fastmcp.server.transforms.visibility

Visibility transform for marking component visibility state.

Each Visibility instance marks components via internal metadata. Multiple visibility transforms can be stacked - later transforms override earlier ones. Final filtering happens at the Provider level.

Functions

is_enabled ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L271" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

is_enabled(component: FastMCPComponent) -> bool

Check if component is enabled.

Returns True if:

• No visibility mark exists (default is enabled)
• Visibility mark is True

Returns False if visibility mark is False.

Args:

• component: Component to check.

Returns:

• True if component should be enabled/visible to clients.

get_visibility_rules ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L300" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_visibility_rules(context: Context) -> list[dict[str, Any]]

Load visibility rule dicts from session state.

save_visibility_rules ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L305" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

save_visibility_rules(context: Context, rules: list[dict[str, Any]]) -> None

Save visibility rule dicts to session state and send notifications.

Args:

• context: The context to save rules for.
• rules: The visibility rules to save.
• components: Optional hint about which component types are affected. If None, sends notifications for all types (safe default). If provided, only sends notifications for specified types.

create_visibility_transforms ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L332" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

create_visibility_transforms(rules: list[dict[str, Any]]) -> list[Visibility]

Convert rule dicts to Visibility transforms.

get_session_transforms ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L360" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_session_transforms(context: Context) -> list[Visibility]

Get session-specific Visibility transforms from state store.

enable_components ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L372" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

enable_components(context: Context) -> None

Enable components matching criteria for this session only.

Session rules override global transforms. Rules accumulate - each call adds a new rule to the session. Later marks override earlier ones (Visibility transform semantics).

Sends notifications to this session only: ToolListChangedNotification, ResourceListChangedNotification, and PromptListChangedNotification.

Args:

• context: The context for this session.
• names: Component names or URIs to match.
• keys: Component keys to match (e.g., {"tool:my_tool@v1"}).
• version: Component version spec to match.
• tags: Tags to match (component must have at least one).
• components: Component types to match (e.g., {"tool", "prompt"}).
• match_all: If True, matches all components regardless of other criteria.

disable_components ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L426" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

disable_components(context: Context) -> None

Disable components matching criteria for this session only.

Session rules override global transforms. Rules accumulate - each call adds a new rule to the session. Later marks override earlier ones (Visibility transform semantics).

Sends notifications to this session only: ToolListChangedNotification, ResourceListChangedNotification, and PromptListChangedNotification.

Args:

• context: The context for this session.
• names: Component names or URIs to match.
• keys: Component keys to match (e.g., {"tool:my_tool@v1"}).
• version: Component version spec to match.
• tags: Tags to match (component must have at least one).
• components: Component types to match (e.g., {"tool", "prompt"}).
• match_all: If True, matches all components regardless of other criteria.

reset_visibility ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L480" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

reset_visibility(context: Context) -> None

Clear all session visibility rules.

Use this to reset session visibility back to global defaults.

Sends notifications to this session only: ToolListChangedNotification, ResourceListChangedNotification, and PromptListChangedNotification.

Args:

• context: The context for this session.

apply_session_transforms ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L497" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

apply_session_transforms(components: Sequence[ComponentT]) -> Sequence[ComponentT]

Apply session-specific visibility transforms to components.

This helper applies session-level enable/disable rules by marking components with their visibility state. Session transforms override global transforms due to mark-based semantics (later marks win).

Args:

• components: The components to apply session transforms to.

Returns:

• The components with session transforms applied.

Classes

Visibility ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L39" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Sets visibility state on matching components.

Does NOT filter inline - just marks components with visibility state. Later transforms in the chain can override earlier marks. Final filtering happens at the Provider level after all transforms run.

Methods:

list_tools ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L196" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

list_tools(self, tools: Sequence[Tool]) -> Sequence[Tool]

Mark tools by visibility state.

get_tool ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L200" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_tool(self, name: str, call_next: GetToolNext) -> Tool | None

Mark tool if found.

list_resources ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L213" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

list_resources(self, resources: Sequence[Resource]) -> Sequence[Resource]

Mark resources by visibility state.

get_resource ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L217" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_resource(self, uri: str, call_next: GetResourceNext) -> Resource | None

Mark resource if found.

list_resource_templates ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L234" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

list_resource_templates(self, templates: Sequence[ResourceTemplate]) -> Sequence[ResourceTemplate]

Mark resource templates by visibility state.

get_resource_template ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L240" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_resource_template(self, uri: str, call_next: GetResourceTemplateNext) -> ResourceTemplate | None

Mark resource template if found.

list_prompts ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L257" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

list_prompts(self, prompts: Sequence[Prompt]) -> Sequence[Prompt]

Mark prompts by visibility state.

get_prompt ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/transforms/visibility.py#L261" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_prompt(self, name: str, call_next: GetPromptNext) -> Prompt | None

Mark prompt if found.