AI coding tool errors, decoded by exact message
Paste the error from Claude Code, Codex, Antigravity, Gemini CLI, Copilot, MCP, OAuth, sandbox, or deployment logs. Each page explains what the exact message means and the safest fix path.
Claude Code
You've hit your session limit / weekly limit - Claude Code
Your Claude Code subscription or organization allowance is exhausted for the current rolling window. This is account quota, not a local project bug.
Prompt is too long - Claude Code context window
The conversation, attached files, memory files, and tool definitions no longer fit inside the selected model context window.
Not logged in - Please run /login - Claude Code
Claude Code cannot use the current local credential. The token may be expired, revoked, tied to a disabled organization, or shadowed by the wrong API key environment variable.
API Error: Repeated 529 Overloaded errors - Claude Code
Claude Code reached the model service, but the provider is overloaded, timing out, or returning a transient server error.
MCP servers failed to connect - Claude Code
Claude Code started, but one or more MCP server processes or remote transports failed during discovery, authentication, schema validation, or streaming.
OpenAI Codex
code=3221225477 - Codex Windows desktop crashes on launch
The Windows desktop app exits before the UI is usable. Reports connect this code with native process startup, sandbox initialization, or Windows environment issues.
CreateProcessWithLogonW failed: 5 - Codex Windows sandbox
Codex attempted to start a sandboxed command on Windows and received access denied from the operating system.
SetNamedSecurityInfoW failed: 5 - Codex WindowsApps ACL sandbox failure
Codex tried to adjust read permissions for packaged resources under WindowsApps and Windows denied the ACL update.
MCP auth session does not refresh - Codex OAuth
The browser OAuth flow succeeded, but Codex continued using a stale or invalid MCP token for the routed server.
Codex desktop unresponsive with long threads and MCP auto-start duplicates
The desktop app becomes slow or unresponsive during large agent sessions, often with long histories, broad workspaces, or repeated MCP startup.
Google Antigravity
Agent execution terminated due to error - Google Antigravity
The Antigravity agent runner stopped before completing the task. The cause can be provider reachability, model routing, MCP tool failure, or stale local auth.
Error calling initialize: EOF - Antigravity MCP
Antigravity opened an MCP server connection but the process or transport ended before JSON-RPC initialization completed.
Failed to exchange authorization code for token - Antigravity
The browser OAuth step returned a code, but Antigravity could not exchange it for a usable local token.
Failed to get OAuth token: state syncing error: key not found - Antigravity
The local token store and the active Google session are out of sync. The IDE can show a signed-in state while background services cannot fetch credentials.
Command exits 0 but captures zero stdout/stderr - Antigravity terminal blindness
The command may run, but the agent cannot observe terminal output, so it waits, repeats, or makes decisions without the actual result.
Stuck on Running / Generating - Google Antigravity agent not responding
A tool call, command, or model response did not complete from the agent manager point of view.
Antigravity doesn't support MCP OAuth specifications
Google Cloud documents a current Antigravity limitation: some remote MCP OAuth flows cannot authenticate because the client cannot provide the required client identity.
Gemini CLI
401 / 403 PERMISSION_DENIED - Gemini CLI authentication errors
Gemini CLI cannot authenticate to the Google AI API, or the project behind the key is not allowed to call the required service.
429 Too Many Requests / quota exceeded - Gemini CLI
The Google account, project, API key, or model quota used by Gemini CLI has hit a rate or daily usage limit.
DISCONNECTED - Gemini CLI MCP server is not connected or has errors
Gemini CLI registered an MCP server, but the server is not usable for tool calls.
GitHub Copilot
MCP server slow to connect - GitHub Copilot coding agent
A repository-configured MCP server is available to the coding agent, but startup or discovery is too slow or fails.
frontmatter parse error with UTF-8 BOM - GitHub Copilot skill files
A skill or instruction file includes a byte order mark or malformed YAML frontmatter, so Copilot cannot parse it correctly.
MCP
MCP server crashed unexpectedly
The MCP host launched the server, but the subprocess exited or the remote transport closed before tools could be used.
Rate limit exceeded - MCP tool call
The MCP server is reachable, but the upstream API or provider rejected calls because the current token or IP exceeded a rate limit.
Invalid file permission - MCP filesystem or design tool
The MCP server tried to read or write a path or remote resource outside its allowed permissions.
Missing environment variable - MCP server startup
The MCP config references a server that needs secrets or settings, but the host process did not inherit them.
GitHub MCP Rate limit exceeded
An MCP server calling GitHub has exhausted REST, GraphQL, search, or secondary abuse-protection limits.
Deployment
Rollup failed to resolve import - Vite / Vercel deployment
The production build cannot resolve a module path that worked in local dev, commonly after AI-generated file moves or path aliases.
vite: not found / tsc: not found after NODE_ENV=production in Docker
The Docker build skipped devDependencies before running the frontend or TypeScript build.
Environment variables not working in Cloudflare Workers / wrangler
A variable available in local dev is not available in the Worker runtime or production build.