UNICEF Stats MCP

unicefstats-mcp

Experimental — not an official UNICEF product. Verify retrieved values against the UNICEF Data Warehouse before citing in publications. See Limitations.

MCP server for UNICEF child development statistics. Query 790+ child-focused indicators across 200+ countries with disaggregations by sex, age, wealth quintile, and residence. No API key required.

Indicators cover child mortality, nutrition, education, child protection, WASH (water/sanitation/hygiene), HIV/AIDS, immunization, early childhood development, and more. Many align with SDG targets, but the dataset is broader than SDGs alone.

Data source: UNICEF SDMX API

Identity

Property	Value
MCP identity	io.github.jpazvd/unicefstats-mcp
PyPI package	unicefstats-mcp
Canonical source	github.com/jpazvd/unicefstats-mcp
Data source	UNICEF Data Warehouse via SDMX REST API
Maintainer	Joao Pedro Azevedo (jpazvd)
Status	Experimental — not endorsed by UNICEF

Third-party aggregator listings (LobeHub, Smithery, mcp.so, Glama) are not controlled by the maintainer. Verify against the canonical source above.

Contents

• How it relates to the unicefdata packages
• How it compares to other data MCPs
• Landscape: MCP servers for official statistics
• Relationship to sdmx-mcp
• Quick Start
• Tools
• Demo
• Prompts
• Benchmark Results
• Deployment
• Development
• Contributing
• Limitations and Hallucination Risks
• Provenance and Ownership
• How to Verify This MCP
• License

Key documents

Document	Description
PROVENANCE.md	Data origin, ownership, distribution pipeline, verification steps
CHANGELOG.md	Version history (v0.1.0–v1.5.5) with sources cited
RELEASE.md	Release process checklist and version management
CONTRIBUTING.md	Development setup, code style, PR guidelines
CODE_OF_CONDUCT.md	Contributor Covenant v2.1
examples/RESULTS.md	Full 300-query benchmark analysis with EQA decomposition
examples/LITERATURE_REVIEW.md	Literature review: MCP servers for official statistics — ecosystem, patterns, evaluation, 15 papers
examples/LANDSCAPE.md	Landscape analysis: 20 servers reviewed in depth (March 2026), 92 catalogued with status labels (October 2026) — timeline, feature matrix, strengths/weaknesses
examples/results/related_work.md	Annotated bibliography — 15 papers on tool-augmented hallucination
examples/results/statistical_summary.md	Wilcoxon, bootstrap CI, McNemar tests on benchmark results
examples/MCP-DIRECTORY-STATS.md	Comprehensive directory of all official statistics MCP servers
examples/mcp-smoke-test/MULTIMODEL_SMOKETEST.md	Cross-model smoke test (Anthropic / OpenAI / Google / OpenRouter) for the v0.7.3 cross-provider generalisation question — design, rubric, ~$1 default run, path to full mini-EQA

How it relates to the unicefdata packages

unicefstats-mcp is not a replacement for the unicefdata packages in Python, R, or Stata. They serve different audiences:

	unicefstats-mcp	unicefdata (Python/R/Stata)
Audience	AI assistants (Claude, Cursor, Copilot)	Data scientists, researchers, analysts
Interface	MCP protocol (tool calls via JSON)	Native language API (library(), import, ssc install)
Use case	Conversational data exploration, quick lookups, AI-assisted analysis	Reproducible research, ETL pipelines, statistical analysis
Output	JSON (compact or full) optimized for LLM context	DataFrames, tibbles, Stata matrices
Scripting	No — single queries via AI chat	Yes — full programmatic control, loops, joins, transforms
Caching	Delegates to unicefdata	Built-in SDMX response caching
Bulk download	Limited (max 500 rows per call)	Unlimited — designed for full dataset pulls

Under the hood, unicefstats-mcp wraps the unicefdata Python package. Every tool call ultimately calls unicefdata.unicefData() or its metadata functions. Think of the MCP as a thin AI-friendly interface on top of the same data layer.

When to use which:

• Use unicefstats-mcp when you're chatting with an AI and want to quickly explore indicators, check values, or compare countries
• Use unicefdata (Python/R/Stata) when you're writing scripts, building dashboards, running regressions, or doing any reproducible analytical work

How it compares to other data MCPs

Servers are named by repository and carry a status label (official, independent, community or commercial) as defined in Status labels. "—" means the feature is not documented in that repository's public README. See About these tables for how counts are taken and how to propose a correction.

Feature	unicefstats-mcp (this repo)	data360-mcp (World Bank, official)	fred-mcp-server (community)	world_bank_mcp_server (community)
Tools	9 (search → metadata → data → code → identity + strict canonical lookup)	16 (search indicators/datasets → metadata → data → disaggregation → codelist lookup → list; summarize / rank / compare countries; country-group expansion; single- and multi-indicator Vega-Lite viz specs; API-URL; plus an interactive-choice UI tool)	3 (browse → search → get)	1 (get only)
Indicators	790+ child-focused indicators	Data360 catalogue, multiple databases (WB_WDI, WB_SSGD, …)	800,000+ economic series	~1,600 indicators
Countries	200+ (ISO3)	200+ (ISO3 REF_AREA)	US-focused (some intl)	200+ (ISO2)
Disaggregations	Sex, age, wealth quintile, residence	Sex, age, urbanisation (per indicator, via data360_get_disaggregation)	Frequency, seasonal adjustment	None
MCP Prompts	5 (compare_indicators, trend_analysis, country_profile, sdg_progress, write_unicefdata_code)	7	None	None
MCP Resources	6 (system-prompt, context, llm-instructions, categories, countries, glossary)	11 (system-prompt, context, agent-recipe, databases, codelists, data-schema, data-filters, metadata-fields, search-usage, viz/chart-grammar, …)	None	None
Output modes	Compact (5 cols) / Full (all cols)	SDMX-shaped JSON with a per-observation claim_id (8-char "proof-carrying numbers" hash); compact serializer for aggregation tools	JSON	CSV
Data summary	Value range, year range, country count	summarize_data, rank_countries, compare_countries tools; Vega-Lite chart specs	None	None
Pagination metadata	total_rows_available vs rows_returned	limit/offset with total_count, has_more, next_offset (MCP best-practice pattern)	limit/offset	None (hardcoded 20K)
Input validation	ISO3, sex, wealth, residence validated	Codelist resolution tool + server-side country-coverage check (required_country)	Zod schemas	None
Error guidance	error + tip with next steps	Structured error_code (e.g. http_error:search) + message, raised as MCP ToolError	HTTP status text	Raw exception
API key	Not required	Not required	FRED_API_KEY required	Not required
Truncation handling	rows_truncated flag + filter tips	Payload stripping to core fields with claim_id preserved (docs/payload_analysis.md)	None	None
Published	PyPI	PyPI	npm	No

Landscape: MCP servers for official statistics

This project is part of a growing ecosystem of MCP servers for international and official statistics. Tables group servers by the data source they wrap; the Status column says who maintains them, using the labels defined in Status labels.

About these tables

Status labels

Status describes who maintains a server, not its quality or the quality of its data.

• Official: published by the organisation that produces the data, or that operates the platform it is served from, under that organisation's account or announced on its own website. A qualifier marks maturity where the organisation states it: (beta), (lab), (pilot).
• Independent: built by staff of that organisation in a personal capacity, as stated in the README or the maintainer's profile, and not endorsed by the organisation. This repository is in this category.
• Community: built by individuals or groups with no stated affiliation to the data producer.
• Commercial: offered by a company as part of a product or a hosted or paid service, with no stated affiliation to the data producer.

Official refers to the server, not the data. Servers whose data are not official statistics, such as research estimates, are listed separately in the directory; a research producer that maintains its own server is labelled producer-maintained, not official.

