Read the function, not the file.

One binary. Three verbs.

$ cargo install starlab-sym            # the binary is `sym`
$ sym ls src/ops.rs                # every symbol: line range + signature
src/ops.rs — 271 lines, 14 symbols
   10-15    pub struct LsOut
   58-104   pub fn read(file: &Path, symbol: &str) -> Result<ReadOut, String>
   ...
$ sym read src/ops.rs read         # one symbol, with its doc block
$ sym map src/ --budget 800        # files ranked by PageRank over the imports, cut at 800 tokens

Add --json for structured output and --est for a token estimate. Nested symbols are addressed by leaf or qualified path (Widget::new, Runner.helper, Server.Serve).

$ claude plugin marketplace add https://github.com/codylwalker/sym
$ claude plugin install sym@starlab

{ "sym": { "command": "sym", "args": ["mcp"] } }

The same verbs over any public repo, paid per call.

Managed agents, web agents and sandboxes without cargo get map and read over a git URL. The server clones shallowly, caches for an hour, and answers in the same shape as the CLI. It is also an MCP server over HTTP, one line in any client:

$ claude mcp add s2ar --transport http https://api.s2ar.dev/mcp --header "Authorization: Bearer <key>"
$ claude plugin install s2ar@starlab        # or: the same server as a plugin, with skills and free reminders; no key needed to start
tools: sym_map_repo $0.01 · sym_ls_repo · sym_read_repo · sym_find_repo $0.005 · sym_where_repo $0.01 · score_text $0.005 · assert_output $0.005 · inspect_x402 $0.005 · certify_image $0.01 · buy_credits
every paid tool takes an optional x402_payment argument (USDC on Base per call, no key); ten languages: Rust, Python, TypeScript/TSX, JavaScript, Go, Lua, C, C++, Java, Ruby

Over plain HTTP every route takes GET with query parameters or POST with a JSON body, and repo is owner/repo, github.com/owner/repo or the URL. Payment is the 402 handshake, in three rails ordered by how autonomous the agent can be.

GET https://api.s2ar.dev/v1/sym/read?repo=BurntSushi/ripgrep&ref=14.1.1&file=crates/core/flags/defs.rs&symbol=Glob%20as%20Flag

← 402 Payment Required
{ "x402Version": 1, "accepts": [ … ] }           # x402: USDC on Base, no account; v2 in the PAYMENT-REQUIRED header
{ "credits_card": { "5": "https://buy.stripe.com/…", … } }   # a human buys a pack; the key is shown once, then Authorization: Bearer
{ "how_to_pay": "…", "docs": "…", "example_get": "…" }   # every quote says how, and where the worked example is

← 200, paid
{ "ok": true, "text": "impl Glob as Flag (crates/core/flags/defs.rs, lines 2459-2512) …", "charged_usd": 0.005,
  "receipt": { "evidence_hash": "sha256:…", "cost_usd": 0.005, "determinism": "replayable" } }

The agent-side skill for cards is npx skills add stripe/link-cli: it answers the 402 on /v1/credits/buy, and the key in the response pays for every call after that. Nothing is charged for a failed request.

Session cost, cache reads billed.

Token-reduction numbers measured on one payload say little about what a session costs; several context compressors cost more than running nothing once caching is counted. So the number on this page is the median cost of a fixed task list run as fresh sessions with and without the plugin, on a pinned public repo, cache reads billed, losses included. The first full run says something we did not expect and will not hide: Claude Code already avoids whole-file reads on its own (it greps, then reads a range), so on file-anchored questions the plugin is close to a wash and the agent reached for sym in one session out of twenty-four. Where sym earns its keep is orientation (map), agents without grep or ranged reads (the hosted tier), and the measurement itself.

The harness is bench/ in the repo, with a README on how to run it on any plugin or mod and how to read the numbers; every run is published there, losses included. Run it on your own repo; the table above regenerates from bench/results/latest.json.

Free where it runs on your machine. Cents where we run it.

What each front returns.

The repo map resolves each file's imports to files in the tree (Rust mod/use, Python, JS/TS relative paths, Go packages, Lua require, C includes, Java imports, Ruby requires), runs PageRank over that graph with test files voting at a discount, and emits top-level signatures (twelve per file, then "+N more") until the budget is spent.