Object-typed query parameters with explode=true (the default) were
passed as raw Python dicts to httpx, which called str() on them —
producing Python repr syntax (single quotes, capitalized booleans)
instead of proper query parameter serialization.
Per the OpenAPI specification, style=form with explode=true on objects
expands each property as a separate query parameter (e.g.
?myAttribute=true). This change handles dict values in both the
explode=true and explode=false branches of _serialize_query_params,
using the existing _query_scalar_to_str helper for correct boolean
formatting.
Fixes#2857
Hosts (Goose, MCP Jam) don't forward _meta on callServerTool, which
broke app tool routing entirely. Encode the app identity in the tool
name on the wire instead: the resolver writes "AppName___tool_name",
and the server parses it to route via get_app_tool.
* fix: recover StdioTransport after subprocess exits
🤖 Generated with Claude Code
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix: improve Windows reliability for stdio crash recovery
🤖 Generated with Claude Code
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix: filesystem provider import machinery
- Temporary sys.path entries (both package and non-package mode) now removed
immediately after exec_module via try/finally, eliminating permanent process-wide pollution
- Non-package files use bare stem as sys.modules key only if unclaimed; falls back
to private hash-based key to prevent stdlib shadowing (e.g. json.py clobbering json)
- Reload of private-key modules uses spec.loader.exec_module directly instead of
importlib.reload, which cannot find files by their private synthetic name
- _find_package_root gains stop_at parameter; discover_and_import passes provider_root
to prevent package root discovery from escaping above the provider boundary
Closes#3625 (issues 2, 3, 6)
🤖 Generated with Claude Code
* fix: use contextlib.suppress for SIM105 linting
🤖 Generated with Claude Code
* test: add import machinery regression tests
🤖 Generated with Claude Code
* fix: resolve provider_root before path comparison; improve tests
- Resolve provider_root in import_module_from_file so the stop_at boundary
in _find_package_root works correctly when provider_root is a relative path
(e.g. FileSystemProvider(Path("./mcp"))) — previously the resolved file_path
and unresolved stop_at.parent would never compare equal
- Fix test_stdlib_not_shadowed: use unconditional finally to restore sys.modules["json"]
- Strengthen test_same_stem_files: assert mod_a is not mod_b and that sys.modules["helpers"]
was not clobbered by the second import
- Replace direct _find_package_root unit test with an integration test through
import_module_from_file(provider_root=...) that also verifies the module name
and that tmp_path is not added to sys.path
🤖 Generated with Claude Code
Adds Provider.get_app_tool(app_name, tool_name) — a dedicated method for
finding app-visible tools by their original name, bypassing transforms.
AggregateProvider queries children, WrappedProvider delegates to inner,
FastMCPProvider delegates to nested server. The default implementation
checks _get_tool and matches meta.fastmcp.app.
This replaces the process-level _APP_TOOLS registry. Tool routing now
works through the provider tree, which exists in every process — no
shared state needed for horizontal scaling.
* Transparently refresh upstream token in OAuthProxy.load_access_token()
When upstream token validation fails during load_access_token, attempt
to refresh using the stored refresh token before returning None. This
prevents premature 401s that force clients into expensive full re-auth
flows when the upstream token expires.
Co-authored-by: Claude <noreply@anthropic.com>
* Gate transparent refresh on token expiry, add advisory lock
Only attempt upstream refresh when the token is actually expired, not
on any validation failure (scope mismatch, revocation, etc.). Add
per-token advisory lock to prevent concurrent async tasks from racing
to refresh the same upstream token.
* Re-check expiry inside lock, reload from storage after refresh failure
---------
Co-authored-by: Claude <noreply@anthropic.com>
* Replace UUID global keys with (app_name, tool_name) registry
Collapses three module-level registries (_APP_TOOL_REGISTRY,
_FN_TO_GLOBAL_KEY, _NAME_TO_GLOBAL_KEY) into one: _APP_TOOLS keyed by
(app_name, tool_name). Removes UUID generation, global key stamping in
metadata, and the complex resolver that mapped callables and strings
through multiple fallback paths.
