How do I install the ai.nullary/nullary MCP server?

ai.nullary/nullary is a hosted endpoint at https://mcp.nullary.ai/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

ai.nullary/nullary

REMOTE · MCP.NULLARY.AI · SCANNED SEP 20

Negative results intelligence for drug discovery — query measured failures via MCP.

Available components

remote · mcp.nullary.ai 85

0 this week 85 85 Trust /100

Trust breakdown (7 categories)

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →

Endpoint Security80

The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. See how to fix → View diagnostics → Partial
HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail

Transport & Reachability100

Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass

Schema Quality & AI Usability62

AI-judged instruction clarity (good).Pass
Context-footprint check failed: tool/resource definitions use about 4999 tokens (~142/item across 35 items; 35 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
Usage-examples check failed: none of the tools include examples. See how to fix → Fail

Stability & Change Management100

No destabilizing schema changes in the last 30 days.Pass

Tool Coverage100

100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
100% of tool parameters carry a description.Pass
Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass

Tool Safety100

No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
We read all 35 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
An AI judge read all 36 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass

Capabilities100

Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass

Changelog

Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.

26 Aug 26 +1
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
25 Aug 26 0
- Stability: 0.97 → pass security
24 Aug 26 +1

No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.
11 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
31 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
27 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
26 Jul 26 0

First indexed and scored.

Show 5 earlier entries Hide earlier entries

Diagnostics

Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.

Captured 20 Sept 2026 · Probed https://mcp.nullary.ai/mcp

TLS valid

Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .

Subject	Issuer	Valid from	Valid until	Key	Signature	Serial
CN=mcp.nullary.ai	CN=YR1,O=Let's Encrypt,C=US	26 Jul 2026	24 Oct 2026	RSA 2048	SHA256-RSA	61bd13aee9c84eeb7ca21e7e9e0eb3a6139
SANs: mcp.nullary.ai
CN=YR1,O=Let's Encrypt,C=US (CA)	CN=Root YR,O=ISRG,C=US	3 Sept 2025	2 Sept 2028	RSA 2048	SHA256-RSA	a20253f15f2691c05dc1ce13b9bcca4e
CN=Root YR,O=ISRG,C=US (CA)	CN=ISRG Root X1,O=Internet Security Research Group,C=US	13 May 2026	2 Sept 2032	RSA 4096	SHA256-RSA	f24b6d17f9d9ad7cb1c9fea78782699f

Background: What to check on a remote MCP endpoint →

DNSSEC insecure

Validation of mcp.nullary.ai. — Not signed

Zone	DS	Keys	Algorithms	Outcome
.	trust_anchor	20326, 38696	8, 8	Verified
ai.	present	3799	8	Verified
nullary.ai.	absent			Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation

Authentication No authorisation required

The endpoint answered without asking for a token. Anyone who knows the URL can reach it.

Result	No authorisation required
HTTP status	200

Header	Value
strict-transport-security	max-age=63072000

Background: How OAuth 2.1 works in the 2026 MCP spec →

Transports 2 probes

Transport	URL	Outcome	Status	Location
streamable-http	https://mcp.nullary.ai/mcp	Verified	200
http (plaintext)	http://mcp.nullary.ai/mcp	HTTPS enforced	308	https://mcp.nullary.ai/mcp

MCP tools · 35 exposed · ~4,956 tokens

The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →

Tool Tokens

get_compound ~189

A compound (structure, name, max clinical phase) + its full negative profile across modalities/sources.

Input Output Examples

Name	Type	Req	Description
chembl_id	string	–	ChEMBL molecule ID, e.g. CHEMBL941.
inchi_key	string	–	Compound InChIKey (provide one of inchi_key, chembl_id, or pubchem_cid).
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
pubchem_cid	integer	–	PubChem Compound ID (CID).
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
compound	object	–	Identity: pref_name, chembl_id, inchi_key, max_phase.
findings	array	–	Every negative finding for this molecule.
query_metadata	object	yes	Echo of the resolved query.
returned_count	integer	–	–

No examples provided.

get_coverage ~25

Per-modality and per-source coverage stats (honest Phase-1 numbers).

Input Output Examples

Input schema present but exposes no named parameters.

Name	Type	Req	Description
by_modality	array	–	Per-modality finding counts.
by_source_type	array	–	Per-source finding counts.
curated_total	integer	–	–
query_metadata	object	yes	Echo of the resolved query.
total	integer	–	–

No examples provided.

get_finding_provenance ~32

Full provenance + detail for a single finding by id.

