SourceIndex

How It Works

SourceIndex is the bridge between your codebase and your coding agent — it watches one side and answers the other.

Your Codebase

your-repo/
├─ src/api/routes.py
├─ src/auth/login.py
└─ src/core/models.py

Run sourceindex init once. Git hooks re-index on every commit, so the map never goes stale.

The Bridge

◆

Stays in sync with your repo and answers every agent request with a targeted roadmap.

Your Coding Agent

> implement rate limiting
✓ sourceindex subagent
→ editing routes.py:41–77

Works with Claude Code and OpenCode. SourceIndex registers as a subagent — replacing Claude Code's built-in Explore — so your agent gets the roadmap and starts building immediately.

What your agent actually receives

Not a search box — a compiled roadmap of the exact code the task touches, handed over before the first turn.

The roadmap 5 files · 6 read windows · 11 functions

beetsplug/discogs/__init__.py edit target L1–L52imports L85–L265

DiscogsPlugin.__init__L85–L108Configure Discogs API credentials and plugin options
DiscogsPlugin.item_candidatesL188–L197Get candidate tracks by searching matching releases
DiscogsPlugin.album_for_idL199–L226Fetch Release by Discogs ID; handle 401 reset auth; validate fields
DiscogsPlugin.get_search_query_with_filtersL235–L259Normalize query text and add fixed release-type filter
DiscogsPlugin.get_search_responseL261–L265Call discogs_client.search and return raw IDResponse data

beets/library/models.py L841–L886

Item.__getitem__L841–L852Field value, falling back to album if missing
Item.getL875–L886Field value with optional album fallback

test/plugins/test_discogs.py L363–L502

DGSearchQueryTestL363–L502Tests for search query and filter construction

beets/util/config.py L1–L26

sanitize_choicesL9–L26Filters, dedupes, and expands '*' in choice lists

beets/plugins.py L223–L245

BeetsPlugin.__init__L223–L245Plugin name/config, log filter, config verifier

Each window covers exactly the functions beneath it — no padding, no whole-file reads. The extra L1–L52 on the edit target is that file's imports block, so new imports land in the right place.

What it does to the run — coding agent

With SourceIndex

1task → sourceindex subagent

2read .sourceindex/sourceindex-output.txt

3read ×6 — every roadmap entry, at the listed ranges, in one turndiscogs/__init__.py 1–52 · 85–181 · library/models.py 841 · util/config.py 1 · test_discogs.py 363 · plugins.py 223

4todowrite

5edit discogs/__init__.pyfirst edit, 4 turns in

6edit discogs/__init__.py

7edit discogs/__init__.py

8todowrite

9bash pytest test_discogs.py

10bash pip install python3-discogs-client

11grep _make_release_from_positions

12bash pytest test_discogs.py

13bash pytest test_discogs.py

14todowrite

18turns $0.46cost

No file read twice. Tests green.

Without

1task → Explore subagentits own turns, its own tokens

2read ×2 discogs/__init__.py (whole file) · test_discogs.py 363

3grep ×2 "def plurality" · "get_search_query_with_filters"

4read ×2 util/__init__.py 811 · metadata_plugins.py 340

5grep "^from beets|^import beets"

6read test_discogs.py 1

7todowrite

8edit discogs/__init__.pyfirst edit, 7 turns in

9edit discogs/__init__.py

10edit discogs/__init__.py

11edit discogs/__init__.py

12edit discogs/__init__.py

13edit discogs/__init__.py

14edit discogs/__init__.py

15read discogs/__init__.py 57re-read — already had this file

16read discogs/__init__.py 244re-read

17todowrite

18bash pytest test_discogs.py

19bash pip install python3-discogs-client

20bash pytest test_discogs.py

21read test_discogs.py 363re-read

22bash pytest DGSearchQueryTest

23bash pytest test_discogs.py

24bash pytest DGSearchQueryTest

25bash git stash pop

26grep _make_release_from_positions

27read test_discogs.py 40re-read

28read test_discogs.py 92re-read

29read test_discogs.py 360re-read

30edit test_discogs.py

31bash pytest test_discogs.py

32todowrite

74turns $2.39cost

Six re-reads of two files. Tests green.

Real logs from beets, a popular GitHub repo. Task: add extra_tags support to the Discogs plugin — on Opus 4.6 through OpenCode. The roadmap saves turns, and keeps correctness. Check the benchmark for more results.

Try it on your repo

pip install sourceindex
cd /path/to/your/repo
sourceindex init

Once per repository — git hooks keep the index fresh after that. Full setup guide →

See It in Action

Index once, then watch your agent go straight to the right files instead of hunting for them.

See the Full Demo

Built for Real Codebases

Fast to set up, precise to the line, invisible in your day-to-day workflow.

40+ Languages

Python, TypeScript, Rust, Go, Java, C/C++, Ruby, PHP, Swift, Kotlin, and more.

Fewer Turns, Same Answers

Every graded run passed its tests in both arms, and no SourceIndex run used more turns than its baseline. The savings come out of exploration, not correctness.

Zero Workflow Change

After sourceindex init, day-to-day you do nothing. Your agent finds and uses the index on its own, and git hooks re-index only the files each commit touched.

Nothing to Configure

One SourceIndex key is all you need. Our hosted backend makes the indexing and search calls — no provider accounts, no model picking, no extra bills.

AST-Grounded

Line ranges validated against tree-sitter AST. Precise read windows for the agent.

Claude Code & OpenCode

First-class integration with both, auto-detected per repo. More agents on the way.

See the Full Benchmark

Get Early Access

SourceIndex is in private beta — we're onboarding our first small cohort of testers now. Tell us about yourself and we'll get you set up with an access key.

Request Access Read the Setup Guide

Your agent rediscovers your codebase on every task. Hand it the map instead.