SourceIndex hands your agent a per-task roadmap of the code. Across 16 task × model pairs it came out ahead every single time — up to 5× cheaper.
SourceIndex is the bridge between your codebase and your coding agent — it watches one side and answers the other.
your-repo/ ├─ src/api/routes.py ├─ src/auth/login.py └─ src/core/models.py
Run sourceindex init once. The index updates in real time as your code changes, so the map never goes stale.
Stays in sync with your repo and answers every agent request with a targeted roadmap.
> 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.
Not a search box — a compiled roadmap of the exact code the task touches, handed over before the first turn.
DiscogsPlugin.__init__L85–L108Configure Discogs API credentials and plugin optionsDiscogsPlugin.item_candidatesL188–L197Get candidate tracks by searching matching releasesDiscogsPlugin.album_for_idL199–L226Fetch Release by Discogs ID; handle 401 reset auth; validate fieldsDiscogsPlugin.get_search_query_with_filtersL235–L259Normalize query text and add fixed release-type filterDiscogsPlugin.get_search_responseL261–L265Call discogs_client.search and return raw IDResponse dataItem.__getitem__L841–L852Field value, falling back to album if missingItem.getL875–L886Field value with optional album fallbackDGSearchQueryTestL363–L502Tests for search query and filter constructionsanitize_choicesL9–L26Filters, dedupes, and expands '*' in choice listsBeetsPlugin.__init__L223–L245Plugin name/config, log filter, config verifierEach 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.
No file read twice. Tests green.
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.
Index once, then watch your agent go straight to the right files instead of hunting for them.
Fast to set up, precise to the line, invisible in your day-to-day workflow.
Python, TypeScript, Rust, Go, Java, C/C++, Ruby, PHP, Swift, Kotlin, and more.
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.
After sourceindex init, day-to-day you do nothing. Your agent finds and uses the index on its own, and it updates in real time as your code changes.
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.
Line ranges validated against tree-sitter AST. Precise read windows for the agent.
First-class integration with both, auto-detected per repo. More agents on the way.
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.