Input Output Examples

Name	Type	Req	Description
id	string	yes	finding UUID

Name	Type	Req	Description
finding	object	–	The finding with source, DOI/PMID, assay context, and confidence tier.
query_metadata	object	yes	Echo of the resolved query.

No examples provided.

get_model_card ~79

Per-target Layer-1 model card: training counts and held-out scaffold-split metrics (ROC-AUC, PR-AUC, Brier, calibration). Accepts a gene symbol (e.g. EGFR) or UniProt accession (e.g. P00533).

Input Output Examples

Name	Type	Req	Description
target	string	yes	gene symbol or UniProt accession (required)

Name	Type	Req	Description
query_metadata	object	yes	Echo of the resolved query.

No examples provided.

get_target_landscape ~91

Target 'graveyard' / exhaustion index: how many distinct compounds/agents have been tried against a target and failed, broken down by modality and outcome. Answers 'how picked-over is this target?'. Accepts a gene symbol (e.g. EGFR) or a UniProt accession (e.g. P00533).

Input Output Examples

Name	Type	Req	Description
target	string	yes	gene symbol or UniProt accession (required)

Name	Type	Req	Description
by_modality	array	–	Per-modality failed-agent counts.
by_outcome	array	–	Per-outcome counts.
query_metadata	object	yes	Echo of the resolved query.
summary	string	–	One-line natural-language summary.

No examples provided.

list_models ~39

Summary of the Layer-1 inactivity-scoring model registry: how many per-target models, split by family, and median scaffold-split ROC-AUC.

Input Output Examples

Input schema present but exposes no named parameters.

Name	Type	Req	Description
query_metadata	object	yes	Echo of the resolved query.

No examples provided.

list_top_targets ~91

Coverage browse: the most heavily-pursued ('graveyard') targets, ranked by recorded negative findings. Optional family filter (kinase, gpcr, protease, nuclear_receptor, ion_channel, transporter, phosphatase, other).

Input Output Examples

Name	Type	Req	Description
family	string	–	target family filter (optional)
limit	integer	–	Maximum number of findings to return (1–100, default 25).

Name	Type	Req	Description
query_metadata	object	yes	Echo of the resolved query.

No examples provided.

search_adc_linker_failures ~161

ADC failures attributed to linker chemistry.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_admet_failures ~160

Small-molecule ADMET failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_admet_failures_all_modalities ~163

ADMET failures across ALL modalities.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_ancestry_specific_failures ~164

Ancestry-specific CRISPR failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_bispecific_format_failures ~162

Bispecific format/engineering failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_developability_failures ~160

Antibody developability failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_drug_drug_interaction_failures ~150

Drug-drug interaction failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_adcs ~160

ADCs that failed at any stage.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_bispecifics ~163

Bispecifics that failed at any stage.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_clinical_antibodies ~163

Discontinued/terminated clinical antibodies.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_essentiality_screens ~164

Non-dependency / failed essentiality screens.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_guides ~161

Failed/ineffective CRISPR guides.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_oligonucleotides ~168

ASOs/siRNAs that failed engagement/developability.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_peptide_therapeutics ~161

Failed peptide therapeutics.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_protacs ~167

PROTACs that failed degradation/ternary/permeability.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_replications ~158

Findings that failed to replicate.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_selectivity ~159

Small molecules that failed selectivity.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_failed_vaccines ~155

Failed/terminated vaccines (by pathogen/indication).

Input Output Examples

Name	Type	Req	Description
indication	string	–	disease/indication
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_inactive_compounds ~162

Inactive small-molecule compound-target pairs.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_indication_history ~120

ALL failed approaches for an indication across every modality.

Input Output Examples

Name	Type	Req	Description
indication	string	yes	indication (required)
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_mechanism_failures ~165

Approaches that failed for a mechanism (by target).

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_oligo_delivery_failures ~162

Oligonucleotide delivery failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_pathogen_history ~121

Vaccine + antimicrobial + antibody failures for a pathogen.

Input Output Examples

Name	Type	Req	Description
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
pathogen	string	yes	pathogen name (required)
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_peptide_stability_issues ~163

Peptide stability/half-life failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_protac_e3_issues ~170

PROTAC E3-ligase recruitment / ternary failures.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_safety_failures ~161

Clinical/preclinical safety failures across modalities.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_target_history ~124

ALL failed approaches against a target across every modality.

Input Output Examples

Name	Type	Req	Description
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
target	string	yes	UniProt accession or gene symbol (required)
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

search_vaccine_immunogenicity_failures ~163

Failed vaccine immunogen designs.

