* 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)
* Add FastMCPApp — a Provider for composable MCP applications
* Wire Prefab callable resolver via to_json(tool_resolver=) parameter
* Remove inspect.signature compat check, use try/except until prefab 0.10.0
* Address review: fix add_tool registry gaps, normalize auth errors, bump prefab to 0.10.0
* Register global key after _add_component succeeds
* Simplify: extract decorator dispatch, use get_fastmcp_meta, expose get_global_tool
* Remove prek from Marvin workflows
These workflows run Claude to respond to /marvin mentions — linting
the repo is unnecessary and fails without renderer deps installed.
* Return ResolvedTool from callable resolver, add contacts example
The callable resolver now returns ResolvedTool (from prefab_ui) instead of a
plain string, carrying metadata like unwrap_result that the renderer needs to
correctly handle structuredContent envelopes. The unwrap_result flag is derived
from the tool's x-fastmcp-wrap-result output schema marker.
* Bump prefab-ui requirement to >=0.11.0
* Remove stale ty ignore comments now that prefab-ui 0.11 is published
* Add fastmcp dev apps command with browser UI preview
* Improve fastmcp dev apps: dropdown picker, reload flag, process cleanup
- Replace Tabs with Pages+Select for tool picker (Rx-based reactive state)
- Add --reload/--no-reload flag (default: True) to fastmcp dev apps
- Kill entire process group on shutdown so port 8000 is freed properly
- Suppress uvicorn websockets deprecation warning (websockets-sansio)
- Bump prefab-ui to >=0.11.1 (fixes get_renderer_head bug in 0.11.0)
- Add farewell tool to greet_server example for multi-tool testing
* Add docs for fastmcp dev apps command
* Fix orphaned server on startup failure, guard Unix-only signal handling
* Show tool title in picker, remove editable prefab source
* Bump prefab-ui to >=0.11.2
* Fail fast when prefab-ui is not installed
* Add apps/development docs, link from prefab and sidebar
* Fix optional field defaults, fail with non-zero on startup timeout
Replace PyAI Conf banner with Prefect Horizon banner. Add mobile
media query to reduce banner font size and padding so text stays
on one line at narrow viewports.
* Decompose CodeMode into composable discovery tools
CodeMode now owns only the execute sandbox. Discovery tools (search,
get_schema, etc.) are composable via the discovery_tools parameter.
Each is a Callable[[GetToolCatalog], Tool] factory.
Ships SearchTool (lightweight name+description results) and SchemaTool
(brief markdown or full JSON schemas by tool name) as built-in defaults.
* Rename to Search/GetSchemas/Tags, add tag filtering, fix bugs
- Rename SearchTool→Search, SchemaTool→GetSchemas, Categories→Tags
- Add tags parameter to Search for LLM-side tag filtering
- Add Tags discovery tool for browsing tools by tag
- Fix shared singleton default factories (now per-instance)
- Fix get_schema full mode returning invalid JSON on partial matches
- Fix "untagged" filter inconsistency between Tags and Search
- Split serialization tests to comply with loq line limit
- Rewrite docs for conceptual clarity
* Add three-tier detail levels, remove default_arguments, rename Tags→GetTags, rewrite docs
* Clean up __all__ exports, return valid JSON for empty full-detail results
Adds the PropelAuthProvider which delegates to the IntrospectionTokenVerifier
and optionally does an additional resource check.
Adds an example server and client which makes an authenticated request
and gets information from the token.
Updates the documentation (but only for v3 as this isn't in v2).
* Add MultiAuth for composing multiple token verification sources
🤖 Generated with Claude Code
https://claude.ai/code/session_01WwKYDCqjM2FqYwY5ZNVvjb
* Fix ruff lint/format in MultiAuth tests
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https://claude.ai/code/session_01WwKYDCqjM2FqYwY5ZNVvjb
* Fix MultiAuth well-known route delegation and empty scopes handling
🤖 Generated with Claude Code
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* Harden MultiAuth: exception resilience, mcp_path propagation, test coverage
- verify_token now catches exceptions from individual sources and
continues to the next, so one broken verifier can't take down the
whole chain
- set_mcp_path propagates to verifiers, not just the server
- Fix jwks_url→jwks_uri typo in class docstring
- Add tests for raising verifiers, valid-token HTTP acceptance,
and set_mcp_path propagation
* Clean up MultiAuth: precompute sources, deduplicate test helpers
* Fix version badges to 3.1.0
---------
Co-authored-by: Claude <noreply@anthropic.com>
* Add prefab auto-wiring for MCP Apps (#3119)
Tools that return prefab types (UIResponse, Component) automatically get
wired to the shared prefab renderer resource. Works via app=True,
return type inference, or both.
* Prefab compatibility updates
* Use published prefab-ui >=0.6.0, remove local source override
* Migrate UIResponse to PrefabApp for Prefab UI integration
PrefabApp is a pure data object with to_json(), html(), and csp()
methods. Tools can return PrefabApp, bare Components, or
ToolResult with structured_content for custom LLM fallback text.
* Add Prefab UI apps documentation
* Add mini apps and full apps documentation pages
Mini apps covers the common single-screen patterns: charts (bar, line,
area, pie), data tables with sorting/search/pagination, forms (manual
and Pydantic-generated), status displays, conditional content, and
layout composition with tabs and accordions.
