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+# AGENTS.md — bee-js
+
+This file provides guidance to AI coding agents (Codex, Cursor, Copilot, etc.) when working with this repository.
+
+## Project Overview
+
+**bee-js** (`@ethersphere/bee-js`) is the official TypeScript/JavaScript client library for the [Ethereum Swarm](https://ethswarm.org/) Bee node. It wraps the Bee HTTP API into a type-safe SDK that works in both Node.js (18+) and modern browsers.
+
+- **Package**: `@ethersphere/bee-js`
+- **License**: BSD-3-Clause
+- **Key dependencies**: `axios` (HTTP), `cafe-utility` (binary helpers, crypto, types), `isomorphic-ws` / `ws` (WebSocket for PSS/GSOC), `semver`, `debug`
+- **Compatible Bee version**: see `engines.bee` and `engines.beeApiVersion` in `package.json`
+
+## Build Commands
+
+```bash
+npm install           # Install dependencies
+npm run build         # Full build: CJS + ESM + types + browser bundle
+npm run build:node    # CJS (dist/cjs/) + ESM (dist/mjs/) via tsc + babel
+npm run build:types   # Type declarations (dist/types/)
+npm run build:browser # Webpack UMD bundle (dist/index.browser.js)
+npm test              # Jest tests (requires a running Bee node)
+npm run check         # TypeScript type-check only (no emit)
+npm run lint          # ESLint + Prettier
+npm run depcheck      # Check for unused dependencies
+```
+
+### Build Pipeline
+
+1. **CJS**: `tsc -p tsconfig.json` to `dist/cjs/`
+2. **ESM**: `tsc -p tsconfig-mjs.json` to `dist/mjs/`, then babel appends `.js` import extensions
+3. **Types**: `tsc --emitDeclarationOnly` to `dist/types/`
+4. **Browser**: webpack UMD bundle to `dist/index.browser.js` (exposed as `window.BeeJs`)
+5. **Fixup**: `./build-fixup` patches `package.json` files in dist directories
+
+## Project Structure
+
+```
+src/
+  index.ts              Public exports
+  bee.ts                Bee class (~100 public methods)
+  bee-dev.ts            BeeDev class (dev/debug extensions)
+  chunk/                CAC and SOC implementations
+    bmt.ts              Binary Merkle Tree hashing
+    cac.ts              Content Addressed Chunks
+    soc.ts              Single Owner Chunks
+  feed/                 Feed reader/writer and identifiers
+  manifest/             Mantaray manifest handling
+  modules/              HTTP API call layer (one file per API group)
+    debug/              Debug/admin API modules
+  stamper/              Client-side postage stamp issuing
+  types/                TypeScript interfaces and constants
+  utils/                Shared utilities
+test/
+  unit/                 Unit tests (no Bee node required)
+  integration/          Integration tests (require a running Bee node)
+```
+
+### Key Source Files
+
+- `src/bee.ts` — Main `Bee` class with all public API methods
+- `src/bee-dev.ts` — `BeeDev` class extending `Bee` with dev-mode methods
+- `src/modules/*.ts` — HTTP-level wrappers for each Bee API group
+- `src/utils/typed-bytes.ts` — Typed-bytes classes (`Reference`, `BatchId`, `PrivateKey`, etc.)
+- `src/utils/tokens.ts` — `BZZ` and `DAI` fixed-point token arithmetic
+- `src/utils/http.ts` — axios wrapper with retry, abort signal, and error wrapping
+- `src/stamper/stamper.ts` — Client-side postage stamp assignment
+
+## Architecture
+
+### Typed-Bytes Pattern
+
+All Swarm identifiers are strongly typed via classes extending `Bytes` from `src/utils/bytes.ts`. Each enforces a fixed byte length. Constructors accept `Uint8Array | string | Bytes`.
+
+Key classes:
+- `PrivateKey` (32B) — Ethereum private key; can derive `PublicKey` and sign data
+- `PublicKey` (64B) — Uncompressed public key
+- `EthAddress` (20B) — Ethereum address with checksum encoding
+- `Reference` (32 or 64B) — Content hash; 64B for encrypted references; also accepts CID strings
+- `BatchId` (32B) — Postage batch identifier
+- `Topic` (32B) — Feed topic (often keccak256 of a string)
+- `FeedIndex` (8B) — Sequential feed index (big-endian uint64)
+- `Signature` (65B) — ECDSA signature; supports `recoverPublicKey`
+
+### Token Classes
+
+`src/utils/tokens.ts` provides immutable fixed-point arithmetic:
+- **`BZZ`**: 16 decimal digits (1 BZZ = 10^16 PLUR). Use `BZZ.fromDecimalString("1.5")`.
