---
id: "0034"
date: 2026-07-13
status: Accepted
supersedes:
superseded-by:
affected-paths: [plugins/os-backlog/lib/backlog/project_index.rb, plugins/os-backlog/bin/os-backlog, plugins/os-backlog/hooks/session_start.py, plugins/os-backlog/skills/route/references/cross-project-filing.md]
affected-components: [os-backlog]
---

# 0034 — Cross-project filing: file-dont-fix with a derived global project index

## Context

Work discovered mid-session often belongs to a different project than the one being worked on (issue #27). Editing the other project from the wrong session loses context and bypasses its tracker; but filing requires knowing which tracker that project uses, which until now lived only in its per-project .cc-os/config (ADR-0027).

## Decision

File-don't-fix: a session never edits another project — it files an issue/card on that project's own tracker. To make the target tracker discoverable, os-backlog maintains a derived global project index at ~/.cc-os/projects.json, upserted as a side effect of every successful config-write and queried via `os-backlog projects`. This is deliberately GLOBAL state, distinct from the per-project .cc-os/ state of ADR-0027; it is derived and rebuildable (re-running route/config-write regenerates rows). Filed items carry a Discoverer metadata block (filing repo/path, Claude Code session id, date, one-line motivation); the session id comes from the SessionStart hook stdin JSON or the transcript filename and is NEVER fabricated — write "session id unavailable" if unknown. Routing inside the target project still follows its own boundary rule (ADR-0033). Filing mechanics live in plugins/os-backlog/skills/route/references/cross-project-filing.md, not restated here.

## Consequences

One compact CROSS-PROJECT rule line added to the os-backlog SessionStart note. Index rows only exist for projects that have run config-write; unrouted projects are reported, not guessed. Related: issue #27, ADR-0027, ADR-0029, ADR-0033.

## Alternatives rejected


