classy_szlite Assistant

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

Local testing (no marketplace needed):

claude --plugin-dir ~/GitHub/class-sz-claude-plugin

From a marketplace (once published):

/plugin marketplace add <owner>/<marketplace-repo>
/plugin install class-sz@<marketplace-name>

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/plugin.json
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