locode-core
The headless Rust core of locode, a custom coding agent: the
sample→dispatch→append loop, a typed tool registry, faithful per-harness tool
packs, and a provider/wire abstraction — shipped as a set of library crates
plus a minimal headless binary (locode-exec). No TUI lives here; that
belongs to a separate app built on these crates.
Why
locode-core is a distilled re-implementation of the agent cores of four studied coding harnesses (Claude Code, Codex, Grok Build, opencode). Each harness pack reproduces its harness's real tools and system prompt — names, schemas, caps, quirks — so different harness designs can be compared honestly, A/B, on the same engine and the same provider wire. The tool packs are also a first-class library surface: downstream consumers can drop the tools into their own agent loop without using our engine.
Quick start
# required (except with --api-schema mock)
# optional: provider endpoint override
# optional: model id override
# One task, headless: one JSON report on stdout, diagnostics on stderr.
Select the provider wire with --api-schema (anthropic | openai-responses
| mock, where mock runs keyless) and the stdout artifact with
--output-format (json | stream-json | text). See
cargo run -p locode-exec -- --help for the full surface.
LOCODE_BASE_URL defaults to the wire's native endpoint
(https://api.anthropic.com for anthropic, https://api.openai.com for
openai-responses); point it at any compatible gateway (e.g. OpenRouter) to
reach other providers over the same schema. LOCODE_MODEL defaults to
claude-sonnet-5 on the Anthropic wire and gpt-5-mini on the OpenAI
Responses wire, and LOCODE_API_KEY must match whichever endpoint you target.
To build and test everything:
Crates
| Crate | What it is |
|---|---|
locode-protocol |
Conversation model, tool call/result types, report envelope — pure types, no I/O |
locode-tools |
Tool trait, registry, and the one dispatch door — host-agnostic framework |
locode-packs |
Harness packs: faithful per-harness toolsets + system prompts |
locode-provider |
Provider trait, API-agnostic request type, and the wire implementations |
locode-host |
Filesystem/shell/path-jail seam — every side effect goes through here |
locode-engine |
The sample→dispatch→append loop and the Session driving API |
locode-core |
Facade: re-exports the driving API and the full tool surface |
locode-exec |
Minimal headless binary — exactly one JSON report on stdout |
Disclaimer
This is a personal project and is not affiliated with any company. The content does not reflect any specific company's projects, products or internal work.