When the evidence is ambiguous, we do not claim official or independent status: the row is labelled community and the note says why. Affiliations we cannot see can be added through the landscape-correction issue template below.

Counts and corrections

The comparison and landscape tables are a snapshot, not a registry. Every count (tools, prompts, resources, stars) describes what is visible on each repository's public default branch on the date of the commit that last touched the row — currently 2026-10-24 to 2026-10-27 — and the ecosystem moves faster than this README. The same rule applies to every server, including this one: we do not use figures supplied privately by a maintainer unless a public artefact backs them.

If you maintain one of these servers, or know one that is missing or mis-described, please open a landscape-correction issue with the repository link and what should change. Corrections, additions and clarifications are all welcome, and are applied with the date they were verified.

The World Bank entries were corrected in October 2026 after Olivier Dupriez and Aivin Solatorio of the World Bank pointed out that a community wrapper had been labelled as the Bank's server and the official data360-mcp was missing. Aivin's comparison of the official server is the basis of the data360-mcp column above. Thank you to both. The naming rule, the Status column and these label definitions came out of that exchange.

UN Agencies

Server	Data Source	Status	Tools	SDMX	Published
unicefstats-mcp (this repo)	UNICEF Data Warehouse	independent	9	Yes	PyPI
sdmx-mcp	Any SDMX registry	official (UNICEF DRP, beta)	31	Yes	No (Docker / Fly)
UN System Data Commons	data.un.org — public data from 26 UN entities (Data Commons platform, launched 17 Sep 2026)	official (UN DESA / UNSD)	2	No	Hosted MCP endpoint
unicef-datawarehouse-mcp	UNICEF Data Warehouse	community (built by Tryolabs; UNICEF involvement not stated)	3	Yes	No
faostat-mcp	FAO FAOSTAT	community	23	No	PyPI
uis-mcp-server	UNESCO UIS	community	5	No	Remote
ilostat-mcp-server	ILO ILOSTAT	community	9	Yes	npm
who-gho-mcp-server	WHO Global Health Observatory	community	6	No	npm
un-comtrade-mcp-server	UN Comtrade	community	9	No	npm
unhcr-opendata-gateway-mcp	UNHCR open data (federating gateway)	independent (UNHCR staff)	8	No	No
mcp_unhcr	UNHCR refugee data	community	5	No	No
medical-mcp	WHO GHO / FDA / PubMed	community	18	No	npm

International Organizations

Server	Data Source	Status	Tools	SDMX	Published
data360-mcp	World Bank Data360	official (World Bank)	16	No	PyPI
world_bank_mcp_server	World Bank Open Data API	community	1	No	No
fred-mcp-server	FRED (800K+ series)	community	3	No	npm
imf-data-mcp	IMF (IFS, BOP, WEO)	community	5	Yes	No (uvx from Git)
OECD-MCP	OECD (5,000+ datasets)	community	9	Yes	npm
eurostat-mcp	Eurostat EU statistics	community	7	Yes	No
ecb-mcp	European Central Bank	community	8	Yes	npm

National Statistics Offices

Server	Data Source	Status	Tools	Published
us-census-bureau-data-api-mcp	US Census Bureau	official	5	No
esankhyiki-mcp	India MoSPI / NSO	official (beta)	4	No
datagouv-mcp	France data.gouv.fr	official (platform operator)	10	Hosted
McpDiffusion	France INSEE	official (lab, beta)	12	Hosted (beta)
Idescat MCP	Catalonia (Idescat)	official	7	Hosted
us-gov-open-data-mcp	40+ US Gov APIs	community	300+	npm
ibge-br-mcp	Brazil IBGE (227 tests)	community	23	npm
ukrainian-stats-mcp-server	Ukraine SDMX v3	community	8	npm
istat_mcp_server	Italy ISTAT SDMX	community	8	No
mcp-statcan	Statistics Canada	community	—	PyPI (uvx)
swiss-statistics-mcp	Switzerland BFS	community	15	PyPI (uvx)
korea-stats-mcp	Statistics Korea (KOSIS)	community	—	npm
estat-mcp	Japan e-Stat	community	4	PyPI

Known gaps

Community servers now cover UNESCO UIS (since February 2026), WHO GHO and UN Comtrade (since May 2026) and ILOSTAT (since August 2026), so those are no longer open gaps; none is maintained by the agency itself. Still no MCP server found (2026-10-26) for UNDP/HDI, the UNSD SDG Global Database API (the UN System Data Commons endpoint covers some SDG series), UN DESA Population, UNAIDS, WFP or WTO; BIS has no dedicated server, though the community aggregator openecon-data queries it. No official server was found from Eurostat, the IMF, the OECD or any central bank. The tables above are a selection; the directory below lists 92 servers for official statistics, plus research and other related sources and a long-tail list.

Full directory with install commands: MCP-DIRECTORY-STATS.md

Relationship to sdmx-mcp

UNICEF also maintains sdmx-mcp, a generic SDMX protocol MCP server. The two servers are complementary, not competing:

	unicefstats-mcp (this repo)	sdmx-mcp
Scope	UNICEF child development data only	Any SDMX registry (UNICEF, Eurostat, OECD, ...)
Tools	7 (analyst-friendly, 4-step workflow)	23 (SDMX power-user, structural queries)
Data layer	Wraps unicefdata Python package	Direct SDMX REST API calls via httpx
Output	Formatted for LLMs (compact tables, summaries, tips)	Raw SDMX-JSON/CSV
Accuracy (EQA)	0.891 (v0.7.3 + fixes)	0.074
Hallucination	hall_b 1.00% (mcp060) / 2.25% (mcp073) — below the no-tools hall_a baseline (2.50%)	0% T1 / 0% T2
Cost per query	~$0.04	$0.087
Latency	~10s avg	60s avg

Key tradeoff: unicefstats-mcp is dramatically more accurate (EQA 0.891 vs 0.074) because its formatted output is optimized for LLM parsing. sdmx-mcp achieves zero hallucination on absent-data queries through aggressive assistant_guidance fields and a validate_query_scope pattern; its accuracy floor is too low to be useful, but the refusal discipline is exemplary. unicefstats-mcp v0.7.3 + fixes is the first version where MCP demonstrably makes the model safer than the no-tools baseline on absent-data queries (hall_b < hall_a), achieved without sdmx-mcp's accuracy cost.

When to use which:

• Use unicefstats-mcp for UNICEF child development analysis — it's simpler, faster, and far more accurate
• Use sdmx-mcp when you need to query non-UNICEF SDMX registries, explore dataflow structures, or work with hierarchical codelists

Full 3-way benchmark (LLM alone vs unicefstats-mcp vs sdmx-mcp): examples/results/

Quick Start

pip install unicefstats-mcp

Claude Code

Add to ~/.claude/.mcp.json:

{
  "mcpServers": {
    "unicefstats": {
      "command": "unicefstats-mcp"
    }
  }
}

Cursor / VS Code

Add to your MCP settings:

{
  "unicefstats": {
    "command": "unicefstats-mcp"
  }
}

What v1.1.0 adds

v1.1.0 is additive: v1.0.0's ambiguity_flag, candidates, and abstain_instruction still fire unchanged on ambiguous queries. v1.1.0 layers four new advisory envelope fields on top:

• requires_confirmation — true when the server wants the assistant to pause for user input
• recommended — the server's preferred next action (code, country, year, or tool)
• assistant_guidance — short natural-language hint the LLM can paraphrase
• next_step — a structured tool/parameter suggestion the LLM can chain into

Decision order (4 stages): strict canonical lookup → ambiguity check (v1.0.0 fields) → confirmation gate (requires_confirmation) → advisory hints (recommended / assistant_guidance / next_step).

