Deprecating My Symfony Profiler MCP Bundle: Right About the Problem, Half-Wrong About the Solution

Description and use

The mcp-profiler-bundle exposed Symfony Profiler data via MCP but lacked agent guidance and had security flaws. Symfony AI Mate introduced a CLI with Agent Skills, enhancing usability and safety.

Problem

Developers needed an AI agent to read Symfony Profiler data, but the initial bundle exposed data without guiding the agent on how to use it, leading to low adoption and security issues.

Outcome

The bundle demonstrated the problem of exposing profiler data but failed to provide guidance (skills) and had security and protocol issues. Symfony’s official solution addressed these gaps, leading to higher agent adoption and safer data handling.

Workflow

• 1. Build MCP server exposing profiler tools via stdio.
• 2. Deploy bundle and run bin/console mcp:server:run to start server.
• 3. Agents call tools via MCP JSON‑RPC.
• 4. Observe low agent usage and security concerns.
• 5. Symfony releases official MCP SDK and AI Mate with CLI and Agent Skills.
• 6. Deprecated bundle and shift to Mate’s approach.

Evidence

Mate’s answer is Agent Skills — SKILL.md files installed into .agents/skills/ that say when to reach for which tool.

Source

The bundle had no redaction and exposed cookies, headers, and env vars.

Source

Symfony AI Mate shipped its first release on 23 December 2025, about nine months after my 0.1.0.

Source