Input Output Examples

Name	Type	Req	Description
compound	string	–	compound name, ChEMBL ID, or InChIKey
limit	integer	–	Maximum number of findings to return (1–100, default 25).
offset	integer	–	Number of findings to skip before this page, for pagination (default 0).
outcome	string	–	outcome filter (inactive, failed_safety, terminated, …)
target	string	–	UniProt accession or gene symbol
tier	string	–	Confidence tier. 'curated' (default) returns the credible layer; 'all' also includes high-volume screening-grade rows (PubChem HTS inactives, CRISPR non-essential tails).

Name	Type	Req	Description
coverage_note	string	–	Honest coverage caveat for thin Phase-1 modalities (present only when relevant).
findings	array	–	Matching negative findings (same shape as the REST /findings endpoint).
has_more	boolean	–	True when more results exist beyond this page.
query_metadata	object	yes	Echo of the resolved query — tool, limit, offset, and any applied presets.
returned_count	integer	–	Findings returned in this page.

No examples provided.

Common questions

What is the ai.nullary/nullary MCP server?

ai.nullary/nullary is an MCP server listed in the public MCP registry as ai.nullary/nullary. Negative results intelligence for drug discovery, query measured failures via MCP. This page covers its hosted endpoint (https://mcp.nullary.ai/mcp).

Is the ai.nullary/nullary MCP server safe to use?

ai.nullary/nullary scores 85 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

What tools does the ai.nullary/nullary MCP server expose?

ai.nullary/nullary exposes 35 tools: search_inactive_compounds, search_failed_selectivity, search_admet_failures, search_failed_guides, search_failed_essentiality_screens, and 30 more. Their descriptions and schemas cost roughly 4,956 tokens of context every time the server is loaded.

Does the ai.nullary/nullary MCP server require authentication?

No. We connected to ai.nullary/nullary without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

Is the ai.nullary/nullary MCP server still maintained?

ai.nullary/nullary is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

On this page

Handy links

Scoring key

80+ high trust
60–79 medium
below 60 low

How we score

Badge

Put this score in your README. The image is served from a stable URL, updates when the score does, and links back to the evidence on this page. It shows nothing that is not already published here.

Score Verified Plain

The two-cell badge: our name, and this channel's current score out of 100.

Markdown

 [![VerifyMCP trust score for ai.nullary/nullary](https://verifymcp.io/badge/ai-nullary-nullary/mcp.svg)](https://verifymcp.io/servers/ai-nullary-nullary/mcp)

HTML

 <a href="https://verifymcp.io/servers/ai-nullary-nullary/mcp"><img src="https://verifymcp.io/badge/ai-nullary-nullary/mcp.svg" alt="VerifyMCP trust score for ai.nullary/nullary" height="20"></a>

A single cell stating that the server is listed here. Carries no number.

Markdown

 [![VerifyMCP trust score for ai.nullary/nullary](https://verifymcp.io/badge/ai-nullary-nullary/mcp.svg?variant=verified)](https://verifymcp.io/servers/ai-nullary-nullary/mcp)

HTML

 <a href="https://verifymcp.io/servers/ai-nullary-nullary/mcp"><img src="https://verifymcp.io/badge/ai-nullary-nullary/mcp.svg?variant=verified" alt="VerifyMCP trust score for ai.nullary/nullary" height="20"></a>

The score alone, tier-coloured, for a badge row that is already crowded.

Markdown

 [![VerifyMCP trust score for ai.nullary/nullary](https://verifymcp.io/badge/ai-nullary-nullary/mcp.svg?variant=plain)](https://verifymcp.io/servers/ai-nullary-nullary/mcp)

HTML

 <a href="https://verifymcp.io/servers/ai-nullary-nullary/mcp"><img src="https://verifymcp.io/badge/ai-nullary-nullary/mcp.svg?variant=plain" alt="VerifyMCP trust score for ai.nullary/nullary" height="20"></a>

Score history · last 30 days

22 Aug 20 Sept

Trust score by day, last 30 days
Day	Score
22 Aug	83
23 Aug	83
24 Aug	84
25 Aug	84
26 Aug	85
27 Aug	85
28 Aug	85
29 Aug	85
30 Aug	85
31 Aug	85
1 Sept	85
2 Sept	85
3 Sept	85
4 Sept	85
5 Sept	85
6 Sept	85
7 Sept	85
8 Sept	85
9 Sept	85
10 Sept	85
11 Sept	85
12 Sept	85
13 Sept	85
14 Sept	85
15 Sept	85
16 Sept	85
17 Sept	85
18 Sept	85
19 Sept	85
20 Sept	85