Full apps covers multi-page applications using Pages/Page components,
shared state across pages, and using ToolCall with result_key for
server-driven state updates.
* Reframe apps docs around motivation, add generative UIs page
The docs now lead with the problem — MCP tools stuff data into the LLM
context window, and building HTML/JS/CSS frontends is a non-starter for
Python developers — before introducing Prefab as the solution. Mini apps
are framed as the primary use case: focused, single-purpose UIs that
present data visually and collect structured input.
New generative UIs page covers the concept of LLMs producing component
JSON directly, enabling adaptive dashboards, tailored forms, and
exploratory workflows.
* Tag Prefab docs pages as SOON instead of NEW
* Rename Low-Level API to Custom HTML Apps
The page is about using the MCP Apps extension directly, not a FastMCP
or Prefab internal API. Reframed to make clear this is the open MCP
protocol with FastMCP providing convenience wrappers.
* Tighten apps docs and widen content area
Strip editorial motivation from all app doc pages — let code examples
do the talking. Add content-area max-width override (44rem) to style.css.
* Restructure apps docs, fix code issues
Rename Prefab UI → Prefab Apps, mini-apps → patterns, remove
generative-uis and full-apps pages. Rewrite prefab page to lead with
what users do (declare a UI, return it) before explaining internals.
Patterns page now has fully self-contained copy-pasteable examples with
explicit imports and links to prefab docs. Forms show the two-tool
pattern (form + handler). Add patterns_server.py example.
Code fixes: move get_args to module-level import, remove dead
AuthCheckCallable type alias, fix ToolCall→CallTool in all docs.
* Remove unused ToolResult import from chart_server
* Handle composite Prefab types in type inference and schema suppression
_has_prefab_return_type and the output schema suppression logic only
checked bare classes, missing unions (Column | None) and Annotated
wrappers (Annotated[PrefabApp | None, ...]). Recurse through Union,
types.UnionType, and Annotated to detect Prefab types in composite
annotations.
* code mode
* update uv.lock for monty optional dep
🤖 Generated with Claude Code
* retry CI
* Address PR review comments on CodeMode transform
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Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* Fix ty unresolved-attribute error on search_helper
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Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* more idiomacy
* harden
* fix docs
* harden
* fix red CI
* Refactor CodeMode to use CatalogTransform base class
Removes the duplicate ContextVar bypass pattern in favor of the shared
CatalogTransform machinery. Also fixes a pre-existing bug where
`from __future__ import annotations` caused NameError for Annotated
in nested function scopes at runtime.
* Remove redundant _get_visible_tools wrapper in CodeMode
* Rewrite CodeMode docs with proper motivation and structure
* Fix type narrowing in collision test
* Stop unwrapping tool results in CodeMode's call_tool
call_tool() inside execute blocks now returns structured content as-is,
preserving the {"result": value} wrapping. This means the output schema
shown in search results accurately describes what call_tool() returns,
so LLMs can trust the schema when writing code.
Also adds examples/code_mode/ with a server and narrated client demo.
* Simplify call_tool return type: dict | str
* Fix example client to unwrap structured results
* Let server resolve tool versions instead of pinning first match
* Rewrite CodeMode docs to match current behavior
* Rename optional extra from monty to code-mode
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
* feat: Add search transforms for tool discovery
RegexSearchTransform and BM25SearchTransform collapse large tool
catalogs into a search interface so LLMs discover tools on demand
instead of receiving the full listing.
* chore: Update SDK documentation
* fix: call_tool recursion guard, atomic BM25 rebuild, hash includes descriptions
* Extract CatalogTransform base class for catalog-aware transforms
Transforms that replace list_tools() with synthetic components (like
search) need to read the real catalog at call time without triggering
their own replacement logic. CatalogTransform handles the re-entrant
bypass via per-instance ContextVar, exposing transform_tools() as the
subclass hook and get_tool_catalog() for catalog access.
* Add search transform examples for regex and BM25
* Add README for search transform examples
* Polish search example clients with rich output
* Remove hardcoded tool counts from search example subtitles
* Clarify that review bot feedback should be evaluated on its merits
* Expand search transform docs with proper hierarchy
---------
Co-authored-by: marvin-context-protocol[bot] <225465937+marvin-context-protocol[bot]@users.noreply.github.com>
* Add upgrade guides for users coming from the MCP SDK
* Fix incorrect Image import path in LLM migration prompt
* Align LLM prompts with prose across all three upgrade guides
* Move upgrade guides under getting-started/upgrading, add install section and --upgrade flag
* Update repository references from jlowin/fastmcp to prefecthq/fastmcp
* Retrigger CI after repo transfer
* chore: Update SDK documentation
* Only run deep triage on bug issues for jlowin
---------
Co-authored-by: marvin-context-protocol[bot] <225465937+marvin-context-protocol[bot]@users.noreply.github.com>
* Reorganize docs navigation and add Apps documentation
Collapse Providers, Transforms, and Deployment under Servers. Add Apps
section with overview and low-level API pages. Add card images to welcome
page and README. Add NEW tags to recent features.
* Fix missing imports in Apps low-level API code examples
