Limits and errors

Asking questions

Question timeout: 5 minutes. A question that takes longer returns an error and closes the chat turn.
Result rows: Up to 100 rows inline, with truncated marking a capped result set. For more, narrow the question or ask for aggregates.
Zero rows: Not an error. The query ran and matched nothing.
Null results: The SQL was not executed. On a schema-only project that is always the case: see Connect a warehouse or upload DDL.
Not answerable: The approved plan cannot run against the current ontology or data. Retrying the same question will not help. See ask_question.
Model overloaded: When the model is briefly overloaded or rate-limited, the tool returns a plain-language message rather than a raw error. Retry in a moment.

Source schema detail: get_source_schema details at most 20 tables per call. Call it again for more, or use cassis schema pull for a full local snapshot.
Error convention: Every tool reports a failure as an error key in place of its normal fields, rather than raising.
Roles: Reads need an active account in the project’s organization. update_issue_status needs the editor or admin role. Chats are author-only over MCP: an org admin can read a colleague’s chat in the web app but not through the server.
Idle sessions: A session with no activity for 30 minutes expires. A client that reconnects initializes a fresh session, so long-running agents are unaffected.
Credential expiry: Expired or revoked credentials return HTTP 401. OAuth clients re-run the flow automatically; an API key has to be replaced.
Unreachable project: Querying a project the authenticated user cannot access returns an error rather than an empty result.

Code	Meaning
`0`	Success. For `check`, advisory warnings never change this. For `test`, every probe completed, whatever the outcome
`1`	The thing failed on its own terms: validation findings, failed eval cases, a duplicate eval case, a case id that does not exist, a failed detection run, or `verify` stopping at a failing step
`2`	Usage error: missing API key or project, no ontology directory, an unreadable file, or a tree over the size limits
`3`	Transport or API error: unreachable API, invalid key, inaccessible project, another run already active, out of credits, or a timeout
`130`	Ctrl-C during `eval run`. The run is cancelled server-side

Tree size: Commands that send the local tree accept up to 20,000 ontology files (YAML plus domains/**/README.md) and 100 MB total, sized for roughly 10,000 modeled tables. Beyond that the CLI fails fast with exit 2 before uploading anything. If you hit it, check --base-path. On cassis-cli older than 1.5.1 the client stops at the previous ceiling of 2,000 files and 5 MB, whatever the server accepts.
DDL size: cassis schema push sends the file inline, and the API rejects a DDL over 10 MB. A whole-warehouse export above that has to be pushed schema by schema, which a push handles: it updates only the schemas in the file. See Review data-source changes.
Eval run timeout: 30 minutes by default, --timeout to change it. The run continues server-side if the CLI stops waiting.
Detection run timeout: 10 minutes for schema push, same behavior.
Probe duration: ontology test is one full agent run per question, roughly 30 to 90 seconds each.

Failure is safe: On malformed YAML or a missing required field, Cassis keeps its previous ontology. Nothing is half-imported.
Idempotence: Re-importing or re-uploading identical content creates no new version.
Complete replacement: Every import and publish replaces the complete ontology. This is why a project should have one editing path: see Choose how your ontology is managed.

Failure-by-failure fixes for the git loop are in Troubleshoot git and publishing.