)
• terraphim_automata (capability matching)

Dependencies

• Existing Aho-Corasick infrastructure
• MCP server already running (feat: Add context-hub haystack connector #651 context-hub haystack connector for pattern)

Acceptance Criteria

• Tool capability descriptions indexed in KG
• Query returns ranked relevant tools
• MCP resource endpoint functional
• CLI tools relevant command works
• Reduces token usage compared to loading all tool schemas
• Benchmarks showing sub-100ms query time via automata