Plasm OSS documentation¶

Plasm turns APIs into a typed graph (what exists, how it relates, what you can do), maps that graph to HTTP or GraphQL calls, and exposes a compact language agents can learn once—then reuse across catalogs. This site teaches how to run the open-source stack, connect new APIs, or embed the engine in your own systems.

Repository: plasm-core.

Pick your path¶

Path	You want to…	Start here
Run the MCP appliance	Operate `plasm-mcp` (HTTP + Streamable MCP), persistence, and credentials for real teams	Run the MCP appliance
Connect an API	Author `domain.yaml` + `mappings.yaml`, validate, pack plugins	Connect an API → Catalog index
Embed Plasm	Use crates (`plasm-runtime`, `plasm-agent-core`) or subprocess `plasm-mcp` from CI/agents	Embed Plasm

New to the ideas? Read How Plasm fits together, then Start here.

How the pieces stack (one minute)¶

Graph (CGS) — Entities, fields, relations, capabilities: what the domain is (split catalogs: field/param value_ref into values: semantic slots).
Mappings (CML) — Per-capability templates: how calls hit the wire.
Runtime — Executes capabilities, caches rows, handles paging and effects.
Plasm language — Path expressions and programs agents emit against a live DOMAIN table (e# / m# / p#).
Host — plasm-mcp serves MCP tools + HTTP discovery/execute; optional DB-backed MCP policy when configured.

Details and edge cases live in the Reference section and AGENTS.md.

Quick links¶

Need	Page
First commands and “did it work?”	Start here
Mental model + vocabulary	Concepts
Language + heredocs	Language specification
MCP sessions and `intent`	MCP session reuse
Full CLI/env index	CLI & environment

Maintainers¶

Sources under doc-site/docs/ are curated for the public OSS repo; some pages are synced via doc-site/scripts/sync_allowlisted_docs.py — see doc-site/README.md. Examples focus on HTTP and GraphQL catalogs.

OAuth apps blocked? Self-hosted OAuth (especially Google Workspace) is often operationally heavy. Plasm Cloud hosts OAuth provider registration and outbound connection flows for teams that prefer not to own every client ID.