Verdict: ALLOW (no behavioural regression; advisory fields fire on 23/30 Sonnet and 26/30 Haiku paired stuck queries; see internal/v1.1.0_design/ab_results.md).

What v1.5.x adds (Jun 2026)

The v1.5.x series targeted the long tail of cases where the v1.0.0/v1.1.0 ambiguity gate fired but the model still couldn't pick the right indicator. Six releases shipped over 7 days, all additive to the v1.1.x decision order.

version	scope	mechanism
v1.5.0	Search-layer ambiguity reductions	Single-dataflow guard at heuristic Path B; all-matches accumulation in the differentiator; tiered fuzzy synonym scorer (data360-mcp pattern); cooperative abstain_instruction (faostat-mcp pattern)
v1.5.1	Tier 2c misroute fixes	Jaccard threshold bump (70→75); substring tier length-ratio guard (≤1.5); explicit antonym synonyms (unimproved drinking water → WS_PPL_W-UI); explicit qualifier synonyms (antenatal care 4+ visits → MNCH_ANC4)
v1.5.2	Custodian-agency defaults	CURATED_PREFERRED entries default education completion (ED_CR_L1/L2/L3_UIS_MOD) and out-of-school rate (ED_ROFST_L1/L2/L3_UIS_MOD) queries to the UIS modelled series per SDG 4 custodian convention. WASH JMP headlines (WS_PPL_W-I, WS_PPL_H-B) and the antonym-safe WS_PPL_W-UI ordering guard. Every entry's dimension_hint explicitly lists the alternative versions in the data warehouse
v1.5.3	Long-tail curated clusters	PT_F intimate-partner violence (SDG 5.2.1), PT_F sexual violence by 18 (SDG 16.2.3), MNCH_BIRTH18, PT_CHLD_5-17 child labour, ED_ROFST_L02, HVA_PED_LOST (UNAIDS AIDS-orphaned children)
v1.5.4	Copilot-driven correctness fixes	Removed misleading 15-19 synonym from the PT_F 15-49 default; reworded HVA_PED_LOST dimension_hint to say "AIDS-caused combined" (not "all-cause")
v1.5.5	Batch-use hardening (opt-in)	Two new env vars: UNICEFSTATS_SDMX_THROTTLE_MS (inter-call delay) and UNICEFSTATS_SDMX_RETRY_403=1 (exponential backoff 30/60/120s on 403s). Default behaviour unchanged for normal use; recommended for large-batch / benchmark scenarios

Empirical validation — v1.5.5 1484-cell paired re-validation against the v1.2.4 Jun 1 baseline measured mean EQA 0.749 (+29.1pp, p = 2×10⁻¹⁰⁵) on the v9 Arm B sample (a different, larger benchmark than the 300-query EQA test below). See Benchmark Results for both scoreboards.

Curated-agency default policy — for indicator families where the catalogue ships both an administrative-data series and a custodian-agency modelled series (UIS for education, JMP for water/sanitation, WHO/UNICEF Joint Estimates for nutrition), v1.5.x defaults natural-language queries to the modelled / custodian series and surfaces the other variants in dimension_hint. Users who explicitly want the raw / administrative figures can re-route via the hint; the LLM has full visibility of both.

Tools

Tool	Purpose	API call?
search_indicators(query, limit)	Find indicators by keyword	No
list_categories()	Browse thematic groups (CME, NUTRITION, EDUCATION, ...)	No
list_countries(region)	List countries with ISO3 codes	No
get_indicator_info(code)	Full metadata, SDMX details, available disaggregations	No
lookup_by_code(code)	v1.0.0 Strict canonical-code lookup (rejects natural-language input with abstain instruction)	No
get_temporal_coverage(code)	Available year range and country count	Yes (lightweight)
get_data(indicator, countries, ...)	Fetch observations with optional disaggregation filters	Yes
get_api_reference(language, function)	unicefdata package API reference (Python/R/Stata)	No
get_server_metadata()	Server identity, version, provenance, data source	No

Workflow

1. search_indicators("child mortality")     → find indicator codes
2. get_indicator_info("CME_MRY0T4")         → check disaggregations & SDMX details
3. get_temporal_coverage("CME_MRY0T4")      → check year range
4. get_data("CME_MRY0T4", ["BRA", "IND"])   → fetch data
5. get_api_reference("python", "unicefData") → get code template to continue in a script

Resources

The server exposes six MCP resources clients can load for guidance and reference data:

URI	Purpose
unicef://system-prompt	Recommended system prompt — operating loop + temporal-frontier check + anti-extrapolation directive (load at session start)
unicef://llm-instructions	Full DO/DON'T rules, common mistakes, and anti-fabrication guidance
unicef://context	Runtime context — current_date / current_year for temporal-query sanity checks
unicef://categories	All indicator categories with counts
unicef://countries	ISO3 codes and country names
unicef://glossary	Disaggregation codes and indicator-prefix legend

The system-prompt and context resources address the T2 hallucination failure mode (model fabricating values for years beyond the data frontier). Pattern adopted from the World Bank data360-mcp server. See CHANGELOG entry for v0.5.0.

Scope: UNICEF DW indicators only

unicefstats-mcp searches and serves the UNICEF Data Warehouse SDMX catalog — approximately 790 child-focused indicators across mortality, nutrition, education, child protection, WASH, HIV/AIDS, immunization, and early childhood development. Indicator codes follow UNICEF conventions (e.g. CME_MRY0T4, NT_ANT_HAZ_NE2, ED_ANAR_L1).

Codes from other organisations are out of scope. The MCP cannot find, resolve, or fetch them because they do not exist in the UNICEF SDMX catalog. Examples of out-of-scope code families:

Source organisation	Prefix examples	Typical content
World Bank WDI	SI.POV.DDAY, NY.GDP.PCAP.PP.KD, SE.PRM.NENR	Poverty, GDP, broader education
World Bank ASPIRE	per_allsp.cov_pop_tot, per_*	Social protection coverage
ILO / ILOSTAT	EIP_*, EAP_*, DF_*_SEX_RT	Labour, employment, NEET
UNESCO UIS	UIS.*	Education finance, learning outcomes

These codes will return no hits from search_indicators and a not-found error from get_data. The refusal is correct behaviour, not a bug.

For cross-organisation queries, use a sister MCP:

• data360-mcp — the World Bank's official server for its Data360 platform, covering WDI, ILO, UN, and other official providers under one tool surface.
• world_bank_mcp_server — community wrapper (anshumax) around the World Bank Open Data API only; not a World Bank product.

For SDMX power-user queries against arbitrary registries (Eurostat, OECD, national NSOs), see sdmx-mcp — the generic SDMX protocol server discussed under Relationship to sdmx-mcp.

The scope boundary was sharpened in v1.1.1 after the v9 edge-test sample surfaced three prompts whose ground-truth codes (SI.POV.DDAY, NY.GDP.PCAP.PP.KD, per_allsp.cov_pop_tot) sit in the World Bank universe rather than the UNICEF Data Warehouse. Full write-up: internal/v1.1.0_design/ambiguity_forensic.md sections C-4 to C-6 (dev repo only).

Understanding UNICEF indicator codes

Why this matters — the MCP's semantic layer

UNICEF SDMX indicator codes look cryptic on first contact — PT_F_20-24_MRD_U18, NT_ANT_HAZ_NE2, TRGT_2030_IM_DTP3 — and most of an LLM's failure modes on this data start with picking the wrong code. The single biggest piece of added value this MCP offers over a raw SDMX endpoint is exposing the semantic structure inside those codes so the assistant can disambiguate without guessing. The implementation lives in src/unicefstats_mcp/differentiator.py (segment-level suffix meanings and base/variant explanation) and src/unicefstats_mcp/indicator_resolver.py (natural-language synonyms and known ambiguous tokens). v1.1.1 added a query-aware CURATED_PREFERRED dimension_hint that tells the resolver which code from a family to surface for a given phrasing (e.g. "target" → TRGT_*, "modelled" → *_MOD, "child" → _T total rather than a sex-disaggregated variant).