The server now reads _meta.fastmcp.app from the MCP request (set by the
Prefab renderer) and routes directly to the named app's tool. Two apps
with the same tool name are disambiguated by app name, not by UUID.
The resolver is simplified to pass-through: CallTool("save") serializes
as "save", and the server resolves it at call time using the app context.
* Read app name from _meta.prefab.app to match Prefab renderer
* Inject _meta.fastmcp.app into @app.ui() structured content
The @app.ui() decorator stores the FastMCPApp name in the tool's metadata.
When the tool result is serialized, _prefab_to_json injects it as
_meta.fastmcp.app in the structured content. The Prefab renderer reads
this on init and echoes it back as _meta.fastmcp.app on every
callServerTool call, completing the routing loop.
* feat: Add encoding parameter to FileResource
- Add optional encoding field (str | None, default None) to FileResource.
- Pass encoding through to read_text() for cross-platform text file reading.
- Preserve backward compatibility by defaulting to system encoding.
* test: Add tests for FileResource encoding parameter
- Test UTF-8 reading with explicit encoding for non-ASCII content.
- Test backward compatibility when no encoding is specified.
- Test that encoding is ignored for binary file reads.
- Test Latin-1 reading with matching encoding.
* docs: Document FileResource encoding parameter
- Add encoding="utf-8" to FileResource example in resource classes guide.
- Update FileResource description to mention encoding support.
* feat: Change FileResource encoding default from None to utf-8
- Default to utf-8 instead of system encoding to prevent cross-platform footgun.
- Update field description to reflect new default.
- Update test to verify default encoding is utf-8 with non-ASCII content.
- Remove redundant encoding="utf-8" from docs example since it is now the default.
* Comprehensive MCP Apps docs, string CallTool resolution, bump prefab-ui >=0.13.0
Rewrites the apps documentation as a learning journey: overview → Prefab apps
→ FastMCPApp → patterns → dev tools → custom HTML. Adds a new FastMCPApp page
covering composable apps with @app.tool()/@app.ui(), CallTool, forms, actions,
and composition. Teaches Rx() and set_initial_state() as the primary state API.
Adds string-based CallTool resolution so CallTool("save_contact") resolves to
the tool's global key, matching callable ref behavior. Requires prefab-ui 0.13.0
which passes strings through the tool resolver.
* Detect ambiguous string CallTool resolution across apps
* Simplify string name registry to plain dict (last-write-wins)
* feat: add TokenCache utility and caching to GitHubTokenVerifier
Extract the caching machinery from IntrospectionTokenVerifier into a
shared TokenCache class in fastmcp.utilities.token_cache, then wire
it into both IntrospectionTokenVerifier and GitHubTokenVerifier.
* Remove dead constant, validate negative cache params
* Fix overwrite eviction bug, skip cache on scope lookup failure
* feat: support ImageContent and AudioContent in sampling handlers
Co-authored-by: Claude <noreply@anthropic.com>
* Validate image MIME types, fix silent drop in assistant list messages
* Reject image/audio in assistant messages with tool_calls
* Reject ImageContent in assistant messages for Anthropic
---------
Co-authored-by: Claude <noreply@anthropic.com>
* fix: suppress output schema for ToolResult subclass annotations
* use issubclass_safe/is_class_member_of_type for ToolResult subclass checks
* use parsed_fn.return_type for ToolResult check in transform fallback
* pin pydantic-monty to 0.0.8
* rename tool/prompt/resource base modules to avoid decorator name shadow
* add sys.modules shims for old submodule import paths
* preserve original module paths in deprecation warnings
* clarify when sys.modules shims can be removed
* fix: enforce auth/visibility in ResourcesAsTools and PromptsAsTools for non-FastMCP providers
🤖 Co-authored-by: Claude <noreply@anthropic.com>
* fix: honor stdio auth bypass and correct transform ordering in provider wrappers
Co-authored-by: Claude <noreply@anthropic.com>
* fix: move context/dependencies imports into function to break circular import
* fix: route ResourcesAsTools/PromptsAsTools through ctx.fastmcp
Instead of manually reimplementing auth, visibility, and session
transforms in the transform layer, tool functions now call
ctx.fastmcp.read_resource() / ctx.fastmcp.render_prompt() which
routes through the server's full middleware chain. This matches
the pattern CodeMode uses with ctx.fastmcp.call_tool().
