# Look up employees by e-mail over MCP
URL: https://docs.autociso.io/release-notes/2026-10-mcp-employee-lookup/
Description: The new employee_lookup MCP tool maps e-mail addresses to employee IDs, up to 50 per call, with results by input position and no names or addresses in the response.

## `employee_lookup` (`pii:read`)

**Plans:** every plan.
**Where:** the `/mcp` endpoint, for a token that holds the Owner-granted `pii:read` scope.

`employee_lookup` takes up to 50 e-mail addresses and returns the matching employee IDs, so you can join your own list of people to AutoCISO data without exporting the directory. Pair it with the `employeeId` column of tools such as `access_inventory_list`.

- **Index-based result.** `{ matches: [{ index, employeeId }], unmatchedIndexes, ambiguousIndexes, normalizedCount }`. `index` is the position in the trimmed, lower-cased, de-duplicated list. The response contains no name and no e-mail address.
- **Never a guess.** An address held by more than one employee is listed under `ambiguousIndexes`. Matching is exact; terminated and onboarding employees match too.
- **Whole-call validation.** An empty list, more than 50 distinct addresses or a single malformed address rejects the call with `INVALID_ARGUMENTS`. To look up more than 50 addresses, call again with the next batch.
- **All-or-nothing rate limit.** Every distinct address you submit uses one unit of the token's hourly personal-data allowance, matched or not. If fewer units remain than addresses, the call returns `RATE_LIMITED` and uses nothing.
- **Audited.** Every call is written to your audit trail before the result is returned, with counts, matched employee IDs and masked unmatched addresses; raw addresses are never stored.

The tool needs a `pii:read` token minted after the tool is enabled for your deployment. See [MCP Tool Catalog](https://docs.autociso.io/developers/mcp/tools/) and [Employee identity](https://docs.autociso.io/developers/employee-identity/).