This section documents the conventions the MCP relies on so users and downstream agents can read codes directly, and so reviewers can audit the resolver's choices.

Anatomy of a UNICEF code

UNICEF DW codes are concatenations of dot-free, underscore-delimited segments, read left-to-right from broadest to most specific. Take a layered protection indicator from the catalog:

PT_F_20-24_MRD_U18
│  │ │     │   │
│  │ │     │   └── Marriage cutoff:        U18   = first union before age 18 (SDG 5.3.1)
│  │ │     └────── Indicator class:        MRD   = ever-married / in-union
│  │ └──────────── Age band (cohort):      20-24 = women 20-24 (retrospective denominator)
│  └────────────── Population restriction: F     = female-only indicator (women/girls)
└───────────────── Family prefix:          PT    = Child Protection

Read out loud: "Child Protection / female respondents / cohort aged 20-24 / ever-married / before age 18" — i.e. the share of women aged 20-24 who were first married before 18. Note that the F here is not a sex-disaggregation suffix appended to a sex-neutral parent; it is a population-restriction marker built into a family of indicators that only exist for female respondents (FGM, child marriage, anaemia in women, antenatal care). See "Population restrictions vs sex disaggregation" below.

The same left-to-right reading applies to the nutrition anthropometric pattern:

NT_ANT_HAZ_NE2
│  │   │   │
│  │   │   └── Threshold:    NE2 = below -2 SD (NE = "negative end", 2 = SD count)
│  │   └────── Metric:       HAZ = Height-for-Age Z-score
│  └────────── Sub-family:   ANT = Anthropometry
└───────────── Family:       NT  = Nutrition

NT_ANT_HAZ_NE2 is the stunting prevalence indicator for children under 5. To get the sex-stratified value, query the indicator with the SEX dimension filter (get_data(indicator='NT_ANT_HAZ_NE2', sex='F')), not by appending _F to the code — see the next subsection.

And the derived-metric pattern, which the v1.1.1 query-aware scoring is specifically tuned for:

TRGT_2030_IM_DTP3
│    │    │  │
│    │    │  └──── Antigen / dose: DTP3 = third dose of DTP
│    │    └─────── Family:         IM   = Immunization
│    └──────────── Target year:    2030 = SDG horizon
└───────────────── Derived metric: TRGT = country-set target value

The combinatorial reading — family → sub-family → metric → threshold/age band → disaggregation token — is the unwritten contract behind almost every code in the catalog. The tables below enumerate the parts.

Topic prefixes (families)

The first segment is the topical family. The top 10–12 prefixes in the catalog cover the vast majority of child-focused indicators:

Prefix	Meaning	Example code
CME	Child Mortality Estimates — mortality rates by age bracket (neonatal, infant, under-5, childhood, stillbirth)	CME_MRY0T4 (under-5 mortality), CME_SBR (stillbirth rate)
NT	Nutrition — anthropometry, anaemia, birthweight, micronutrients	NT_ANT_HAZ_NE2 (stunting), NT_BW_LBW (low birthweight)
ED	Education — completion rates, literacy, attendance by ISCED level	ED_CR_L1 (primary completion), ED_15-24_LR (youth literacy)
WS	WASH — water, sanitation, hygiene; population-level access	WS_PPL_W-SM (safely managed water)
IM	Immunization — vaccine coverage by antigen / dose	IM_BCG, IM_DTP3, IM_MCV1
MNCH	Maternal, Newborn & Child Health — antenatal care, skilled birth attendance, early childbearing	MNCH_ANC1, MNCH_SAB, MNCH_BIRTH18
ECD	Early Childhood Development — learning materials, parental stimulation, attendance	ECD_CHLD_LMPSL (learning materials)
PT	Child Protection — FGM, child marriage, violent discipline	PT_F_20-24_MRD_U18 (married before 18)
HVA	HIV/AIDS — ART coverage, prevalence, adolescent indicators	HVA_ADOL_ART_RECEIVE
PV	Child poverty — monetary and multidimensional	PV family
COD	Causes of death — disease- and condition-specific mortality / morbidity	COD_ACUTE_HEPATITIS_A
DM	Demography — household composition, population structure	DM_HH_U18 (households with member under 18)
MG	Migration — child migrants, displacement	MG family
GN	Gender / adolescent girls (often cross-cuts NT)	GN_ANEMIA_ADOL_GRL
TRGT	Country-set targets (see "Derived metrics" below)	TRGT_2030_*
HAZARD	Hazard exposure (climate, conflict, disaster)	HAZARD family

The full mapping of natural-language phrases to these prefixes lives in indicator_resolver._SYNONYMS — e.g. "stunting" → NT_ANT_HAZ_NE2, "child marriage" → PT_F_20-24_MRD_U18, "BCG" → IM_BCG.

Methodology and provenance suffixes

A trailing segment often signals how the value was produced, not what was measured. These suffixes are central to the v1.1.1 query-aware scoring because users almost always want either "survey" or "modelled" but rarely both.

Suffix	Meaning	Example code
_MOD	Modelled estimate (joint-estimation group output, e.g. UIS for education, IGME for mortality)	ED_CR_L1_UIS_MOD (modelled primary completion)
_MERGE	Merged across multiple source surveys / years into a single comparable series	ECD_CHLD_LMPSL_MERGE
_PRXY	Proxy indicator — a related variable used in lieu of the conceptually exact one	ECD_CHLD_LMPSL_PRXY
_NEW	New / revised methodology series (often runs alongside a legacy series for one cycle)	*_NEW
_NUMTH	Numerator / threshold variant — alternate cut used by some agencies	*_NUMTH
_AGG	Aggregate (regional or income-group rollup rather than country observation)	*_AGG
_UIS	UNESCO Institute for Statistics source / methodology	ED_CR_L1_UIS_MOD

The MCP's differentiator.py:_SUFFIX_MEANINGS table is the canonical source. When two codes differ only in this trailing segment, explain_difference() reports them as base vs. variant (e.g. ECD_CHLD_LMPSL as base, _MERGE and _PRXY as derivation variants).

Population restrictions vs sex disaggregation

This distinction is easy to miss and routinely trips up downstream agents.

Population restriction (built into the code). Some UNICEF indicators only exist for one sex because the underlying measurement only applies to one sex: FGM prevalence, child-marriage cohorts, anaemia in women of reproductive age, antenatal care coverage. In those families, an F segment near the start of the code (PT_F_*, NT_ANE_WOM_*, MNCH_BIRTH18, antenatal-care codes) is a population-restriction marker that is part of the indicator's identity. There is no PT_M_20-24_MRD_U18 counterpart for child marriage; the indicator is defined on female respondents. Treat the F here as part of the indicator name, not as a disaggregation switch.

Sex disaggregation (SEX dimension filter, at query time). For indicators that are defined on both sexes (under-5 mortality, primary completion, stunting, literacy), sex is not encoded in the code. It is a separate SDMX dimension — the SEX dimension — with values F, M, _T (total). You select a slice at query time:

get_data(indicator='CME_MRY0T4', sex='F')   # under-5 mortality, girls
get_data(indicator='CME_MRY0T4', sex='M')   # under-5 mortality, boys
get_data(indicator='CME_MRY0T4', sex='_T')  # under-5 mortality, total

The differentiator.py:_SUFFIX_MEANINGS table lists F, M, _T, MF as sex-token meanings; those entries describe the values of the SEX dimension, not a suffix you append to an arbitrary code. Appending _F to a code that does not already carry it (e.g. inventing NT_ANT_HAZ_NE2_F) will not resolve — the catalog does not contain such codes.