The isinstance(provider, FastMCP) branching is removed entirely.
* feat: add _scope parameter for provider-scoped listing
AggregateProvider can now filter which child providers to query when
listing components. ResourcesAsTools and PromptsAsTools use this to
scope listings to their configured provider while still routing
through ctx.fastmcp for full middleware coverage.
The scope matching walks wrapped providers, so a
WrappedProvider(Namespace, inner=MyProvider) matches if MyProvider
is in the scope list.
* test: add coverage for ResourcesAsTools scoped to a sub-server
* fix: delegate to super() when _scope is None, add AggregateProvider to scope matching
* simplify: remove _scope machinery, route everything through ctx.fastmcp
Reverts the _scope parameter from Provider/AggregateProvider/Server.
ResourcesAsTools and PromptsAsTools now simply route through
ctx.fastmcp for all operations. Apply to a FastMCP server instance
for proper auth/visibility/middleware coverage.
Tests rewritten to use FastMCP server directly instead of raw providers.
* warn when ResourcesAsTools/PromptsAsTools is applied to a non-FastMCP provider
* docs: explain that ResourcesAsTools/PromptsAsTools should wrap a FastMCP server
* raise TypeError instead of warning when applied to non-FastMCP provider
---------
Co-authored-by: Claude <noreply@anthropic.com>
Keycloak returns refresh_expires_in=0 for offline tokens (offline_access scope),
meaning "no fixed time-based expiry". The truthiness check on this value caused
the proxy to skip issuing a PROXY_RT, forcing browser re-auth every hour.
Closes#3509🤖 Generated with Claude Code
Co-authored-by: Marvin Context Protocol <41898282+Marvin Context Protocol@users.noreply.github.com>
Co-authored-by: Jeremiah Lowin <jlowin@users.noreply.github.com>
* fix: stop passing follow_redirects to httpx_client_factory
Remove the `follow_redirects=True` kwarg that was being forced onto
custom httpx_client_factory calls with a type: ignore suppression.
The McpHttpClientFactory protocol does not include follow_redirects,
so this was a protocol violation. httpx already strips Authorization
headers on cross-origin redirects via its _redirect_headers mechanism.
🤖 Co-authored-by: Claude <noreply@anthropic.com>
* fix: restore follow_redirects=True for custom httpx client factories
httpx already strips Authorization headers on cross-origin redirects,
so follow_redirects is safe to keep. Removing it broke redirect
handling for users providing custom factories.
* fix: remove vacuous test that never invoked connect_session
The test asserted on received_kwargs but never called connect_session,
so the factory was never invoked and the assertion was a no-op.
* fix: use AsyncClient with transport= instead of monkey-patching _transport
* fix: prevent path traversal in skill download via malicious skill names
Co-authored-by: Claude <noreply@anthropic.com>
* fix: resolve skill_dir once and use consistently to prevent overwrite bypass
---------
Co-authored-by: Claude <noreply@anthropic.com>
* feat: make upstream_client_secret optional in OAuthProxy
Extract _create_upstream_oauth_client() factory method for subclass
override. Cookie signing falls back to JWT key material when no secret.
* fix: include client_id in revocation requests for public clients
* fix: use factory method for revocation auth
* fix: URL-encode path params in OpenAPI provider to prevent SSRF/path traversal
Co-authored-by: Claude <noreply@anthropic.com>
* Exempt too-long from core-category requirement in triage
* fix: also encode dots in path params to prevent bare .. traversal
* fix: only encode .. (not all dots) to preserve valid dotted values
* fix: encode all dots in path params to prevent single-dot normalization
* fix: check decoded path stays within prefix in double-encoding test
---------
Co-authored-by: Claude <noreply@anthropic.com>
