The Night Red Squiggles Filled My MCP Config, and What I Checked Before Editing
Red squiggles across your MCP config don't mean the servers are down. Schema validation in the editor answers a different question than the runtime does. Here's the order I now follow, starting with the status rings in /mcp.
When a session starts with MCP tools missing, where do you stop?
When MCP initialization fails at startup, the agent quietly falls back to other means and keeps going. Here is a small script that asks your servers directly which tools they expose, plus the three branches I decided on in advance for when something is missing.
Adding MCP Servers Without Opening the Config File: The agy mcp Subcommand
Antigravity CLI 1.1.16, released on August 20, adds an mcp subcommand so you can register and toggle MCP servers without hand-editing JSON. Here is how to add stdio and HTTP servers, isolate a misbehaving one, and script your whole setup so it travels to a new machine.
Find the one broken MCP entry before Antigravity starts, with 40 lines of Node
A single typo in your MCP settings can take every server down with it. Here is a small preflight script that catches the mistakes statically, the real output from a deliberately broken config, and the duplicate-key trap that JSON hides from you.
The MCP Server I Thought I Killed Was Still Holding the Port: 84 Teardown Trials
Closing a session should stop the MCP servers it started. Across 84 trials of four teardown strategies, a process-group SIGTERM left zero orphans — until the child called setsid, at which point it left 100%. Includes a full descendant-sweep implementation.
Startup Dropped to 3ms, and the First Turn Saw Zero Tools
Non-blocking MCP loading cut startup from 2,907ms to 3ms. The wait did not disappear — it moved into the first turn. Here is where it went, measured, plus a readiness gate that waits only for what a turn actually needs.
I Measured Before Writing a Number: MCP Connect and Tool Calls Differed by 486x
Antigravity 2.4.3 lets you set a timeout per MCP server. To find a defensible number I built a stdio server, measured each boundary separately, and found why a single value cannot cover both.
I Copied the Same agent.md Into Another Repo and It Quietly Did a Different Job
CLI 1.1.6 lets you carry agent definitions around as files. I dropped one definition into eight repos, built a preflight that resolves its declared capabilities before the agent runs, and measured it against a naive checker.
Three Tools Named read_file: Catching MCP Name Collisions Before Startup
Bundle enough MCP servers and tool names collide quietly. Here is what a real 5-server, 21-tool setup measured at 43% collision, plus a Python preflight that catches them before startup and assigns deterministic aliases.
Stop Antigravity From Writing Outdated API Code — Three Ways to Hand It Fresh Library Docs
A practical workflow for keeping Antigravity's AI on the latest library APIs — using Context7 MCP, direct doc URLs, and AGENTS.md to anchor the agent to your real version stack.
Complete Troubleshooting Guide for Antigravity MCP Connection Errors
Master MCP connection troubleshooting with step-by-step diagnosis, authentication fixes, and debugging techniques for seamless integration.
When an Unresponsive MCP Server Freezes Your Agent: Separate Timeouts for Connect, List, and Call
Antigravity CLI 1.1.3 closed the case where an unresponsive MCP server stalls an agent forever, by adding timeouts to connect, list-tools, and call-tool. This walks through why the three boundaries fail differently, and builds a defensive wrapper with a circuit breaker and failure-only notifications, backed by working code and a week of overnight runs.