# FuelLabs/fuel-specs

📝 Specifications for the Fuel protocol and the FuelVM, a blazingly fast blockchain VM.

Repository: https://github.com/FuelLabs/fuel-specs
Canonical: https://ross.abutalabs.com/products/fuel-specs
Homepage: https://fuellabs.github.io/fuel-specs/master
License: Apache-2.0
License Family: permissive
Topics: fuel, blockchain, fuelvm
Last push: 2026-04-14T08:54:16+00:00

## Health v2 (maintenance only)
Score: 57/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 77, release rhythm 8, longevity 100
- inputs: {"age_days": 2197, "days_push": 141, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1780, forks 702 (observed 2026-08-28T04:05:35.359730+00:00)

## What it is
The official specifications repository for the Fuel protocol and FuelVM, a fast verifiable blockchain virtual machine. It is a documentation project built with mdbook covering transaction formats, validity rules, cryptographic primitives, ABI, and the FuelVM instruction set.

## Use cases
- understand the FuelVM instruction set
- implement a Fuel transaction parser
- learn Fuel transaction validity rules
- build a tool that computes Fuel transaction or contract IDs
- implement the Fuel block header format
- verify Sparse Merkle Tree correctness against the spec test suite
- understand Fuel consensus parameters and gas costs

## When to choose
- you are implementing a Fuel client, VM, or toolchain and need normative protocol details
- you want to build tooling that parses or validates Fuel transactions
- you need authoritative reference material on the FuelVM architecture

## When to avoid
- you want runnable code or SDKs rather than specifications
- you are looking for a general-purpose blockchain tutorial rather than Fuel-specific protocol docs
- you need end-user documentation for Fuel wallets or apps

## Facets
- artifact type: learning-resource
- maturity: active
- function: documentation, interpreter, cryptography, testing
- domain: blockchain, documentation, developer-tools
- platform: cross-platform
- tags: blockchain-vm, fuel-protocol, specifications, fuelvm, mdbook, transaction-format, virtual-machine, cryptocurrency

## Member repositories
- FuelLabs/fuel-specs (main) score 57

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:35.359730+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:24:26.233947+00:00, confidence not recorded.
  - readme: https://github.com/FuelLabs/fuel-specs (fetched 2026-08-28T04:05:35.359730+00:00, sha 34828a830424)
  - homepage: https://fuellabs.github.io/fuel-specs/master (fetched 2026-08-29T11:03:35.653322+00:00, sha 3a1a8e717389)
  - site_page: https://docs.fuel.network/docs/specs/tx-format (fetched 2026-08-29T11:03:35.662318+00:00, sha 64468e6f64c8)
  - site_page: https://docs.fuel.network/docs/specs/tx-format/consensus_parameters (fetched 2026-08-29T11:03:35.664224+00:00, sha dd7f39fc699a)
  - site_page: https://docs.fuel.network/docs/specs/tx-format/transaction (fetched 2026-08-29T11:03:35.665940+00:00, sha 8461f0cb6e74)
  - site_page: https://docs.fuel.network/docs/specs/tx-format/upgrade_purpose (fetched 2026-08-29T11:03:35.668461+00:00, sha 21b2d16832d0)
  - site_page: https://docs.fuel.network/docs/specs/tx-format/policy (fetched 2026-08-29T11:03:35.670101+00:00, sha d65a9e01ba55)
  - site_page: https://docs.fuel.network/docs/specs/tx-format/input (fetched 2026-08-29T11:03:35.671944+00:00, sha bbbc052a972f)
  - site_page: https://docs.fuel.network/docs/specs/tx-format/output (fetched 2026-08-29T11:03:35.673864+00:00, sha 600e473625e3)
  - site_page: https://docs.fuel.network/docs/specs/tx-format/witness (fetched 2026-08-29T11:03:35.675400+00:00, sha 9ee1b18b458e)
- Data as of 2026-08-30T08:39:29.467469+00:00.