---
phase: 07-user-access-audit
plan: 03
subsystem: graph-user-search-service
tags: [graph-api, user-search, people-picker, services]
dependency_graph:
  requires: [07-01]
  provides: [GraphUserSearchService]
  affects: [07-04, 07-05]
tech_stack:
  added: []
  patterns: [Microsoft Graph SDK, OData filter, startsWith, ConsistencyLevel=eventual]
key_files:
  created:
    - SharepointToolbox/Services/GraphUserSearchService.cs
  modified: []
decisions:
  - "Minimum 2-character query guard prevents overly broad Graph API requests"
  - "Single-quote escaping in OData filter prevents injection (replace ' with '')"
  - "ConsistencyLevel=eventual + Count=true both required for startsWith on directory objects"
metrics:
  duration_minutes: 2
  completed_date: "2026-04-07"
  tasks_completed: 1
  files_created: 1
  files_modified: 0
---

# Phase 7 Plan 03: GraphUserSearchService Implementation Summary

**One-liner:** GraphUserSearchService implements IGraphUserSearchService using GraphClientFactory, querying Graph /users with startsWith OData filter on displayName, mail, and UPN for people-picker autocomplete.

## What Was Built

**GraphUserSearchService.cs** — Concrete implementation of IGraphUserSearchService. Queries the Microsoft Graph `/users` endpoint using OData `startsWith` filter across three fields (displayName, mail, userPrincipalName). Sets the required `ConsistencyLevel: eventual` header and `$count=true` parameter mandatory for advanced directory filters. Returns up to `maxResults` (default 10) `GraphUserResult` records ordered by displayName. Guards against queries shorter than 2 characters to prevent broad, wasteful API calls.

## Tasks

| # | Task | Status | Commit |
|---|------|--------|--------|
| 1 | Implement GraphUserSearchService | Done | 026b829 |

## Decisions Made

1. **2-character minimum guard** — Queries of 0 or 1 character return an empty list immediately without calling Graph. This prevents overly broad results and unnecessary API calls while the user is still typing.

2. **OData single-quote escaping** — Query strings replace `'` with `''` before embedding in the OData filter. This prevents OData injection if user input contains apostrophes (e.g., "O'Brien").

3. **ConsistencyLevel=eventual + Count=true** — Microsoft Graph requires both headers when using `startsWith` on directory objects. Omitting either causes a 400 Bad Request. Both are set together in the request configuration.

## Deviations from Plan

None — plan executed exactly as written.

## Verification

- `dotnet build SharepointToolbox/SharepointToolbox.csproj` — 0 errors, 0 warnings
- GraphUserSearchService.cs implements IGraphUserSearchService confirmed
- Uses GraphClientFactory.CreateClientAsync for auth (not raw HTTP)
- Empty/short query guard (length < 2) returns Array.Empty<GraphUserResult>()
- Filter covers displayName, mail, and userPrincipalName with startsWith

## Self-Check: PASSED

Files confirmed present:
- FOUND: SharepointToolbox/Services/GraphUserSearchService.cs

Commits confirmed:
- FOUND: 026b829