Age / wealth / residence disaggregation tokens

Disaggregation tokens appear either embedded in the code (when they are part of the canonical definition, e.g. PT_F_20-24_MRD_U18) or applied at query time via get_data() filters. The tokens below are the same in both places.

Age bands

Age is encoded as LOW-HIGH (inclusive) in the embedded form, or as a bound token at the end of the code.

Token	Meaning
15-19, 20-24, 15-49	Inclusive age band in years
Y0	Under 1 year (neonatal / infant variants)
Y0T4	0 through 4 years inclusive (under-5)
Y1T4	1 through 4 years inclusive (childhood, post-infant)
U5, U15, U18	"Under" threshold — strictly below the named age
ADOL	Adolescent (10–19, occasionally 10–24)

Wealth quintile (query-time filter)

Token	Meaning
Q1	Lowest quintile (poorest 20%)
Q2, Q3, Q4	Middle quintiles
Q5	Highest quintile (richest 20%)
B20 / B40	Bottom 20% / bottom 40%
T20	Top 20%

Residence (query-time filter)

Token	Meaning
_T	Total
U	Urban
R	Rural

Anthropometric Z-score thresholds

These appear in the NT_ANT_* family and need their own table because the convention is non-obvious:

Token	Meaning
NE2	Below -2 SD ("negative end, 2 SD") — moderate-or-severe form
NE3	Below -3 SD — severe form
NE2_T_NE3	Between -3 SD and -2 SD — moderate-only form
PO2	Above +2 SD — overweight side
HAZ / WAZ / WHZ / BAZ	Height-for-age / Weight-for-age / Weight-for-height / BMI-for-age Z-scores

Derived metrics: TRGT_ / _ARR_ / _PRJ

Three special grammars flag values that are not observations but transformations of them. These are the cases where v1.1.1's query-aware CURATED_PREFERRED scoring matters most. Note that ARR is a middle-segment token (e.g. CME_ARR_U5MR, CME_ARR_SBR), not a trailing suffix.

Pattern	Meaning	Example
TRGT_<year>_<indicator>	Country-set target value for the named indicator at the named horizon year. TRGT_2030_IM_DTP3 is the country's 2030 target for DTP3 coverage, not the observed value.	TRGT_2030_IM_DTP3
*_ARR_*	Annual Rate of Reduction — annualised percentage change derived from the underlying series; appears as a middle-segment token	CME_ARR_U5MR, CME_ARR_SBR
*_PRJ / *_PRJ_*	Projected / forecast value rather than observed	PT_F_20-24_MRD_U15_PRJ

v1.1.1 query-aware scoring (commit 7112e1d): the MCP only surfaces TRGT_* codes when your natural-language query mentions target, goal, objective, or a horizon year. A bare "DTP3 coverage in Brazil" question will resolve to the observation series; "Brazil's 2030 DTP3 target" will resolve to TRGT_2030_IM_DTP3. This is implemented as a hint field on CURATED_PREFERRED entries in differentiator.py, not as a hard exclusion — the target code is still discoverable via direct lookup, just demoted in resolver ranking unless the query signals intent.

The same query-aware demotion applies to _MOD (modelled) variants: queries mentioning survey, raw, or observed prefer the un-suffixed code; queries mentioning modelled, estimate, joint estimation prefer _MOD.

Education levels

In the ED_* family, ISCED levels are abbreviated L1 / L2 / L3:

Token	ISCED level	Conventional name
L1	ISCED 1	Primary education
L2	ISCED 2	Lower-secondary education
L3	ISCED 3	Upper-secondary education

Examples: ED_ANAR_L1 (adjusted net attendance rate, primary), ED_ANAR_L2 (lower-secondary), ED_CR_L1 (completion rate, primary). Where a code stops at L1 it is primary-only; where two levels are reported jointly the codes are listed separately rather than concatenated.

Scope caveat. The L<n> = ISCED <n> mapping holds only inside the ED_* family. Outside ED_*, L<n> may encode a non-ISCED level — for example PV_CHLD_MPI_L1 and PV_CHLD_MPI_L2 use L1 / L2 to mean severe and moderate multidimensional-poverty deprivation respectively. Some ED_* codes also use the two-digit form L01 / L02 to encode early-childhood or pre-primary levels that sit below ISCED 1. Always check the indicator's name before assuming L<n> means primary / lower-secondary / upper-secondary.

Where this is encoded in the MCP

The conventions documented above are not folklore — they are encoded in the MCP source and can be audited directly:

• src/unicefstats_mcp/differentiator.py is the canonical reference for segment-level meaning. The _SUFFIX_MEANINGS table maps every recognised trailing token to a human-readable gloss; explain_difference() walks two codes side-by-side and labels each diverging segment; the CURATED_PREFERRED table carries per-indicator dimension_hint strings that drive the v1.1.1 query-aware scoring.
• src/unicefstats_mcp/indicator_resolver.py maps natural-language phrases to canonical codes. _SYNONYMS covers the routine cases ("stunting", "under-5 mortality", "child marriage"); _AMBIGUOUS flags phrases that legitimately map to more than one code and require user disambiguation; _DISAMBIGUATION_TIPS carries the short hints surfaced in the assistant_guidance envelope field added in v1.1.0.
• unicef://glossary MCP resource — clients that load resources at session start get the disaggregation-code and indicator-prefix legend without having to parse this README.

When the resolver picks a code, the chain is: natural-language query → indicator_resolver lookup → if ambiguous, _AMBIGUOUS hit fires the v1.0.0 ambiguity_flag + candidate list → if a CURATED_PREFERRED entry matches, the dimension_hint re-ranks candidates → the chosen code is annotated by differentiator.py for the assistant_guidance field. Every step is inspectable in the source; nothing in this section is heuristic on the LLM side.

Demo

Step 1: Search for indicators

>>> search_indicators("stunting", limit=3)

{
  "query": "stunting",
  "total_matches": 11,
  "showing": 3,
  "results": [
    {"code": "FD_STUNTING", "name": "Moderate and severe stunting (Functional difficulties)"},
    {"code": "NT_ANT_HAZ_NE2", "name": "Height-for-age <-2 SD (stunting)"},
    {"code": "NT_ANT_HAZ_NE3", "name": "Height-for-age <-3 SD (severe stunting)"}
  ],
  "tip": "Use get_indicator_info('FD_STUNTING') for full details including available disaggregations."
}

Step 2: Get indicator metadata

>>> get_indicator_info("CME_MRY0T4")

{
  "code": "CME_MRY0T4",
  "name": "Under-five mortality rate",
  "description": "Probability of dying between birth and exactly 5 years of age, expressed per 1,000 live births",
  "dataflow": "GLOBAL_DATAFLOW",
  "sdmx_api": "https://sdmx.data.unicef.org/ws/public/sdmxapi/rest/data/UNICEF,GLOBAL_DATAFLOW,1.0/.CME_MRY0T4?format=csv",
  "disaggregation_filters": {
    "sex": ["_T (Total)", "M (Male)", "F (Female)"],
    "wealth_quintile": ["Q1 (Lowest)", "Q2", "Q3", "Q4", "Q5 (Highest)"],
    "residence": ["_T (Total)", "U (Urban)", "R (Rural)"]
  }
}

Step 3: Check temporal coverage

>>> get_temporal_coverage("CME_MRY0T4")

{
  "code": "CME_MRY0T4",
  "start_year": 1931,
  "end_year": 2024,
  "latest_year": 2024,
  "countries_with_data": 249,
  "note": "Not all countries have data for all years. Coverage varies by country."
}

