> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fincept.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Errors

> HTTP errors from the endpoint and error codes inside result envelopes.

## HTTP errors

These stop a request before any tool runs. Clients handle most of them.

| Status | Code | Meaning | Fix |
| - | - | - | - |
| `401` | `session_expired`, `session_revoked` | Missing, expired or revoked token. `WWW-Authenticate` carries `error="invalid_token"` and the OAuth metadata URL. | The client refreshes or signs in again. |
| `402` | `entitlement_required` | The account has no active plan. | Buy or renew a plan. |
| `403` | `upgrade_required` | The plan does not include Fincept MCP. | Upgrade to Exclusive Pro. |
| `429` | `rate_limited` | More than 120 requests a minute. `Retry-After` gives the wait. | Back off and retry. |

## Envelope errors

A tool that runs but cannot answer returns an envelope with `status: "error"`, `isError: true` and one of these codes in `error.code`.

| Code | Meaning |
| - | - |
| `validation_failed` | Arguments do not match the tool's schema, or a `$fincept` reference failed. The message names the field. |
| `upgrade_required` | This tool, or an option of it, needs a feature or capability the plan does not include. |
| `quota_exceeded` | A plan quota is reached, such as the number of watchlists or portfolios. |
| `insufficient_credits` | Not enough credits for a paid tool. |
| `spend_cap_reached` | The daily credit cap or the hourly cap for this action is reached. |
| `not_found` | The item does not exist or belongs to another account, or a stored result expired. |
| `timeout` | The call ran past its time limit. |
| `busy` | The engine (Fincept Stats, Forecast, Allocation, Portfolio Optimizer or Quant) has no free worker. Retry in a few seconds. |
| `model_failed` | An engine computation (a model fit, an optimisation, a forecast) failed on this data. The hint suggests what to change. |
| `unavailable` | A Fincept service could not be reached. Retry later. |

Other codes come straight from the service that refused, with a `message` and often a `hint`; agents should read and relay them.

## Unknown tools

Calling a name the catalog does not have is a JSON-RPC error (`unknown tool`), not an envelope. Use `fincept_search_tools` to find the right name.


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