What is Echo?
The one-paragraph version of what Echo is and the problem it solves.
Echo is the Ontology Layer — the system that ingests an organization's scattered knowledge sources and materializes them as one typed graph queryable by humans and agents through a single API and MCP server.
Most retrieval systems build a search index: they tell you which documents mention a thing. Echo builds an ontology: it tells you what the thing *is*, what it is made of, what it depends on, and what breaks when it changes. The distinction matters because an agent that can reason about structure can answer questions a keyword search never will.
What Echo gives an agent
- Typed entities and relations — a module, a table, and a ticket are different kinds of thing with different questions attached. "This code writes to that table" is a different, answerable fact from "this code reads it."
- Cross-source meaning — the same concept referenced in a ticket, a commit message, and a column name resolves to one entity in the graph rather than three strings that happen to look alike.
- Deterministic structure — code structure (modules, symbols, imports, call paths) is derived by parsers, never by a model, and it is reproducible: the same commit produces the same graph every time. Models run on top of that structure and their output is labeled as interpretation.
- Provenance — every fact carries its origin, including whether it was computed deterministically or interpreted by a model. Every returned claim keeps a resolvable ref.
The three planes
Echo models knowledge in three planes — code, work, and data — then connects them into a single ontology. The cross-plane edges are the whole point: anyone can index a repository, but "which service breaks if this column is dropped" is only answerable when the planes share one graph.
One contract, every source
Every source in Echo — code, graph, docs, company docs, work items, commits, PRs, database — flows through the same four operations: discover, search, fetch, and activity. Adding a new source never adds a new endpoint or a new MCP tool. Read the faceted contract for why.
Next: How Echo sees a project.