# elicit_server
> **Compositions that no single crate can hold**
The [elicitation](https://docs.rs/elicitation) library teaches agents to
think in types — constructing valid domain values through typed, contract-carrying
operations rather than filling in JSON forms. Each shadow crate (`elicit_reqwest`,
`elicit_url`, `elicit_serde_json`, …) exposes one slice of that language.
`elicit_server` is where those slices compose into something greater.
## What makes cross-crate composition special
Individual crates prove local invariants. Composition proves end-to-end
contracts that span multiple domains. The typestate proof chains here are not
validation — they are compiler-enforced proofs that an agent cannot skip a step:
**SecureFetchPlugin** (`elicit_url` + `elicit_reqwest`)
```text
UnvalidatedUrl → UrlParsed → HttpsRequired → RequestCompleted ∧ StatusSuccess
```
An agent cannot reach `RequestCompleted` without first passing through
`HttpsRequired`. The HTTPS contract is not a runtime check — it is structurally
unreachable to bypass.
**FetchAndParsePlugin** (`elicit_reqwest` + `elicit_serde_json`)
```text
RequestCompleted → JsonParsed → PointerResolved
```
The JSON pointer is only resolvable against a value that was provably fetched and
parsed. The agent builds the proof chain step by step.
## Code recovery (`emit` feature)
When an agent has assembled a verified workflow interactively, it can ask
`EmitBinaryPlugin` to recover that session as a standalone, compilable Rust binary
— with all typestate ceremony, proof tokens, and contract types intact.
```text
Agent builds workflow → calls emit_binary → gets a main.rs → cargo build → ships it
```
The output is not a script. It is idiomatic Rust that compiles and runs without
the MCP server. The agent's exploration becomes production code.
## Plugins
| `SecureFetchPlugin` | `secure_fetch`, `validated_api_call` | default |
| `FetchAndParsePlugin` | `fetch_and_extract`, `fetch_and_validate` | default |
| `EmitBinaryPlugin` | `emit_binary` | `emit` |
## Usage
```rust,no_run
use elicitation::PluginRegistry;
use elicit_server::{SecureFetchPlugin, FetchAndParsePlugin};
#[tokio::main]
async fn main() {
let registry = PluginRegistry::new()
.register("secure_fetch", SecureFetchPlugin)
.register("fetch_and_parse", FetchAndParsePlugin);
// registry.serve(rmcp::transport::stdio()).await.unwrap();
}
```