context-update

name	context-update
description	Refresh .abstract.md (L0) and .overview.md (L1) across all subsystems. Diff mode (default) updates only subsystems modified since the last index; regeneration mode rewrites everything. Invoke with /context-update when indexes may be stale, before running the large task planning protocol, or after significant refactors.
context	fork
allowed-tools	["Bash","Read","Write","Edit","Glob","Grep","Task"]

context-update

Keeps .overview.md (L1) and .abstract.md (L0) accurate across all subsystems. These files are the primary orientation layer for agents — the planning and execution protocol depends on them being complete and current.

When to use

Invoke with /context-update when:

• About to run the large task planning and execution protocol
• After a significant refactor, file rename, or new subsystem added
• Indexes haven't been updated in a while and you suspect drift
• A domain agent reported a gap between the index and reality

Inputs

• Mode (optional): diff (default) or regen
  • diff — update only subsystems modified since the last index write
  • regen — full scrape of every subsystem; use when drift is extensive or after large-scale restructuring

Steps

1. Discover subsystems

Find every subsystem that owns a .overview.md:

find . -name ".overview.md" -not -path "./.git/*"

Each directory containing one is a subsystem. If none exist, all subsystems are new — treat every subsystem as requiring full regeneration regardless of mode.

2. Triage dirty subsystems (diff mode only)

For each subsystem directory, find source files modified more recently than its .overview.md:

find <subsystem>/ -newer <subsystem>/.overview.md \
  -type f -not -path "*/.git/*" -not -name "*.md"

If the dirty file list is empty, skip this subsystem — nothing to update. If .overview.md does not exist for a subsystem, treat it as fully dirty (regenerate that subsystem).

In regen mode, skip triage — all subsystems are dirty.

3. Print dry-run summary before writing

Before spawning any agents, output a table:

Subsystem       Mode    Dirty files
──────────────  ──────  ───────────
<subsystem-a>   diff    4
<subsystem-b>   diff    0 (skip)
<subsystem-c>   regen   all

Ask the user to confirm before proceeding if the total dirty file count is large (>20 files or >3 subsystems in regen mode).

4. Spawn parallel Sonnet agents per dirty subsystem

For each subsystem that needs updating, spawn one Sonnet agent (via Task, model: sonnet). Pass it:

• The subsystem path
• The mode (diff or regen)
• The dirty file list (diff mode) or instruction to read all files (regen)
• The current contents of .overview.md (diff mode — for patching)

Each agent's job:

1. AST skeleton extraction (optional, supported languages only): For Python, JS/TS, Rust, Go, Java, C/C++, extract signatures using grep-based patterns before reading full files. This reduces tokens consumed:

   • Python: grep -n "^def \|^class \|^async def "
   • JS/TS: grep -n "^export \|^function \|^class \|^const \|^interface \|^type "
   • Rust: grep -n "^pub fn \|^pub struct \|^pub enum \|^pub trait \|^fn "
   • Go: grep -n "^func \|^type \|^var \|^const "
   • Java: grep -n "public \|private \|protected \|class \|interface \|enum "
   • C/C++: grep -n "^[a-zA-Z].*(.*)" Fallback to full-file read for unsupported languages or when signatures are insufficient.

2. Produce .overview.md (L1) — merged format:

   • Overview paragraph: what this subsystem as a whole does
   • Component table (one row per file or directory):

     Path	Type	Purpose	Exports	Deps

   • Endpoints (if applicable)
   • Dev workflow (if applicable) Token budget: ~2 000 tokens.

3. Produce .abstract.md (L0) — derived from L1:

   • One line per component: path + one-sentence purpose
   • Table format: | Path | Purpose | Token budget: ~100 tokens.

All agents write directly to their own subsystem's .overview.md and .abstract.md — no shared output files, no collision risk.

5. Update root context files

After all subsystem agents complete, spawn a single Sonnet consolidation agent to produce the root .overview.md and .abstract.md. It reads all updated subsystem .overview.md files and produces:

• Root .overview.md — project-wide L1: what this project is, repository map (all subsystems), subagent quick-reference, service endpoints, stack at a glance, dev workflow, storage, non-negotiables. Target: under 150 lines.
• Root .abstract.md — project-wide L0: one line per subsystem, derived from the repository map. Target: under 20 lines.

6. Report

Print a completion summary:

• Subsystems updated and file counts
• Whether root context files were rewritten
• Any subsystems skipped (no dirty files)
• Any gaps or ambiguities the agents flagged during scraping

Expected output

• .overview.md and .abstract.md updated in every dirty subsystem
• Root .overview.md and .abstract.md rewritten to reflect current state
• A brief summary printed confirming what changed and what was skipped