Weak Lensing Surveys 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.
weak-lensing-mcp-server
MCP server ("Weak Lensing Surveys MCP Server", tool prefix wl) for the public
weak-lensing data vectors, redshift distributions, covariances and chains of
DES Y3, KiDS-1000, KiDS-Legacy and HSC Y3 (DES Y6: registered, not yet public).
It is part of the cosmo-*-mcp family, built from cosmo-mcp-template.
Datasets
key | products | access | source (verified 2026-11-04) |
des_y3 | xi+-, gamma_t, w(theta), n(z) source+lens, 1000x1000 cov; ~30 chains | download (28 MB FITS, 5-50 MB chains) | desdr-server.ncsa.illinois.edu/despublic/y3a2_files/{datavectors,chains}/ |
des_y6 | - | unreleased (y6key_products/ is empty) | desdr-server.ncsa.illinois.edu/despublic/y6a2_files/ |
kids_1000 | xi+-, COSEBIs, band powers, n(z), cov; MultiNest chains | download (17 MB tarball) | kids.strw.leidenuniv.nl/DR4/data_files/KiDS1000_cosmic_shear_data_release.tgz |
kids_legacy | xi+-, COSEBIs E/B, band powers E/B, n(z), cov; Nautilus chains | download (131 MB tarball) | kids.strw.leidenuniv.nl/sci_data/KiDS_Legacy_cosmic_shear_data_release.tar.gz |
hsc_y3 | real-space xi+- (Li+23), Fourier C_ell SACC (Dalal+23), n(z), cov | download (CosmoSIS standard library mirror); chains credentialed | raw.githubusercontent.com/cosmosis-developers/cosmosis-standard-library/main/likelihood/hsc_cosmic_shear/ |
Notes: the KiDS server's TLS chain fails with some Python default CA stores, so
downloads use a certifi-backed opener inside tools/datavectors/io.py. The HSC
portal (hsc-release.mtk.nao.ac.jp) returns HTTP 401 without HSC-SSP credentials.
HSC chains therefore raise an error with manual-download steps. Save the chain as
~/.cache/cosmo-mcp/weak-lensing-mcp-server/hsc_y3/<chain>.txt and the tools pick it up.
Nothing is bundled; the cache is ~/.cache/cosmo-mcp/weak-lensing-mcp-server ($COSMO_MCP_DATA).
Related MCP server: spectra-mcp-server
Tools
fetch_wl_datavector(dataset, statistic)- tidy CSV (bin1, bin2, angbin, x, value, error) + covariance .npyplot_shear_correlation- xi+ / xi- triangle of bin pairs (DES/KiDS paper style)plot_redshift_distributions- n(z) per tomographic bin, multi-surveyplot_covariance- correlation matrix, PD check, condition numbercompute_signal_to_noise- sqrt(d^T C^-1 d) with cross-covariancefetch_wl_chain- published chain -> slim CSV (weight, Om, sigma8, S8, h0, w)analyze_wl_chain(heavy, dispatchable kernelchains.kernels.chain_marginals) - marginals, mode/HPDplot_s8_om_contours- multi-survey 68/95% contours with Planck bandcompare_s8_constraints- S8 whisker plot vs Planck 2018 (0.832 +/- 0.013) and tension in sigmameta:
list_wl_datasets,describe_wl_dataset,list_wl_skills,load_wl_skill; dispatch tools from the template
Skills: wl-tour, s8-tension-across-surveys, reproduce-des-y3-shear-figure,
wl-datavector-inspection, hpc-dispatch-handoff.
Sanity numbers (this server, from the public chains)
chain | S8 (mean +/- std) | paper |
DES Y3 3x2pt LCDM | 0.776 +/- 0.018 | 0.776 +/- 0.017 |
KiDS-1000 COSEBIs | 0.751 +/- 0.022 (mode 0.760, max-post 0.760) | 0.759 +0.024/-0.021 (MAP, PJ-HPD) |
KiDS-Legacy COSEBIs | 0.814 +/- 0.019 | 0.813 +/- 0.018 (mean) |
HSC Y3 real space | credentialed chain - published value used | 0.769 +0.031/-0.034 |

Install / run
uv venv --python 3.12 .venv && uv pip install --python .venv/bin/python -e ".[dev]"
.venv/bin/python -m mcp_server --transport stdio # or ./run_server.sh
.venv/bin/python -m mcp_server --transport streamable-http # port 8013Optional extra: getdist (not required; contours use a weighted smoothed histogram). sacc is a core dependency (HSC Fourier C_ell + n(z)).
Tests: MPLBACKEND=Agg .venv/bin/python -m pytest -q (-m "not network" offline).
This server cannot be deployed
Maintenance
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