Native MCP Tool Reference

Product and transport

lispex mcp serve

Native serves stable MCP 2025-11-25 over local stdio using the official rmcp/1.5.0 SDK. It advertises tools only: no resources, prompts, roots, sampling, elicitation, log stream, subscriptions, HTTP transport, or remote endpoint. Startup accepts only three optional, absolute product selections:

lispex mcp serve \
  --topaz-vm /absolute/path/to/topaz-vm \
  --topaz-compiler /absolute/path/to/topaz-compiler \
  --rust-tools /absolute/path/to/rust-tools

--topaz-compiler and --rust-tools must appear together. Products are strictly validated before the server starts. No path can be supplied in a tool request.

Closed tools

Tool	Required input	Optional input	Result
`lispex_reference`	none	`topic`: `forms`, `procedures`, `reader`, `resources`, or `routes`; exact `name`	installed profile and registry answer; unknown names return `known: false`
`lispex_eval`	UTF-8 `source`	one Lispex datum in `input`, bound as `input`	Rust tree values, stdout, warnings, diagnostics, status, resource outcome, and identities
`lispex_diagnostic`	`code` matching `^[EW][0-9]{3}$`	none	exact catalog row and raising condition; unknown codes return `known: false`
`lispex_compare_routes`	`court`: `tree-rust`, `rust-topaz`, or `all-four`; UTF-8 `source`	one Lispex datum in `input`	exact per-route observations, identities, mismatch axes, availability, cleanup, and agreement without answer selection

All request objects are closed. An extra field is invalid rather than ignored. lispex_reference with a name also requires its topic. Evaluation and comparison never accept a file path, route array, executable, endpoint, or capability.

Evaluation result

The structured lispex.mcp-eval-result/v1 includes the current product and profile identity, engine rust-tree, source and optional input SHA-256, canonical values, captured stdout, exact diagnostics and warnings, exit status, resource outcome, metrics, and zero fallback counters.

It also states:

JSON

{
  "source_retained": false,
  "semantic_equivalence_proved": false,
  "vouch_authority": false
}

Reader and runtime failures are ordinary bounded results. Cancellation, wall-clock exhaustion, worker failure, malformed protocol input, and an unsupported protocol version remain visible; none retries another evaluator.

Closed comparison courts

lispex.mcp-route-comparison-result/v1 admits no arbitrary route list:

Court	Exact members	Startup prerequisite
`tree-rust`	built-in tree and Rust VM	none
`rust-topaz`	built-in Rust VM and exact Topaz VM	`--topaz-vm`
`all-four`	tree, Rust VM, Topaz VM, fresh AOT	all three startup options

All members receive the same source, input, Core IR/bytecode derivation, and resource request. A missing prerequisite returns court_available: false with no attempted route. A completed mismatch returns agreement: false; answer_selected and partial_comparison remain false.

all-four creates a private request workspace, builds one fresh AOT product, runs it through the strict product boundary, terminates the complete process group on cancellation or timeout, and removes the workspace before responding. Cleanup failure fails the tool result closed.

Fixed bounds

Boundary	Limit
source	65,536 bytes
input datum	16,384 bytes
evaluation result	1 MiB
comparison result	4 MiB
diagnostics and warnings	256
evaluation wall clock	5,000 ms
comparison wall clock	at most 660,000 ms

The fixed authoring profile also applies the language's transition and control limits. It does not claim an operating-system memory ceiling.

Security and support

The server clears ambient worker configuration and grants no file, clock, random, network, database, or host callback capability. Optional products come only from immutable startup configuration: there is no PATH, environment, checkout, route-lock, catalog, home-directory, or network discovery. Submitted source is not included in results or retained between calls. The service has no network transport.

MCP is Native-only. npm, public WASM, the browser, and the Playground do not expose these tools. MCP output cannot enter Vouch issue, authentication, re-execution evidence, or a gate grant.

Keep going

For a guided setup, use Lispex with an AI Assistant. For the complete Native command table, use Native CLI.