# 018 — Sequence diagram of events (future idea)

> The README lists this under "Ideas... that can be implemented in the future, but
> not now." Not scoped for current implementation — tracked here so it isn't lost.

## Summary

Let users declare sequence-diagram participants from params or matchers (e.g.
`node_id`), then render a sequence diagram of captured events of interest. No
relation between nodes is modeled — only event sequence/ordering determines the
diagram.

## Scope (sketch, not final)

- Participant declaration referencing an existing param
  ([001](001-param-declarations.md)), e.g. "one participant per distinct value of
  `node_id`".
- Event-of-interest selection, likely reusing FilterBar syntax
  ([005](005-filterbar-pest-parser.md)) to define which log lines become diagram
  events.
- Rendering: a sequence-diagram view (e.g. mermaid `sequenceDiagram`) driven by
  ordered matching events per participant.

## Depends on

- [001 — Param declarations](001-param-declarations.md)
- [005 — FilterBar pest parser](005-filterbar-pest-parser.md) (likely, for
  event-matcher syntax reuse)