Module gateway 

MCP Tool-Catalog Gateway (#210).

Turns lean-ctx into a gateway in front of any number of downstream MCP servers. Instead of injecting every downstream tool schema into the system prompt (the “more tools → less adoption” tax), the gateway:

1. aggregates the downstream catalogs (catalog) behind a TTL cache,
2. ranks them per query with BM25 (router) into a top-N ChoiceCard shortlist, and
3. proxies the actual call to the owning server (client).

Net effect: unlimited downstream tools at (roughly) constant context cost. Fully no-op until gateway.enabled = true.

Re-exports

pub use catalog::Catalog;

pub use config::GatewayConfig;

pub use config::GatewayServer;

pub use config::ResolvedTransport;

pub use config::TransportKind;

pub use router::ScoredTool;

Modules

adapters

L4 typed adapters (deeper addon integration, #1096–#1101).

catalog

Aggregated downstream tool catalog (#210) with a TTL cache.

client

Downstream MCP client (#210).

config

Gateway configuration (#210): downstream MCP servers + routing knobs.

pool

Persistent downstream MCP session pool (#1078).

postprocess

Gateway output post-processor (deeper addon integration).

router

Query router (#210): rank the aggregated catalog against a query.

Structs

FindOutcome

Outcome of a find query: the ranked shortlist plus catalog context.

Functions

find

Rank the downstream catalog against query and return the top-N shortlist.

proxy

Proxy a server::tool call to its owning downstream server.

render_cards

Render a FindOutcome as compact ChoiceCards for the model.

servers_overview

Per-server tool counts (for ctx_tools list).