Security & Sandboxing: REXA is a general-purpose single-agent development harness. Review tool requests carefully and run commands inside configured Docker containers when working with sensitive repositories or permissions.

Docker SandboxBun Runtime
REXA Core•Continuous reasoning up to 60 steps

A general-purpose, single-agent development harness.

REXA understands a task, gathers context, reflects on its own plan, writes or edits code, runs commands, searches the web, investigates failures, and reports the result — all through one continuous conversation of up to 60 reasoning steps.

Runtime: Bun
Docker Sandbox
Pre-Execution Self-Reflection
Deterministic Verification
rexa-cli — session
| _ \  ___|  \/  /  \
| |_) | _|  \  / / _ \
| _ <| |__/ \ / /__ \
|_| \_\____/\_\/\_/   \_\
+-----------------------------------------------+
| REXA CLI v1.0.0 | Autonomous Agent Harness |
+-----------------------------------------------+
>Yo, it's me... REXA. What's the plan?
>Find why the auth test is failing and fix it.
*get_project_treerunning...
+get_project_treedone (0.3s)
*coding_context_toolrunning...
+coding_context_tooldone (0.2s)
*code_toolrunning...
+code_tooldone (0.1s)
*execute_commandrunning [bun test]
+execute_commanddone (3.1s)
rexa . 20:01

Found the issue -- missing null check on line 42 of auth.ts.

Fixed with a guard clause. All tests pass.

Agent Philosophy

Why REXA is more than a tool runner.

REXA is an autonomous agent, not a collection of disconnected commands. The model decides which capabilities are needed, calls them in sequence, observes their results, and continues until it can answer or complete the task.

Pre-Execution Plan Reflection

Before executing any tool call, REXA reflects on its own proposed plan — if the plan is flawed, redundant, or hallucinated, it scraps it and re-generates before touching anything.

Autonomous Sequencing

Rather than asking users to orchestrate toolchains, REXA maps state, evaluates next steps, and executes tools in sequence until verified completion.

60x

Deep Reasoning Window

Complex engineering tasks require iterative problem solving. REXA maintains deep memory and context across conversations of up to 60 reasoning steps.

100%

Ground-Truth Verification

REXA re-reads modified files directly from disk and runs tests in an isolated Docker container to reason from actual results rather than assumptions.

M-A

Multi-Agent Roadmap

Engineered to scale into specialized agents for deep research, planning, code synthesis, and scheduling under a unified single-agent command harness.

Deterministic Workflow

The 8-step autonomous development lifecycle.

A single request combines repository inspection, code changes, Git operations, command execution, and containerized verification.

01

Map project & locate files

Inspects workspace topology, locates relevant modules, and indexes project symbols.

02

Read context & implementation

Examines surrounding logic, type definitions, and dependencies before drafting solutions.

03

Reflect on proposed plan

Scrutinizes the proposed plan. If flawed, redundant, or hallucinated, scraps and re-generates.

04

Form focused code changes

Applies precise, minimal diffs using atomic create, write, or replace operations.

05

Re-read modified files

Reads the file back from disk to ground reasoning on actual file content rather than model memory.

06

Run tests in Docker sandbox

Executes typechecks, linting, and automated test suites inside an isolated container.

07

Inspect failures & iterate

Diagnoses stack traces, corrects edge cases, and repeats reasoning loop if needed.

08

Explain changes & verify

Provides a concise breakdown of modifications made and verification results.

Capabilities

Practical engineering capabilities.

Engineered as a pragmatic assistant for daily software engineering workflows.

Autonomous Agent Core

REXA reasons about multi-step development goals, maintaining state across a continuous session of up to 60 reasoning steps.

Pre-Execution Plan Reflection

Reflects on proposed execution plans before taking action. Scraps and regenerates flawed or redundant plans before touching files.

Docker Sandbox Execution

Commands, tests, and builds run inside an isolated Docker environment to ensure system security and reproducible results.

Contextual Repository Research

Maps project hierarchies, parses symbols, and retrieves surrounding dependencies to formulate well-grounded solutions.

Bun Runtime Performance

Powered natively by Bun for lightning-fast module resolution, script execution, and modern TypeScript support.

Extensible Capability Architecture

Designed to grow from a unified harness into specialized domain agents for research, planning, coding, and scheduling.

Developer Experience

Built for the terminal.

Connect your account to the REXA CLI in seconds. Generate a one-time temporary token from your dashboard and interact with your agent harness directly within your local development environment.

bash — 80x24cli authentication
$ rexa login
Authenticate REXA CLI with your web account.
? Enter CLI token: ••••••••••••••••••••
✓Authenticated successfully. Active session linked to Docker sandbox.

Independent Development

Engineered with a focus on simplicity and agency.

REXA is an independent project built by Subhamoy Datta with the goal of exploring what a practical, extensible AI development harness can become.

Ready to try REXA?

Create your account and generate a secure token to connect REXA to your terminal.