Struct McpExtension 

pub struct McpExtension { /* private fields */ }

MCP Extension that provides MCP server management.

Provides:

• mcp proxy tool (gateway to all configured servers)
• Direct tools for servers with directTools enabled (optional)
• Tool renderers for MCP tool calls/results

Implementations

impl McpExtension

pub fn new(config: McpConfig) -> Self

Create a new MCP extension from a loaded config.

pub fn from_cwd(cwd: &Path) -> Self

Create from config loaded from disk at the given working directory.

pub async fn restore_cache(&self)

Restore cached tool metadata from the on-disk cache. Should be called once at startup to prime the cache without connecting.

pub async fn bootstrap_direct_tools(&self)

Bootstrap direct tools — checks which servers have directTools configured but no cached metadata yet, and logs a hint. Does NOT block startup on network connections. The first connection (via mcp({{ connect: ... }}) or mcp({{ server: ... }})) populates the cache; on subsequent startups direct tools are available automatically.

Trait Implementations

impl Extension for McpExtension

fn name(&self) -> Cow<'static, str>

fn tools(&self) -> Vec<ToolDefinition>

Tools this extension provides (LLM-callable), each with its own prompt metadata.

fn commands(&self) -> Vec<SlashCommand>

Slash commands this extension provides (e.g. /quit, /model). Built-in commands and extension commands use the same interface.

fn skills(&self) -> SkillSet

Skills this extension provides (AgentSkills-compatible). Merged into the session’s skill set for /skill:name expansion and system prompt.

fn before_compact( &self, _first_kept_entry_id: &str, _tokens_before: u64, _reason: &str, _cancel: &Cancel, ) -> Option<BeforeCompactResult>

Called before compaction runs (matching pi’s session_before_compact). Return Some(BeforeCompactResult { cancel: true, .. }) to cancel compaction. Return Some(BeforeCompactResult { cancel: false, summary: Some(...), .. }) to provide a custom summary instead of calling the provider. Return None to let the default compaction proceed.

fn after_compact( &self, _summary: &str, _first_kept_entry_id: &str, _tokens_before: u64, _estimated_tokens_after: u64, _from_hook: bool, _reason: &str, _cancel: &Cancel, )

Called after compaction completes (matching pi’s session_compact).