Step 4: Fetch data

>>> get_data("CME_MRY0T4", ["BRA", "IND", "NGA"], start_year=2018, end_year=2023)

{
  "indicator": "CME_MRY0T4",
  "countries_requested": ["BRA", "IND", "NGA"],
  "total_rows_available": 18,
  "rows_returned": 18,
  "rows_truncated": false,
  "format": "compact",
  "summary": {
    "value_range": {"min": 14.42, "max": 117.56, "mean": 54.78},
    "year_range": {"earliest": 2018, "latest": 2023},
    "countries_in_result": 3
  },
  "data": [
    {"iso3": "BRA", "country": "Brazil",  "period": 2018, "indicator": "CME_MRY0T4", "value": 15.22},
    {"iso3": "BRA", "country": "Brazil",  "period": 2019, "indicator": "CME_MRY0T4", "value": 15.03},
    {"iso3": "BRA", "country": "Brazil",  "period": 2020, "indicator": "CME_MRY0T4", "value": 14.87},
    {"iso3": "BRA", "country": "Brazil",  "period": 2021, "indicator": "CME_MRY0T4", "value": 14.72},
    {"iso3": "BRA", "country": "Brazil",  "period": 2022, "indicator": "CME_MRY0T4", "value": 14.59},
    {"iso3": "BRA", "country": "Brazil",  "period": 2023, "indicator": "CME_MRY0T4", "value": 14.42},
    {"iso3": "IND", "country": "India",   "period": 2018, "indicator": "CME_MRY0T4", "value": 36.87},
    {"iso3": "IND", "country": "India",   "period": 2019, "indicator": "CME_MRY0T4", "value": 34.86},
    {"iso3": "IND", "country": "India",   "period": 2020, "indicator": "CME_MRY0T4", "value": 32.98},
    {"iso3": "IND", "country": "India",   "period": 2021, "indicator": "CME_MRY0T4", "value": 31.19},
    {"iso3": "IND", "country": "India",   "period": 2022, "indicator": "CME_MRY0T4", "value": 29.53},
    {"iso3": "IND", "country": "India",   "period": 2023, "indicator": "CME_MRY0T4", "value": 27.99},
    {"iso3": "NGA", "country": "Nigeria", "period": 2018, "indicator": "CME_MRY0T4", "value": 117.19},
    {"iso3": "NGA", "country": "Nigeria", "period": 2019, "indicator": "CME_MRY0T4", "value": 117.37},
    {"iso3": "NGA", "country": "Nigeria", "period": 2020, "indicator": "CME_MRY0T4", "value": 117.42},
    {"iso3": "NGA", "country": "Nigeria", "period": 2021, "indicator": "CME_MRY0T4", "value": 117.56},
    {"iso3": "NGA", "country": "Nigeria", "period": 2022, "indicator": "CME_MRY0T4", "value": 117.46},
    {"iso3": "NGA", "country": "Nigeria", "period": 2023, "indicator": "CME_MRY0T4", "value": 116.82}
  ]
}

Key insights an AI assistant would extract from this:

• Brazil: 14.4 per 1,000 — steadily declining, on track for SDG 3.2 target (≤25)
• India: 28.0 per 1,000 — rapid improvement (37→28 in 5 years), recently crossed SDG target
• Nigeria: 117 per 1,000 — essentially flat, 4.7× the SDG target, highest burden

Step 5: Get code template to continue in a script

>>> get_api_reference("r", "unicefData")

{
  "language": "r",
  "install": "install.packages(\"unicefdata\")",
  "import": "library(unicefdata)",
  "function": "unicefData",
  "signature": "unicefData(\n    indicator = NULL,        # character — indicator code(s)\n    countries = NULL,         # character vector — ISO3 codes, NULL = all\n    year = NULL,              # numeric, character (\"2015:2023\"), or vector\n    sex = \"_T\",               # character — \"_T\", \"M\", \"F\"\n    totals = FALSE,           # logical — only return aggregate totals\n    tidy = TRUE,              # logical — standardize column names\n    country_names = TRUE,     # logical — add country name column\n    format = \"long\",          # character — \"long\", \"wide\", \"wide_indicators\"\n    latest = FALSE,           # logical — most recent value per country\n    circa = FALSE,            # logical — closest available year\n    add_metadata = NULL,      # character vector — e.g. c('region', 'income_group')\n    dropna = FALSE,           # logical — drop rows with missing values\n    simplify = FALSE,         # logical — minimal columns\n    mrv = NULL,               # integer — most recent N values per country\n    raw = FALSE,              # logical — all disaggregations, no filtering\n)",
  "returns": "tibble with columns: indicator_code, iso3, country, period, value, sex, age, wealth_quintile, residence, ...",
  "examples": [
    {"description": "Under-5 mortality for Brazil, India, Nigeria (2015–2023)", "code": "df <- unicefData(\"CME_MRY0T4\", countries = c(\"BRA\", \"IND\", \"NGA\"), year = \"2015:2023\")"},
    {"description": "Latest stunting data for all countries", "code": "df <- unicefData(\"NT_ANT_HAZ_NE2\", latest = TRUE)"},
    {"description": "Wide format with region metadata", "code": "df <- unicefData(\"CME_MRY0T4\", format = \"wide\", add_metadata = c(\"region\", \"income_group\"))"}
  ]
}

This lets the AI generate correct R/Python/Stata code using the exact parameter names and syntax — no guessing from training data.

get_data parameters

Parameter	Type	Default	Description
indicator	str	required	Indicator code
countries	list[str]	required	ISO3 codes (max 30)
start_year	int	None	Start of year range
end_year	int	None	End of year range
sex	str	"_T"	"_T" (total), "M" (male), "F" (female)
wealth_quintile	str	None	"Q1"–"Q5", "B20", "B40", "T20"
residence	str	None	"U" (urban), "R" (rural), "_T" (total)
format	str	"compact"	"compact" (5 cols) or "full" (all cols)
limit	int	200	Max rows (1–500)

Response features

• summary: Value range (min/max/mean), year range, country count
• disaggregations_in_data: Which dimensions have non-trivial variation
• total_rows_available vs rows_returned: Pagination metadata
• tip: Contextual guidance for next steps or narrowing results

Prompts

compare_indicators

Pre-built analysis workflow: fetches indicator metadata and data, then produces a structured comparison.

compare_indicators(indicator="CME_MRY0T4", countries="BRA,IND,NGA", start_year="2015", end_year="2023")

write_unicefdata_code

Generate runnable Python, R, or Stata code using the unicefdata package. The AI will call get_api_reference() to get the exact function signatures, then write code matching the user's task.

write_unicefdata_code(
    task="Compare under-5 mortality for Brazil and India, 2015-2023, then plot the trends",
    language="r"
)

This bridges the gap between conversational exploration (via MCP tools) and reproducible analysis scripts (via unicefdata packages).

Benchmark Results

We benchmarked the MCP against a bare LLM (Claude Sonnet 4, no tools) using the EQA metric from Azevedo (2025). 300 queries across 10 indicators, 20 countries, 2 prompt types, and 2 hallucination test categories.

Two benchmark pillars

The repo maintains two empirical scoreboards:

1. 300-query EQA test (10 indicators × 20 countries × 2 prompts × 2 hallucination categories) — the original Azevedo (2025) benchmark used through v1.0.x / v1.1.x. Numbers below labelled "v0.7.3 + fixes".
2. v9 Arm B 1484-cell paired benchmark — larger, more granular, introduced during the v1.5.x curated-defaults cycle. Compares each MCP vintage cell-by-cell against the v1.2.4 Jun 1 baseline. v1.5.5 measured mean EQA 0.749 (+29.1pp, p = 2×10⁻¹⁰⁵).

The two are scored under different rubrics on different samples; they are complementary, not directly comparable.

