26.10.1

26.10.1 — explain an unwritable index folder, document --user for Docker on Linux

What changed

• An index folder the server cannot write now fails with the fix, not a raw exception. Before
  creating, adding to, updating or removing from an index, the server checks that the index folder can
  be written. If not, the response (isError: true) reads: "The index folder '…' is not writable by the
  server process. In Docker on Linux the container runs as a non-root user, so a host folder you own is
  read-only to it: add --user "$(id -u):$(id -g)" to docker run, or mount a writable folder at /index and
  set GROUPDOCS_MCP_INDEX_PATH=/index. …" Previously the agent received
  System.UnauthorizedAccessException: Access to the path '/data/.groupdocs-search-index' is denied.
• README: new section Linux: run the container as your user, including the literal-number form
  ("--user", "1000:1000") for MCP client JSON configs, which do not run a shell.
• Unit test for the unwritable-folder path (38 unit tests).

Why

The first CI run of the integration suite against the published 26.10.0 image failed 20 of 31 tests on
ubuntu-latest. The image runs as uid 1654; on a Linux host a bind mount keeps its host owner, so the
runner's temp folder — and any folder a Linux user owns — is read-only inside the container, and the
default index location /data/.groupdocs-search-index cannot be created. Docker Desktop on Windows and
macOS does not enforce bind-mount ownership, which is why local verification passed.

Search is hit harder than the other products because building an index is a write even when the user
only wants to search. The same cause affects every family image that writes into /data (Parser's
extract_images docker tests fail on it); that is tracked in docs/backlog-and-issues.md.

Migration impact

None for callers. Linux Docker users who saw the access-denied error add --user "$(id -u):$(id -g)"
(or the numeric form in JSON configs). Windows and macOS are unaffected.

Full Changelog: 26.10.0...26.10.1

26.10.0

GroupDocs.Search MCP server — first release

What changed

New MCP server GroupDocs.Search.Mcp over GroupDocs.Search for .NET 26.10.0, built on
GroupDocs.Mcp.Core / GroupDocs.Mcp.Local.Storage 26.9.0 and ModelContextProtocol 1.1.0,
targeting net10.0. It is the thirteenth server in the GroupDocs MCP family and the first stateful
one: indexes persist on disk between tool calls and restarts.

Tools:

Tool	What it does
add_to_index	Indexes a file, a folder (recursive) or the whole storage folder; creates the index on demand
search	Ranked matching documents as JSON, with occurrence counts, terms and fields
get_text_fragments	Matching passages with surrounding words, as plain text
update_index	Re-reads changed files, adds new files under indexed folders, drops deleted ones
remove_from_index	Removes an indexed path; files on disk untouched
create_index	Creates or opens a named index; recreate empties it
get_index_info	Existence, counts, indexed paths, version, other indexes, optional supported formats
get_license_status	From Core: licensing mode, engine version, metered consumption

Distribution — Docker-first (OCI):

• Image ghcr.io/groupdocs-search/search-net-mcp:26.10.0 (+ :latest), multi-arch; Docker Hub
  mirror groupdocs/search-net-mcp once the org has the Docker Hub secrets.
• MCP Registry io.github.groupdocs-search/groupdocs-search-mcp, registryType: oci.
• No NuGet package: the packed tool measured 280.9 MiB (2026-10-14) against NuGet.org's
  250 MB limit. The engine DLL alone is 199.6 MiB; the rest is ONNX Runtime and SkiaSharp natives
  that remain after StripMobileAndExoticRuntimes. Stripping further cannot close the gap.

Configuration — the family's five variables plus one:

• GROUPDOCS_MCP_STORAGE_PATH, GROUPDOCS_MCP_OUTPUT_PATH, GROUPDOCS_LICENSE_PATH,
  GROUPDOCS_METERED_PUBLIC_KEY, GROUPDOCS_METERED_PRIVATE_KEY (isSecret).
• GROUPDOCS_MCP_INDEX_PATH — where indexes live. Unset, they go to
  <output or storage>/.groupdocs-search-index; the image leaves it unset on purpose so the index
  persists inside the one /data mount every client config already has.

Design decisions:

• Relative paths only. Document paths are relative to the storage folder and indexes are
  addressed by name; rooted paths and .. escapes are rejected. The server never reads outside
  the folders it was given.
• The index folder is never indexed, even when it sits inside the storage folder — an engine
  DocumentFilter excludes it.
• Failures carry isError: true. Tools return CallToolResult, so engine failures keep the
  family's <Operation> failed for '<target>': … text and set the flag; other products return
  string and come back success-shaped on engine errors.
• Evaluation limits are stated in every response (evaluation field in JSON, a trailing note in
  text): 100 documents per index, 10 documents per search.
• Old indexes are converted. GroupDocs.Search 26.10 cannot open indexes from 22.7–26.8 until
  they are converted; the server converts on first open and keeps the original as
  <name>.pre-26.10-backup.
• Linux image installs libgdiplus libfontconfig1 for the engine's image paths; the
  System.Drawing.EnableUnixSupport switch is kept as the family's inert marker.

Engine behaviour documented in the tool descriptions because an agent would otherwise misread it
(verified on 26.10.0):

• Index.Delete accepts only paths passed to Add. A single file inside an indexed folder cannot
  be removed on its own; remove_from_index says so and lists the indexed paths.
• Unquoted multi-word queries match nothing; phrases need double quotes. search adds a hint
  when that is the likely reason for zero results.
• * is a whole-word wildcard in this DSL; ? is the character wildcard.

Why

Search answers the question the other servers cannot: which of my documents say X, and where?
Agents can read one file at a time; across hundreds of files they need an index. Running it locally
over MCP keeps confidential collections (contracts, HR, email archives) on the user's machine.

Verification

• dotnet test src -c Release: 37/37 pass, including tool tests that drive the real engine in temp
  folders (add, search, phrase, fragments, update after edit, remove, recreate, missing index,
  index-folder exclusion).
• Live stdio session against the published DLL, evaluation mode: tools/list reports 8 tools;
  every tool returns the expected shape; every failure path returns isError: true with the
  prefixed text; get_license_status reports evaluation and engine 26.10.

Migration impact

None — first release.

Full Changelog: https://github.com/groupdocs-search/GroupDocs.Search.Mcp/commits/26.10.0