> ## Documentation Index
> Fetch the complete documentation index at: https://docs.enagrams.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Symbol Graph

> Per-workspace index of every top-level function, class, interface, and enum

## What It Is

The symbol graph is a per-workspace pgvector index of the codebase at function/class/interface/enum granularity. Rows live in `symbol_graph_nodes`. Each row carries the symbol's kind, file, line range, neighbour symbols (who calls whom), and a semantic embedding of its signature + leading docstring.

## How It Stays Fresh

A lightweight [`ts-morph`](https://ts-morph.com) extractor runs on every agent write via the `postToolUse` hook. It re-parses only the file that changed and upserts its top-level declarations. The graph is eventually consistent with the repo state within a few hundred milliseconds of an edit.

## What It Powers

| Feature                        | How the graph helps                                                                              |
| ------------------------------ | ------------------------------------------------------------------------------------------------ |
| Symbol-level file reservations | Narrow a lock to `createUser` instead of the whole `src/users.ts`                                |
| Affected-test discovery        | The [test gate](/concepts/test-gate) traces symbol-to-test edges to decide what to run           |
| Living decisions               | Decisions auto-link to the symbols they mention; staleness is detected when those symbols change |
| Negotiations                   | `negotiate_open` targets specific symbols by id or name                                          |
| Knowledge graph UI             | The dashboard visualization renders nodes + call edges                                           |

## Reservations vs Graph

File reservations are a coordination primitive — a lock. The symbol graph is a data structure — a map. They interact via `granularity='symbol'` on a reservation: the lock scopes down to the symbol's line range. The graph decides what counts as a symbol; reservations enforce the lock.

## Language Support

Today: TypeScript and JavaScript (via `ts-morph`). The extractor is pluggable; Python and Go are next on the roadmap.

For languages without an extractor yet, file-level reservations still work — you just lose symbol-level precision.