Troubleshoot¶
Tool errors come back to the agent as text, so the agent usually tells you what went wrong. This page explains the common messages.
The server does not start¶
Run the command from your client configuration by hand. It prints the real error:
$ INDICO_URL=https://indico.cern.ch uvx --from git+https://github.com/vuillaut/indico-mcp indico-mcp --help
| Message | Fix |
|---|---|
Set INDICO_URL (one instance) ... or INDICO_INSTANCES |
Neither setting is present. Check the env block of your client configuration. |
INDICO_INSTANCES: 'x': expected name=https://host |
Each entry needs a lowercase name, =, and a URL starting with http:// or https://. |
uvx: command not found in Claude Desktop |
Put the full path of uvx in command. |
Errors from Indico¶
| Message | Meaning |
|---|---|
Indico redirected to the login page |
No token, an invalid token, or a token without the scope this call needs. |
HTTP 401 (authentication failed...) |
The token is wrong or revoked. |
HTTP 403 (forbidden...) |
Your account lacks rights on this event, or the token lacks a scope. Management actions need Everything (all methods); check-in needs Registrants. |
HTTP 404 (not found) |
Wrong id, or an id of the wrong kind. See Ids. |
event 123 not found or not visible to this user |
The event is protected and there is no token, or it does not exist. |
Errors from the server¶
| Message | Meaning |
|---|---|
pass instance, one of [...] |
Several instances and no default. Name one, or set INDICO_DEFAULT_INSTANCE. |
unknown instance 'x' |
The name or host is not configured. The message lists what is. |
the form has no field(s) [...] |
The Indico page differs from what the server expects, usually after an Indico upgrade. Nothing was changed. Please open an issue with the Indico version. |
Indico rejected the form: field: message |
Indico refused the values, for example a talk longer than its session block. |
give the local time in the event's timezone, without an offset |
Pass 2026-10-05T14:30, not 2026-10-05T14:30+02:00. |
removing this ... deletes data, and deletes are disabled |
See Limit what the agent can do. |
Times look shifted¶
All times are in the event's timezone. Search results are the exception: Indico returns them in UTC, and the result says "timezone": "UTC". Call indico_get_event for local times.
A new talk got the wrong id¶
indico_create_contribution finds the new talk's id by title, because Indico does not return it. If two talks have the same title, it picks the newest. Check with indico_list_contributions.