indexion readme — README Construction

Build project READMEs from templates, doc comments, hand-written prose, and per-package READMEs. This skill covers the construction side: scaffolding, generating, planning, assembling, and verifying. For evaluating existing documentation, see indexion-documentation.

Where things live

The conventions vary by project; check what actually exists before editing:

The first thing to check is git diff / ls -la for: a symlink on README.md, a doc.json (at root or under .indexion/readme/), and .indexion.toml. The presence of these tells you whether the README is hand-maintained, build-assembled, or a hybrid.

Workflow overview

doc init                      → .indexion/readme/template.md + doc.json (greenfield)
edit doc.json + docs/*.md     → declare sources of truth
doc readme --per-package      → cmd/<pkg>/README.md (API skeletons; non-overwriting)
hand-write each per-package README's Overview / Usage / Options / Examples
doc readme --config           → assembled root README
plan drift <prev> <new>       → verify the assembled output (or hand-edit) is purely additive

Step 1: Initialize (greenfield only)

indexion doc init <project-dir>

Creates .indexion/readme/template.md + .indexion/readme/doc.json. Skip this step on a project that already has doc.json or .indexion.toml pointing at one.

Step 2: Configure doc.json

{
  "$schema": "./schemas/doc-config.schema.json",
  "version": "1.0",
  "spec": "moonbit",
  "output": { "format": "markdown", "filename": "README.md" },
  "packages": [
    {
      "path": "cmd/<name>",
      "title": "<command name>",
      "include_in_root": true,
      "sections": ["overview", "usage"]
    }
    // …one entry per package that should appear in the assembled root README
  ],
  "root": {
    "output": "README.md",
    "sections": [
      { "type": "static",   "file": "docs/intro.md" },
      { "type": "toc",      "title": "Commands" },
      { "type": "packages", "filter": "cmd/**" },
      { "type": "static",   "file": "docs/installation.md" },
      { "type": "static",   "file": "docs/license.md" }
    ]
  }
}

Root section types:

• static — include a markdown file verbatim
• toc — insert a table-of-contents heading
• packages — pull in entries from the packages array, filtered by glob

Package fields:

• include_in_root — whether to include in the assembled root README
• sections — README headings to extract; honored by per-package extraction flows. Note that { "type": "packages" } in the root currently emits a table of package links, not the rich Overview/Usage expansion implied by per-package sections. See "Known limitation" below.

Step 3: Generate per-package READMEs

indexion doc readme --per-package src/ cmd/

Generates README.md in each package directory that doesn't already have one. Non-overwriting — existing per-package READMEs are left alone.

The skeleton is API-only (extracted from /// doc comments via KGF). Treat it as a starting point and hand-write the prose sections (Overview, Usage, Options, Examples) afterwards.

# Single package to stdout
indexion doc readme src/kgf/lexer/

# Single package to a file
indexion doc readme -o=README.md src/kgf/lexer/

Note on side effects: doc readme --template=<t> <paths...> (the template-based mode below) walks the given paths and auto-creates per-package READMEs for any package that lacks one — even without --per-package. If you run it on a broad path (cmd/, src/), expect new files in unrelated packages. Run with a narrow path or grep git status afterwards to clean up unintended creations.

Step 4: Write static content

Create docs/intro.md, docs/installation.md, etc. — whatever your root.sections references. These are the hand-written prose; the assembler pulls them in verbatim.

Step 5: Generate writing plans (optional)

indexion plan readme --template=docs/templates/readme.md --plans-dir=.indexion/plans src/

Emits per-section writing tasks for manual or LLM-assisted authoring.

Step 6: Assemble the README

# Config-driven (preferred; doc.json controls layout and packages list)
indexion doc readme --config=doc.json

# Template-driven (alternative; {{include:…}} and {{packages}} placeholders)
indexion doc readme --template=docs/templates/readme.md -o=README.md cmd/

The config path can live at repo root or under .indexion/readme/. With .indexion.toml's [doc] config_path = "…", the --config= flag becomes optional.

Step 7: Verify with plan drift

After regeneration or any hand-edit of the root README, verify the change is purely additive (no silent deletions, no reflowing of unrelated sections):

# Snapshot the previous version
git show HEAD:README.md > /tmp/README.before.md

# Compare against the new version
indexion plan drift --top=20 /tmp/README.before.md README.md

What to look for in the output:

• Drift terms in /tmp/README.before.md (missing on the other side): (none) — nothing was removed
• Drift terms in README.md (missing on the other side): … — exactly the new vocabulary you intended to add (command names, new flags, new concepts)
• Cosine similarity near 1.0 for a small additive change; substantially lower if you reshaped a section

For CI integration:

indexion plan drift --vocab-threshold=0.05 /tmp/README.before.md README.md
# exits 1 if cosine_distance > 0.05 — useful as a guard against accidental large rewrites

This same workflow applies to translated README pairs (README.md ↔ README-ja.md): cross-lingual drift detection works natively because vocab sub-tokenization delegates to the natural-language KGFs in kgfs/natural/.

Template syntax

The template file supports {{placeholder}} substitution:

.indexion.toml integration

[doc]
config_path = "doc.json"   # auto-loads doc.json without --config
per_package = true         # makes `doc readme <path>` default to --per-package

Explicit --config=… always takes priority.

Known limitation: packages root section produces a table, not rich expansion

The doc-config.schema.json permits sections: ["overview", "usage", …] on each packageEntry, but the current doc readme --config implementation does not expand those sections inline when emitting { "type": "packages" } in the root. The output is a markdown table of package links with empty descriptions.

Two practical consequences:

1. If the project's checked-in root README has rich per-command Overview / Usage paragraphs, they were not produced by doc readme --config as it stands now. They are hand-maintained. Diff doc readme --config -o=/tmp/regen.md against the checked-in README to see how much of it is hand-curated; very large diffs mean the README is mostly hand-maintained.
2. For new commands, you currently need to also hand-edit the rich section into the assembled README, in addition to adding the package entry to doc.json and writing the per-package README. Use the plan drift verification above to confirm the hand-edit only adds, never removes.

If you fix this limitation (so { "type": "packages" } honors per-entry sections), update this skill to remove this section.

Common pitfalls

"doc readme --per-package generated nothing"

• All packages already have READMEs. The command only creates new files, never overwrites. Delete existing READMEs first to regenerate.

"doc readme --template … on cmd/ created READMEs in packages I didn't touch"

• Template mode auto-generates missing per-package READMEs as a side effect. Either pass a narrow path, or revert unintended creations from git status.

"Auto-generated per-package READMEs are just API listings"

• By design. Hand-write Overview, Usage, Options, Examples. For CLI commands, the authoritative behavior comes from indexion <command> --help.

"My hand-edit to README.md will be wiped out by doc readme --config"

• It will if the assembler ever produces the rich shape (see "Known limitation"). Until then, the assembler produces a strict subset (the table) and your hand-edits to the rich sections survive. Always run the plan drift cross-check to be sure.

"README.md edit destroyed unrelated sections"

• Run plan drift HEAD:README.md README.md and look at the "missing on the other side" output for the previous version. If it lists anything other than (none), you removed content.