Error messages

What common messages mean and what to do about them.

Connection and service

You see	Meaning	What to do
`Can't reach the Syntic server — check your internet (…) · retrying in 4s · attempt 2/10`	The request could not get through. Syntic Code retries up to 10 times with a countdown; the reason in brackets says why (for example connection refused).	Check your connection, VPN or proxy. Nothing to do if it recovers.
`Could not reach the Syntic server after 10 attempts`	Every retry failed.	Fix the connection and send your message again. See proxies.
`No reply from the Syntic server for 14s — still waiting`	Connected, but the reply has not started yet. If it does not start within 90 seconds, the request is retried.	Usually just wait. Press `Esc` to stop.
`Rate limited — retrying in …`	You hit a short-term rate limit. It retries on its own.	Wait.
`The service stayed busy (overloaded or rate-limiting) through several retries. Wait a minute and send again, or pick another model with /model.`	The model stayed busy.	Wait a minute, or switch model. A `fallbackModel` setting switches automatically.
`The server returned HTTP 404 …` and other HTTP errors	The platform refused the request. The details follow.	Check `syntic --version` is current; try again.
`Your session has expired. Run syntic login to reconnect billing.`	Your sign-in is no longer valid.	`syntic login`.
Plan refusals (“Your account is a free one…”, “Your plan isn’t active…”)	Your plan does not cover Syntic Code right now.	See Plans & models.

Unattended runs (-p, background sessions) give up after 10 minutes of retry waits in total (SYNTIC_RETRY_WAIT_LIMIT_SECS).

You see	Meaning	What to do
`Permission denied: requires interactive approval, which is unavailable in this non-interactive run (…)`	A `-p` or background run hit something that needs your OK; nobody was there to answer.	Allow it up front with `--allowed-tools` or `--permission-mode`, or run interactively.
`Permission denied: Tool 'Bash' is denied by a saved decision` (or by a rule)	A deny rule matched. Deny rules win in every mode.	Check `/permissions` → Deny for the rule and its file.
`Tool '…' blocked by --disallowedTools`	The run was started with that tool blocked.	Remove it from `--disallowed-tools`.
Auto mode asks with a reason such as “it pushes to or changes a remote repository”	One of the built-in high-impact checks.	Approve if you meant it. These checks cannot be turned off.
”Syntic’s command safety check flagged this as critical and it will not be run”	A catastrophic command (such as deleting system folders) was refused outright.	Nothing to do; this is intentional.

You see	Meaning
`Refusing to edit …` / `Refusing to overwrite …`	The agent tried to change a file it had not read in this session. It reads the file and tries again.
A file changed since it was last read	You (or another program) edited the file after the agent read it, so its change was refused to protect yours. It re-reads and tries again.
`old_string found 2 times in …`	An edit was ambiguous. The agent adds more surrounding text or uses replace-all.
`old_string not found in …`	The text to replace is not in the file (often because the file changed).
`File not found: …`	Wrong path.
`… appears to be a binary file and cannot be read as text`	The file is binary (or in an encoding that is not UTF-8).
A write outside the working folders is refused	Add the folder with `/add-dir` if the agent should work there.

You see	Meaning
`Command did not finish within 2000 ms. Raise the timeout value or run it with run_in_background …`	A shell command hit its timeout. The agent can retry with a longer timeout or in the background.
Output ends with a note that the rest was saved to a file	The output was over 30,000 characters; the agent can read the full file.
`Tool '…' not found`	The model asked for a tool that does not exist in this session (perhaps `--tools` left it out).
`Invalid input for tool '…'`	The model sent malformed input; it usually corrects itself on the next step.
`Connection failed: … Check if the URL is correct.` (web fetch)	The page could not be reached.

You see	Meaning
`Unknown --output-format 'xml'. Use one of: text, json, stream-json.`	Typo in a flag value (exit code 2).
`--output-format stream-json requires --verbose`	Add `--verbose`.
`Unknown --permission-mode '…'`	Use `default`, `acceptEdits`, `auto`, `plan`, `bypassPermissions` or `dontAsk`.
`Invalid --session-id: '…' is not a valid UUID`	Session ids must be UUIDs.
`Invalid --settings: invalid settings JSON …`	The `--settings` value or file is not valid JSON.
`No previous session to continue in this project; starting a new session.`	`-c` found nothing to continue here.
`Unknown command: /… Run syntic interactively and type /help to list commands.`	An unknown slash command in a `-p` prompt.
`The /compact command is only available in an interactive session, not in --print mode.`	Some commands need the interactive screen.
An error for a word like `syntic install` or `syntic plugins`	That command does not exist; the message names the right one (`syntic update`, `syntic plugin`).

You see	Meaning and fix
A server shows “not connected” in `/mcp` with a reason	The server failed to start or answer. `syntic mcp list --check` tests local servers; `--mcp-debug` logs details.
A server “needs sign-in”	Press `Enter` on it in `/mcp`, or run `syntic mcp login <name>`.
`'…' sends its own Authorization header from its config, so it does not use sign-in`	The server is configured with a header, so `mcp login` is not needed.
`Allow it to start? [y/N]` before the session opens	A project server needs your approval the first time.
`Could not parse --mcp-config JSON …`	The value or file is not valid JSON; those servers are skipped.

Still stuck? Run with --debug, reproduce the problem, and save a report with /feedback. See Troubleshooting.