+- **`DAI`**: 18 decimal digits (1 DAI = 10^18 wei). Use `DAI.fromDecimalString("1.0")`.
+
+### Browser vs Node.js
+
+Platform-specific code uses `.browser.ts` variants resolved via the `"browser"` field in `package.json`:
+
+- `utils/data.ts` / `utils/data.browser.ts` — data preparation for uploads
+- `utils/collection.node.ts` / `utils/collection.browser.ts` — file collection building
+- `utils/tar.ts` / `utils/tar.browser.ts` — tar archive creation
+- `utils/chunk-stream.ts` / `utils/chunk-stream.browser.ts` — streaming chunk upload
+
+### Modules Layer
+
+Files in `src/modules/` make HTTP calls using the `http()` helper from `src/utils/http.ts`. The `Bee` class delegates to these; do not import modules directly from application code.
+
+### Stamper
+
+`src/stamper/stamper.ts` provides `Stamper` — client-side postage stamp issuing tracking 65,536 buckets locally. Create via `Stamper.fromBlank(signer, batchId, depth)` or resume with `Stamper.fromState(...)`.
+
+## Testing
+
+Tests require a running Bee node. Set environment variables:
+
+```bash
+JEST_BEE_URL=http://localhost:1633
+JEST_BEE_SIGNER=<private-key-hex>
+JEST_MANAGED_BATCH_ID=<64-char-hex>
+JEST_EXTERNAL_BATCH_ID=<64-char-hex>
+JEST_WITHDRAW_ADDRESS=<eth-address>
+
+npm test        # Run all tests
+npm run check   # Type-check only (no Bee node needed)
+```
+
+- Tests use `ts-jest` with a 4-minute timeout
+- Coverage collected from `src/**/*.ts`
+
+## Code Conventions
+
+- **Strict TypeScript**: `strict: true`, `alwaysStrict: true`, `skipLibCheck: false`
+- **Formatting**: Prettier + ESLint; run `npm run lint` before committing
+- **Imports**: Use `cafe-utility` for binary ops (`Binary`), type assertions (`Types`), async helpers (`System`), strings (`Strings`)
+- **Conventional commits**: enforced by commitlint — use prefixes `feat:`, `fix:`, `docs:`, `chore:`, etc.
+- **Errors**: throw `BeeError`, `BeeArgumentError`, or `BeeResponseError` from `src/utils/error.ts`
+- **Validation**: typed-bytes constructors validate byte length; use helpers in `src/utils/type.ts`
+- **Request options**: every `Bee` method accepts optional `requestOptions?: BeeRequestOptions` as the last parameter
+
+## Common Pitfalls
+
+- **Gateway vs full node**: PSS, GSOC, staking, stamps, and chequebook operations require a full node. Check with `isGateway()`.
+- **Stamp usability**: After `createPostageBatch`, stamps need block confirmations before use. Set `waitForUsable: true` (default) or poll `getPostageBatch` until `usable === true`.
+- **Encrypted references**: Are 64 bytes (128 hex chars); the `Reference` class handles both 32B and 64B.
+- **CID support**: `Reference` constructor accepts `bah5...` CID strings and auto-decodes them.
+- **Browser code**: Never use Node.js APIs (`fs`, `stream`, `path`) in shared code — use the `.browser.ts` pattern.
+- **BZZ amounts**: Methods accept a `BZZ` instance or raw PLUR string/bigint. 1 BZZ = 10^16 PLUR.
+- **Network parameter**: `Bee` constructor accepts `network: 'gnosis' | 'sepolia'` affecting block time used for TTL calculations.
+
+## Key Constants
+
+```typescript
+CHUNK_SIZE = 4096         // Swarm chunk payload size
+SECTION_SIZE = 32         // BMT hash section size
+BRANCHES = 128            // BMT branching factor
+STAMPS_DEPTH_MIN = 17     // Minimum postage batch depth
+STAMPS_DEPTH_MAX = 255    // Maximum postage batch depth
+```
+
+## Related Files
+
+- `CLAUDE.md` — identical guidance for Claude Code (if present)
+- `README.md` — user-facing documentation and quick-start
+- `CHANGELOG.md` — release history
+- `cheatsheet.ts` — example code snippets for common operations