Current canonical numbers — 300-query EQA test (v0.7.3 + fixes, May 2026)

The numbers below are the current canonical scoreboard. They reflect (a) four engineering fixes in the v0.7.3 cycle (see CHANGELOG) and (b) a scoring correction from the v1.4 extractor that respects refusal language. Both samples (mcp060: 40 countries; mcp073: disjoint 20-country validation sample) score under the same v1.4 rules.

Metric	LLM alone (no tools)	LLM + MCP (v0.7.3 + fixes)	Sample
POS EQA mean	0.121	0.891	mcp060 (40 ctry)
POS EQA mean	0.121	0.909	mcp073 (20 disjoint ctry)
hall_b combined (T1+T2)	2.50% (hall_a)	1.00%	mcp060
hall_b combined (T1+T2)	2.50% (hall_a)	2.25%	mcp073
MCP makes model safer (hall_b < hall_a)	—	Yes — both samples	both

v0.7.3 + fixes is the first version where MCP demonstrably makes the model safer than the no-tools baseline on absent-data queries. Through v0.7.2, hall_b ≥ hall_a — the safety layer was reducing magnitude but not direction. The four fixes that flipped the property:

1. server.py:_seed_data_frontier_cache — monotonic max instead of unconditional overwrite (a probe-induced regression of the cached frontier was telling the LLM that current data was unavailable).
2. server.py:get_data exception handler — unicefdata cascade exhaustion reclassified as no_data (not error), so the LLM treats it as authoritative absence rather than tool failure.
3. benchmark_eqa_batch.py — persist tool result_str on state.tool_calls so the v1.4 extractor can see refusals.
4. benchmark_eqa_batch.py — refusal-respect parity with the sync runner.

Canonical scoreboard: see the [Unreleased] §Fixed block at the top of CHANGELOG.md for the full cross-version table, including the four post-fix corrections and the mcp073 second-sample validation. Full per-run write-ups live in internal/v0_7_3_validation.md and internal/v0_7_3_second_sample_validation.md in the dev repo (jpazvd/unicefstats-mcp-dev, dev-only and not synced to this public mirror).

Historical: v0.3.0 (n=600, 2025) and v0.7.2 (n=500 same-day, 2026-05-08)

The original v0.3.0 benchmark reported POS EQA 0.147 → 0.990 (6.7×) and T2 hallucination 11% → 37%. Two corrections since:

• The "37%" headline was substantially a v1.3 extractor scoring artefact: the extractor counted any numeric value mentioned in the response as a "claim," including values quoted from no_data tool results inside an explicit refusal. The v1.4 extractor (_detect_refusal) reclassifies those as appropriate refusals. We did not rescore the v0.3.0 parquets under v1.4 (they're archived); the v1.4-equivalent of "37%" is unknown but substantially lower.
• The v0.7.2 reproduction (n=500, 2026-05-08) under v1.3 scoring reported POS EQA 0.897 and combined T1+T2 hallucination 13%. Under v1.4 scoring the same parquets report POS EQA 0.793 and hall_b 3.75%.

The accuracy headline (~7× lift) has held up across every rescoring. The hallucination headline required both a scoring fix (v1.4 extractor) and a server fix (v0.7.3 cache + cascade fixes) before MCP actually reduced hallucination below the no-tools baseline.

EQA decomposition (baseline_latest prompt)

Component	LLM alone	LLM + MCP	Gain
ER (extraction rate)	0.50	1.00	+0.50
YA (year accuracy)	0.24	0.99	+0.75
VA (value accuracy)	0.37	1.00	+0.63
EQA = ER × YA × VA	0.147	0.990	+0.843

Key findings

1. All 10 indicators at EQA >= 0.95 with MCP, replicated across 40 countries (R1 + R2 with zero overlap). 7 of 10 achieve perfect EQA = 1.000.

2. Year accuracy is the bare LLM's biggest weakness (YA = 0.24). It cites 2021-2022 as "latest" when IGME 2024 estimates exist. The MCP queries the API and returns the actual latest year.

3. The direct prompt shows larger MCP gain (+0.722 vs +0.613) because it eliminates YA and isolates pure retrieval accuracy.

4. T2 hallucination (~37%) is inflated by ground truth misclassification: the SDMX API has IGME mortality data for micro-states that the ground truth pipeline missed. After correction: MCP ~10%, LLM alone ~5%. The remaining hallucination is driven by the confidence effect — Claude overrides tool errors when it has strong domain priors.

5. The confidence effect: When the MCP tool returns "no data" but the LLM has strong domain priors (e.g., child mortality for well-known countries), it overrides the tool and fabricates anyway. This is a fundamental LLM behavior, not MCP-specific.

3-way comparison (vs sdmx-mcp)

Metric	LLM alone	unicefstats-mcp (v0.7.3 + fixes)	sdmx-mcp
EQA (POS)	0.121	0.891	0.074
hall_b combined (T1+T2)	hall_a 2.50%	1.00% (mcp060) / 2.25% (mcp073)	0%
MCP safer than no-tools?	—	Yes	Yes (zero by construction)
Cost per query	~$0.003	~$0.04	$0.087
Avg latency	~5s	~10s	60s

sdmx-mcp's raw SDMX-JSON output is hard for LLMs to parse (VA ≈ 0.11), but its anti-hallucination guardrails are highly effective (0% fabrication). See Relationship to sdmx-mcp for details.

v9 Arm B paired benchmark (1484 cells, Jun 2026)

The v1.5.x cycle introduced a second, larger benchmark — v9 Arm B, 1484 cells, master_seed=42 — that compares each MCP vintage cell-by-cell against a fixed v1.2.4 baseline. Unlike the 300-query EQA test (which scores indicator + year + value extraction quality), v9 Arm B measures paired ΔEQA so it can isolate the contribution of each vintage's changes.

vintage	date	mean EQA	Δ vs v1.2.4	p-value
v1.2.4	Jun 1 2026	0.458	—	—
v1.4.0	Jun 4 2026	0.481	+2.3pp	0.0003
v1.5.1	Jun 6 2026	0.681	+22.3pp	7×10⁻⁷⁶
v1.5.5	Jun 7 2026	0.749	+29.1pp	2×10⁻¹⁰⁵

• 4 of 5 decision-rule gates PASS for v1.5.5
• 430 FIRE_RECOVERABLE cells lift at +0.97 EQA each
• Lost:rescued ratio 0.03 (vs v1.4.0's 0.41)
• Cascade-attributable lift on FIRE_ALTERED: +0.80 [+0.77, +0.83]

This benchmark is what validates the +29.1pp claim. The 300-query EQA test above still applies and remains the canonical reference for hallucination-rate measurement.

Full analysis, per-indicator decomposition, and methodology: examples/RESULTS.md

Benchmark data (parquet with full LLM responses): examples/results/

Benchmark design rationale: examples/DESIGN_ISSUES.md

Reproducing the benchmark

# Build ground truth from UNICEF SDMX API
python examples/00_build_ground_truth.py

# Run 200-query benchmark (requires ANTHROPIC_API_KEY, ~$6)
python examples/benchmark_eqa.py

# Add 100 direct-prompt queries to existing run (~$3)
python examples/01_run_direct_supplement.py

Citation

This benchmark uses the EQA metric from:

Azevedo, J.P. (2025). "AI Reliability for Official Statistics: Benchmarking Large Language Models with the UNICEF Data Warehouse." UNICEF Chief Statistician Office. github.com/jpazvd/unicef-sdg-llm-benchmark-dev

Deployment

Local (stdio)

unicefstats-mcp

Remote (SSE)

unicefstats-mcp --transport sse --port 8000

Docker

docker build -t unicefstats-mcp .
docker run -p 8000:8000 unicefstats-mcp

Environment variables

The MCP runs with no required configuration. Two opt-in environment variables (v1.5.5+) help large-batch / benchmark use survive UNICEF SDMX's WAF / per-IP rate-limiter:

variable	default	effect when set
UNICEFSTATS_SDMX_THROTTLE_MS	0 (off)	Minimum inter-call delay (ms) between SDMX unicefData() calls in this process. Recommended 200–500 for batch use so the request rate stays below the empirically-observed ~50-100 calls/min WAF trigger threshold.
UNICEFSTATS_SDMX_RETRY_403	unset	When set to 1 / true / yes / on, retries SDMXForbiddenError (HTTP 403) with exponential backoff (30s, 60s, 120s; max 3 retries) instead of failing immediately. Lets a long-running batch survive transient WAF bursts.

