Decodie Overview

Decodie — Overview Mode

Generate a high-level overview of a file, directory, or project — answering "what is this and how is it organized" rather than line-by-line explanations. Produces a single summary entry per target, intended as an onboarding starting point.

This mode persists by default — overviews are saved as learning entries. Re-running on the same target overwrites the existing overview rather than accumulating versions.

This mode is read-only with respect to source code. You only read source files and write to the .decodie/ directory.

Activation and Argument Parsing

1. Extract the target path. If none provided, use the project root.
2. Validate the target. Confirm it exists and is a file or directory.
3. Determine target scope:
   • File — entry_points and dependencies may be omitted.
   • Directory — entry_points and dependencies are usually meaningful.
   • Project root — all four overview fields apply.
4. Canonicalize the target path for regeneration lookup:
   • File: relative path (e.g., src/utils/helpers.ts)
   • Directory or project root: relative path with trailing slash (e.g., src/auth/, ./)

Setup

1. Check if .decodie/ exists at the project root. If not, create it:

   • .decodie/index.json with { "version": "1.0", "project": "<directory-name>", "entries": [] }
   • .decodie/config.json with default preferences
   • .decodie/sessions/ directory
   • .decodie/rules/ directory

2. Load rules. Check for ~/.decodie/rules/*.md (global) and .decodie/rules/*.md (project). Read all .md files found. Treat their content as additional instructions controlling documentation output — tone, language, verbosity, format, audience. Project rules override global rules on conflict. If no rules exist, proceed with defaults.

3. Load the index summary. Run:

   bash scripts/summarize-index.sh "$(pwd)"
   

   If unavailable, read .decodie/index.json directly.

4. Determine session ID. Find the highest NNN for today in .decodie/sessions/ matching overview-YYYY-MM-DD-NNN, then increment.

Regeneration vs Fresh Entry

Before generating, check for an existing overview:

1. Read .decodie/index.json.
2. Find any entry where decision_type === "overview" and sources is [<canonicalized-target-path>].
3. If found (regeneration): reuse the existing id, generate fresh content, update the index entry in place. The previous session file is left on disk but no longer referenced.
4. If not found: generate a new entry with a fresh ID.

Generation Process

1. Read the target:

   • File: read in full.
   • Directory: list top-level entries, read structural files (package.json, composer.json, pyproject.toml, README.md, etc.), sample representative source files.
   • Project root: additionally inspect entry-point manifests and dependency manifests.

2. Identify four overview dimensions:

   • purpose (required) — 2-4 sentences describing what this code is for. Lead with intent, not implementation.
   • structure (required) — how the code is organized (sections, modules, key directories and their roles).
   • entry_points (optional) — callable surfaces: exported functions, CLI commands, HTTP routes, framework hooks. Omit if not meaningful.
   • dependencies (optional) — notable internal or external dependencies and what they provide. Omit trivia.

3. Write in plain prose. Avoid jargon-heavy bullet lists; the goal is human onboarding. Calibrate length to scope.

Entry Generation

Index entry metadata

• id: Reuse existing for regeneration; generate fresh otherwise. Format: entry-{unix-timestamp}-{random-4-hex-chars}
• title: e.g., "Overview: src/auth/ — token issuance and verification"
• experience_level: "foundational" (overviews are onboarding entry points).
• decision_type: "overview"
• topics: Lowercase kebab-case tags. Reuse existing tags.
• lifecycle: "active"
• sources: Array with exactly one entry — the canonicalized target path.
• references: For single-file overviews, one reference to the file. For directory/project, empty array.
• content_file: relative path to session file, e.g. sessions/overview-2026-03-27-001.json

Session entry content (overview shape)

Use the overview shape — different from standard entries:

• decision_type: "overview"
• purpose (required) — what the target code is for
• structure (required) — how the target is organized
• entry_points (optional) — callable surfaces
• dependencies (optional) — notable dependencies

Session Closure

1. Set timestamp_end.
2. Write a summary noting the target and whether this was fresh or regenerated.
3. Confirm:
   • Fresh: "Generated overview for <target> as entry <id> in session <session_id>."
   • Regeneration: "Regenerated overview for <target> (entry <id>)."

Data Format

See references/schema.md for the full .decodie/ data format.

Important Notes

• Always-latest, not append-only. Re-running overwrites the index entry.
• One entry per target. Do not fan out to per-file entries — that is analyze mode's job.
• Be honest about uncertainty. If the target's purpose is ambiguous, say so.
• Language-agnostic. Adapt to whatever language and framework the project uses.
• Self-contained data. The .decodie/ directory can be removed without affecting the project.