CMB Data MCP Server
This server does not currently have a deployable release on Glama. Follow the repository's setup instructions to install and configure it for your MCP client, including any required credentials and local dependencies.
CMB Data MCP Server
MCP server for public CMB power spectra, lensing bandpowers and LCDM parameter chains
from Planck PR3 (2018), ACT DR6 and SPT-3G (D1 + 2018). It covers data access, quick and honest
chi2 checks against LCDM, publication-style plots, and cross-experiment comparisons. It is
part of the cosmo-*-mcp-server family (see docs/CONVENTIONS.md).
This is Phase 1 of ~/cmb_mcp_data_survey.md: spectra and chains only. It has no maps and
no compiled likelihoods (see the TODO list below).

Tools (13 science/meta + 4 dispatch)
tool | what it does |
| dataset registry: products, units, verified URLs, citations |
| server-side recipes (also exposed as MCP prompts) |
| TT/TE/EE/BB/PP bandpowers written to a tidy CSV (+ covariance |
| D_ell with errors, multi-experiment overlay, best-fit LCDM, residual panel |
| chi2 / PTE against a theory spectrum. Uses the full covariance and windows for ACT and lensing; diagonal (indicative) for Planck/SPT plotting products |
| camb LCDM spectra (optional dependency, lazy import, dispatchable). Falls back to the bundled Planck 2018 best-fit file |
| Planck/ACT/SPT [L(L+1)]^2 C_L^phiphi/2pi with LCDM, plus a fitted A_lens per experiment |
| downloads and extracts ONE public chain (Planck 2018 plikHM TTTEEE+lowl+lowE+lensing, 65 MB; ACT DR6 ACT-lite / P-ACT, 5–7 MB) |
| getdist marginal stats (mean, std, 68/95% limits). Dispatch kernel downloads the chain on the node |
| getdist triangle plot overlaying up to 3 chains |
| whisker plot of H0/S8/Om/ns/sigma8 from chains and cited published tables, with n-sigma tensions |
| hep-genesis IRI dispatch (family convention) |
Related MCP server: spectra-mcp-server
Datasets
key | access | content |
| bundled binned spectra + best-fit theory; unbinned spectra downloaded | PLA R3.01/R3.02 TT/TE/EE, low-ell BB, base_plikHM_TTTEEE_lowl_lowE_lensing minimum theory |
| download (287 kB) | ACT DR6 CMB-only (ACT-lite) sacc: 135 bandpowers, covariance, windows |
| bundled | SPT-3G D1 MV foreground-cleaned TT/TE/EE |
| bundled | SPT-3G 2018 TT/TE/EE MV bandpowers |
| bundled | 2018 conservative lensing bandpowers + CMB-marginalised covariance |
| bundled (extracted from the 361 MB tarball) | DR6 lensing baseline bins + covariance |
| bundled | D1 GMV lensing bandpowers, covariance, windows |
| download (65 MB) | single-family PLA zip, not the 11 GB grid |
| download | ACT-lite and P-ACT-lite LCDM Cobaya chains |
Provenance for every bundled file is in data/README.md.
Sanity checks (verified by tests)
Planck 2018 chain: H0 = 67.36 ± 0.54, Ωm = 0.3153 ± 0.0073, σ8 = 0.8111 ± 0.0060 (getdist output equals the PLA margestats).
Planck TT binned vs best fit: χ² ≈ 82.7 for 83 points. Lensing A_lens: Planck 1.01 ± 0.03, ACT 1.02 ± 0.03.
SH0ES vs Planck H0: 4.9σ. KiDS S8: −3.1σ. DES Y3 S8: −2.6σ.
Skills
cmb-tour, reproduce-planck-tt-spectrum, cmb-experiment-comparison,
h0-s8-tension-whisker, hpc-dispatch-handoff.
Install / run
uv venv --python 3.12 .venv && uv pip install --python .venv/bin/python -e ".[dev]"
uv pip install --python .venv/bin/python --only-binary :all: camb # optional (".[theory]")
.venv/bin/python -m mcp_server --transport stdio # or ./run_server.sh
.venv/bin/python -m mcp_server --transport streamable-http --port 8012
MPLBACKEND=Agg .venv/bin/python -m pytest -q # -m "not network" offlineKnown limitations
The Planck and SPT-3G D1 spectra are the release plotting products, which ship no covariance. Their χ² values are diagonal-only and indicative.
ACT DR6 χ² fixes A_act = P_act = 1.
The SPT-3G D1 lensing A_lens comes out ≈ 0.92. candl's lensing-systematics emulator and M_L response corrections are not applied, so this is a known bias, not a physical result.
The bundled theory stops at ℓ = 2508. ACT/SPT bins beyond that need camb (
lmax=6600).ACT chain Ωm is derived assuming Σmν = 0.06 eV. ACT burn-in is 0.3, since LAMBDA lists none for the lite chains.
TODO — Phase 2: pip likelihoods (not implemented)
Planck: HiLLiPoP (PR4 high-ℓ TT/TE/EE) and LoLLiPoP (PR4 low-ℓ EE/BB), via
planck-npipe/ cobaya.ACT: act_dr6_lenslike (full lensing likelihood with linear corrections), plus the ACT DR6 multi-frequency MFLike.
SPT: candl +
spt_candl_data(SPT-lite TT/TE/EE and D1 lensing with its systematics emulator).Tools:
evaluate_cmb_likelihood(theory_file, likelihood), plus a profile likelihood in one parameter (heavy, dispatchable).
TODO — Phase 3: maps (not implemented)
Planck PR3/PR4 SMICA/Commander maps and the lensing κ map (healpy), ACT DR6 maps / κ map (pixell), SPT-3G D1 maps.
Tools: map cutouts, power spectra from maps (namaster), cross-correlation with galaxy surveys.
This server cannot be deployed
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