classy_szlite Assistant (Claude Code plugin)
Specialized Claude Code assistance for
classy_szlite — a pure-JAX
cosmology code that exposes:
- CMB angular power spectra (TT, TE, EE)
- Linear and nonlinear matter Pk
- Cosmological distances (H(z), comoving, angular-diameter)
- Derived parameters (σ8, Ω_m, S8, ...)
- Halo-model tSZ Cl^yy (Arnaud-10 GNFW pressure profile)
…all backed by the high-accuracy v2 CosmoPower emulators used in
the ACT DR6 extended-cosmology analyses,
and entirely differentiable with jax.grad / jax.jacfwd.
Designed to compose with the
cobaya-claude-plugin
— enable both to get a full tSZ MCMC workflow.
What you get
-
/class-sz:explain — auto-loads when the conversation is about
classy_szlite, tSZ Cl^yy bandpower fits, GNFW / Arnaud pressure
profiles, the cl_yy_factory fast path, JAX gradient probes, or
cobaya wiring of a classy_szlite-backed theory. Bundles a focused
classy_szlite API + parameter reference.
-
/class-sz:tszfast [param=value …] — runs a quick Cl^yy
calculation through classy_szlite.cl_yy_factory; supports
parameter sweeps and jax.grad probes. Useful for sanity-checks
before a long MCMC.
-
/class-sz:build-likelihood <Name> [--data-dir DIR] — scaffolds
a standalone Gaussian likelihood (no SOLikeT dep) + classy_szlite
Theory + foreground Theory + a working cobaya YAML for a tSZ
Cl^yy bandpower dataset (binned bandpowers + N×N covariance — not
a y-map pixel likelihood). Uses cl_yy_factory so the per-step
cost is ~5 ms/eval after init.
-
class-sz-engineer subagent — specialist for end-to-end
classy_szlite + cobaya work (scaffold, install, run, summarise).
Use for heavy multi-step tasks where you don't want install / chain
output flooding the main thread.
Install
In any Claude Code session, run these three commands:
/plugin marketplace add https://github.com/borisbolliet/class-sz-claude-plugin.git
/plugin install class-sz@class-sz-claude-plugin
/reload-plugins
After /reload-plugins, /class-sz:explain, /class-sz:tszfast,
/class-sz:build-likelihood show in /help and the
class-sz-engineer subagent appears in the Agent picker.
To update later (after I push a new commit):
/plugin uninstall class-sz@class-sz-claude-plugin
/plugin marketplace remove class-sz-claude-plugin
/plugin marketplace add https://github.com/borisbolliet/class-sz-claude-plugin.git
/plugin install class-sz@class-sz-claude-plugin
/reload-plugins
Environment
The skills and the class-sz-engineer subagent assume:
- Python venv:
~/pyvenvs/py312-class_sz/bin/python (with
classy_szlite, cobaya, numpyro, getdist, jax)
- classy_szlite source (optional, for editable install):
~/GitHub/classy_szlite
- Emulator data:
~/class_sz_data/ede/ (or the path in
$CLASSY_SZLITE_DATA_DIR) — see
cosmopower-organization/ede
- Reference workflow data (ACT-DR6 may26 setup):
~/Desktop/class-sz-plugin-tests/ (data/, clyy_v2.py, clyy_v2.yaml,
may26.proposal.covmat)
Adjust paths in agents/class-sz-engineer.md and the skill
allowed-tools if your venv lives elsewhere.
Try it
/class-sz:explain
How do I sample profile parameters at fixed cosmology with NUTS?
/class-sz:tszfast P0=10 beta=5.0
/class-sz:build-likelihood ACTClyy --data-dir "~/Desktop/class-sz-plugin-tests/data"
Layout
.claude-plugin/marketplace.json # single-plugin marketplace
plugins/class-sz/
.claude-plugin/plugin.json # plugin manifest
skills/
explain/SKILL.md # always-on classy_szlite knowledge
explain/reference.md # loaded on demand
tszfast/SKILL.md # /class-sz:tszfast
build-likelihood/SKILL.md # /class-sz:build-likelihood
agents/
class-sz-engineer.md # subagent
License
MIT
