How do I install the Hammerhead Ecosystem skill?

Run npx skillmds@latest add majiayu000/hammerhead-ecosystem in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

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Which AI agents work with Hammerhead Ecosystem?

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Is Hammerhead Ecosystem free to use?

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Who published Hammerhead Ecosystem?

majiayu000 (@majiayu000) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Hammerhead Ecosystem by majiayu000 — Agent Skill

Name: Hammerhead Ecosystem
Rating: 4.666666666666667 (3 reviews)
Author: majiayu000

Hammerhead Ecosystem

HAMMERHEAD-Space Julia astrodynamics ecosystem overview and cross-cutting patterns. Use when working on any HAMMERHEAD-Space repository, when asking about package interdependencies, or when creating new packages in the ecosystem.

majiayu000 Updated Sep 9, 2026 567 repo stars

File contents

HAMMERHEAD-Space Astrodynamics Ecosystem

Package Dependency Graph

QLaw.jl ──> AstroPropagators.jl ──> AstroForceModels.jl ──> AstroCoords.jl
                                                          ├─> SatelliteToolbox ecosystem
SimsFlanagan.jl ──> Lambert.jl ──> AstroCoords.jl
AstroMeasurements.jl ──> AstroCoords.jl

Shared Conventions

Convention	Standard
Julia versions	1.10, 1.11
Formatter	JuliaFormatter BlueStyle (`style = "blue"`)
Static arrays	`StaticArrays` / `StaticArraysCore` everywhere
AD support	ForwardDiff, Enzyme, Mooncake, Zygote, PolyesterForwardDiff
Allocation testing	AllocCheck.jl on all hot-path functions
Type stability	JET.jl on all packages
Package quality	Aqua.jl on all packages
Struct constructors	`@with_kw` from Parameters.jl
SciML interface	`solve(Problem, Algorithm)` pattern from SciMLBase
Default branch	`master` (not `main`)

Core Design Principles

AD-first: All code must be differentiable. Use promote_type, avoid mutation, use SVector returns.
Zero allocations: Hot-path functions (acceleration, EOM) must pass @check_allocs.
Type stability: All exported functions must pass JET analysis.
SciML composability: Follow Problem/Solution/Algorithm pattern.
Multiple dispatch: Use type dispatch over if/else branching.

Standard State Representation

Position/velocity: [rx, ry, rz, vx, vy, vz] km, km/s in J2000 ECI
Parameters: ComponentVector(; JD=epoch_jd, μ=gravitational_param)
Time: elapsed seconds since epoch; Julian Date = p.JD + t / 86400.0

New Package Checklist

When creating a new package in this ecosystem:

Add .JuliaFormatter.toml with style = "blue"
Add typos.toml for spell checking
Set up Aqua.jl, JET.jl, AllocCheck tests
Use StaticArraysCore (not full StaticArrays) for minimal deps
Support Julia 1.10+ in compat
Follow AbstractX base type pattern
Document with # Arguments, # Returns, # References sections
Add AD differentiability tests against FiniteDiff

---name: hammerhead-ecosystemdescription: HAMMERHEAD-Space Julia astrodynamics ecosystem overview and cross-cutting patterns. Use when working on any HAMMERHEAD-Space repository, when asking about package interdependencies, or when creating new packages in the ecosystem.--- # HAMMERHEAD-Space Astrodynamics Ecosystem ## Package Dependency Graph ``` QLaw.jl ──> AstroPropagators.jl ──> AstroForceModels.jl ──> AstroCoords.jl ├─> SatelliteToolbox ecosystem SimsFlanagan.jl ──> Lambert.jl ──> AstroCoords.jl AstroMeasurements.jl ──> AstroCoords.jl ``` ## Shared Conventions | Convention | Standard | |---|---| | Julia versions | 1.10, 1.11 | | Formatter | JuliaFormatter BlueStyle (`style = "blue"`) | | Static arrays | `StaticArrays` / `StaticArraysCore` everywhere | | AD support | ForwardDiff, Enzyme, Mooncake, Zygote, PolyesterForwardDiff | | Allocation testing | AllocCheck.jl on all hot-path functions | | Type stability | JET.jl on all packages | | Package quality | Aqua.jl on all packages | | Struct constructors | `@with_kw` from Parameters.jl | | SciML interface | `solve(Problem, Algorithm)` pattern from SciMLBase | | Default branch | `master` (not `main`) | ## Core Design Principles 1. **AD-first**: All code must be differentiable. Use `promote_type`, avoid mutation, use `SVector` returns. 2. **Zero allocations**: Hot-path functions (`acceleration`, `EOM`) must pass `@check_allocs`. 3. **Type stability**: All exported functions must pass JET analysis. 4. **SciML composability**: Follow Problem/Solution/Algorithm pattern. 5. **Multiple dispatch**: Use type dispatch over if/else branching. ## Standard State Representation - Position/velocity: `[rx, ry, rz, vx, vy, vz]` km, km/s in J2000 ECI - Parameters: `ComponentVector(; JD=epoch_jd, μ=gravitational_param)` - Time: elapsed seconds since epoch; Julian Date = `p.JD + t / 86400.0` ## New Package Checklist When creating a new package in this ecosystem: - [ ] Add `.JuliaFormatter.toml` with `style = "blue"` - [ ] Add `typos.toml` for spell checking - [ ] Set up Aqua.jl, JET.jl, AllocCheck tests - [ ] Use `StaticArraysCore` (not full `StaticArrays`) for minimal deps - [ ] Support Julia 1.10+ in compat - [ ] Follow `AbstractX` base type pattern - [ ] Document with `# Arguments`, `# Returns`, `# References` sections - [ ] Add AD differentiability tests against FiniteDiff

Frequently asked questions