For normal interactive MCP server use (single-query conversational tasks via Claude / Cursor / etc.), leave both unset — defaults preserve fast-fail behaviour.

For benchmark / batch use (1000+ sequential queries from one IP):

export UNICEFSTATS_SDMX_THROTTLE_MS=300
export UNICEFSTATS_SDMX_RETRY_403=1

Development

pip install -e ".[dev]"
pytest tests/ -v
ruff check src/ tests/
mypy src/unicefstats_mcp/

Contributing

Contributions are welcome.

Ways to contribute

• Bug reports: Open an issue with steps to reproduce
• Feature requests: Suggest new tools, indicators, or output formats via issues
• Code: Fork, branch, submit a PR — see development setup below
• Benchmark: Run the EQA benchmark on different models and share results
• Documentation: Improve examples, fix typos, add use cases

Development setup

git clone https://github.com/jpazvd/unicefstats-mcp.git
cd unicefstats-mcp
pip install -e ".[dev,benchmark]"
pytest tests/ -v
ruff check src/ tests/
mypy src/unicefstats_mcp/

Pull request guidelines

1. One concern per PR — keep changes focused and reviewable
2. Include tests for new tools or bug fixes
3. Run the linter (ruff check) and type checker (mypy) before submitting
4. Update the README if you change tool signatures or add new features
5. Do not commit API keys or benchmark result parquets larger than 500KB

Priority areas

See the audit findings for known issues. High-impact areas:

• MNCH dataflow bug: MNCH_CSEC and MNCH_BIRTH18 return 0 EQA due to a dataflow resolution issue in the unicefdata package
• T2 hallucination reduction: Further reduce fabrication when API returns no results (currently ~10%; see Limitations)

Limitations and Hallucination Risks

Data limitations

• Coverage is uneven across indicators, countries, and years. Survey-based indicators (nutrition, education, protection) have 3-5 year gaps between data points by design.
• Mortality indicators (CME_*) are modeled estimates from the UN Inter-agency Group (IGME), with uncertainty intervals not surfaced in compact output.
• Not all indicators support all disaggregation dimensions; get_indicator_info() lists what's available per indicator.
• get_data() caps at 500 rows per call.

Hallucination risks

Benchmark testing across multiple country samples (v0.7.3 + fixes, May 2026):

Type	Description	Rate (LLM alone, hall_a)	Rate (LLM + MCP, hall_b)	Notes
T1 (gap-year)	LLM cites a value for a year when the indicator has data but not for that specific year	~1.0%	0.00% (mcp060) / 0.50% (mcp073)	Below the no-tools rate
T2 (forward-of-frontier)	LLM fabricates a value for a year beyond the data frontier	~3.5%	2.00% (mcp060) / 4.00% (mcp073)	Below the no-tools rate
Combined	T1 + T2	hall_a 2.50%	1.00% (mcp060) / 2.25% (mcp073)	hall_b < hall_a — MCP makes safer

v0.7.3 + fixes is the first release where MCP makes the model safer than the no-tools baseline. Through v0.7.2 (v1.4 scoring), hall_b ≥ hall_a — the safety layer was reducing magnitude relative to a no-safety-layer baseline but never enough to put MCP under the no-tools floor.

What changed:

1. Cache contamination in _seed_data_frontier_cache — a probe routine was overwriting the cached max-year for an indicator with whatever year happened to come back, sometimes lower than the cached value. The LLM was being told frontiers were 2018 for indicators whose real frontier was 2023, then answering about 2023 from parametric memory. Fix: monotonic max() only.
2. unicefdata cascade as no_data, not error — the underlying wrapper's fallback-dataflow exhaustion was leaking as a tool exception, which the LLM read as "tool failed, fall back to my own knowledge." Now classified as a clean no_data signal that the safety layer converts into "do not estimate." Filed unicefdata-dev#74 for an upstream fix.
3. v1.4 extractor (_detect_refusal) — corrected the long-standing scoring artefact in which any numeric value in a response was counted as a "claim," including values the LLM was quoting from no_data tool results inside an explicit refusal. This dropped hall_b in the v0.7.3 PRE-FIX rescoring from ~37% to 2.25% — most of the historical "MCP-makes-it-worse" finding was extractor, not behaviour.
4. Batch runner parity — result_str persistence and refusal-respect in the async batch runner.

This finding still leaves room for the broader tool-augmented LLM literature on the structural cost of giving models an answer-producing pathway:

• The Reasoning Trap: How Enhancing LLM Reasoning Amplifies Tool Hallucination (ICLR 2025) — shows the relationship is causal: as models get better at tool use, tool hallucination rises proportionally with capability.
• Reducing Tool Hallucination via Reliability Alignment (Cao et al., 2024, arXiv:2412.04141) — formalises the failure as tool-selection errors (wrong tool, failed refusal) and tool-usage errors (fabricated parameters).
• ReDeEP: Detecting Hallucination in Retrieval-Augmented Generation via Mechanistic Interpretability (Sun et al., 2024) — shows mechanistically that an LLM's parametric knowledge can override retrieved context inside the residual stream.

These results show the structural tendency is real; the v0.7.3 + fixes result shows it can be reversed for a specific data domain through (a) safety-layer architecture, (b) server-side discipline (no stale frontier cache, no leaking of no-data as tool errors), and (c) honest scoring.

The takeaway for users:

1. Load the unicef://system-prompt and unicef://context resources at session start (handles forward-of-frontier fabrication).
2. Treat MCP results as best-effort retrieval, not infallible truth — verify load-bearing values against the UNICEF Data Warehouse before citing.
3. Prefer queries with explicit years ("under-five mortality in Nigeria in 2023") over open-ended ones ("the latest under-five mortality in Nigeria") — the former triggers refusal more reliably when data is absent.
4. The 1.00% / 2.25% residuals were measured on Sonnet 4 only. Cross-model generalisation is the next benchmark.

Full benchmark methodology: examples/RESULTS.md

Provenance and Ownership

All data served by this MCP originates from the UNICEF Data Warehouse, accessed live via the public SDMX REST API. No observation data is stored or cached — every get_data() call results in a live SDMX request. The indicator and country registries are cached in memory at first access for performance; these are catalogue metadata, not statistical values. The MCP reformats output for LLM consumption but does not alter values.

All releases are published from GitHub Actions using PyPI Trusted Publishing (OIDC). No long-lived API tokens exist. Release provenance is verifiable via PyPI attestations.

For full details on data origin, ownership, distribution pipeline, and interpretation caveats, see PROVENANCE.md.

How to Verify This MCP

Check	How
Source	Repository is jpazvd/unicefstats-mcp on GitHub
Package	pip show unicefstats-mcp — verify Home-page points to the canonical repo
Version	python -c "import unicefstats_mcp; print(unicefstats_mcp.__version__)" — compare with server.json and PyPI
Provenance	PyPI attestations link each release to a GitHub Actions workflow
Runtime	Call get_server_metadata() — returns canonical name, version, publisher, and data source

License

MIT