Done. The contracts and tests are committed on main as commit 2c70040, and all three checks pass.

What was delivered

• src/VestToken.sol: self-contained fixed-supply ERC-20 ("Vest Demo" / "VDEMO", 18 decimals). It mints the whole supply to the deployer in the constructor and has no mint, burn, owner or other admin path.
• src/LinearVesting.sol: ownerless single-beneficiary vault. The allocation is balance + released, so donations at any time join the curve. It vests nothing before the cliff, everything at the end, and a floored linear amount in between. Anyone can call release(), which reverts with NothingToRelease when nothing new has vested and with TransferFailed if the token returns false or reverts. No ETH, no revoke.
• test/VestToken.t.sol and test/LinearVesting.t.sol: 49 tests in total, covering every schedule point in the spec (before cliff, at cliff, midway, at and after end, odd totals, donations after start) plus constructor validation, permissionless release, absence of admin entry points, misbehaving-token failures, and fuzzed monotonicity and conservation invariants.
• foundry.toml pins solc = "0.8.26", disables ffi and grants no filesystem permissions. forge-std 1.16.2 is vendored as plain files under lib/ with no nested git metadata.
• README.md documents the schedule semantics, assumptions (plain ERC-20 only, rounding down, irreversible donations, fixed beneficiary), the deployment config parameters and their constraints, and operational responsibilities.

Verification results

Out of scope for this assignment

The deployment script, config/deploy.json, and the anvil proof in script/README.md belong to a separate assignment in this project. The root README already documents the config shape and constraints the script must enforce so the two pieces line up.

One leftover: forge init created a .vscode/ folder that the sandbox would not let me delete. It is untracked and not part of the commit.

Implemented the deployment script, JSON fixtures, wiring tests, and documentation.

Verified:

• Offline build and all 70 tests pass.
• Dry run succeeds without RPC.
• Local Anvil deployment and cast readbacks match.
• Invalid configs revert before deployment.

Commands and output are in script/README.md.

Fixtures live under script/config/ to comply with the permitted paths. No public network was used.

Done. The deployment script, configs, tests and the anvil proof are in place, and forge build plus forge test pass locally with 79 tests and no failures.

Why the previous attempt failed, and the fix. The selector 0xcdb6e4ac the verifier rejected is parseJsonArrayLength, a cheatcode the verifier's older forge does not implement. The new script never calls it. It counts beneficiaries by probing .beneficiaries[i] with keyExistsJson until the first missing index, and otherwise uses only long-established cheatcodes: envOr, parseJsonUint, parseJsonAddress, toString, readCallers, startBroadcast and stopBroadcast. I confirmed with traces that these are the only cheatcodes the script emits.

What was delivered

• script/Deploy.s.sol: run() reads DEPLOY_CONFIG and falls back to a built-in copy of the anvil config. Parsing, validation and deployment are separate public functions so tests drive them in memory and never touch the environment. Every rule (chain id, 1 to 20 entries, non-zero unique accounts, positive amounts, total within supply, valid schedule, uint64 ranges) is checked before startBroadcast, and the wiring is re-read and asserted before stopBroadcast.
• script/config/deploy.json for anvil accounts 1 to 3, and script/config/deploy.example.json with placeholder addresses. These live under script/config/ rather than a top-level config/ because that is the only allowed path for this assignment. Both READMEs say so.
• test/Deploy.t.sol: 30 tests covering parsing, wiring, actual release to beneficiaries, and every rejection with a check that no transaction or contract was produced.
• script/README.md: parameter table with defaults and the error each rule raises, exact dry-run and broadcast commands, and the recorded anvil transcript. The transcript shows the wrong chain id, duplicate beneficiary and over-supply configs reverting with nonce and block number unchanged, then the broadcast, then cast readbacks of each vault's balance, beneficiary and start.
• Root README.md: file tree and deployment section updated with the commands and defaults.

Two things to know

• Forge 1.8 prints a cosmetic "artifacts built from source files that no longer exist" warning about its script preprocessor on every forge script run, even after forge clean. It is recorded and explained in the README rather than hidden.
• The changes are left uncommitted in the working tree, since nothing was installed and the instructions only required committing installed dependencies. The temporary broadcast/ directory from the proof was removed.