uniprot-mcp-server

uniprot-mcp-server: search proteins

uniprot_search_proteins

Read-onlyIdempotent

Search UniProtKB and return curated protein records. Pass text_search for a plain-language query (the 80% case) or query for the full Lucene field syntax (gene:TP53 AND organism_id:9606 AND reviewed:true) — exactly one is required. Reviewed (Swiss-Prot) entries are manually curated; unreviewed (TrEMBL) are computationally predicted and ~30x more numerous, so reviewed defaults to true to avoid drowning in predictions — set it false to search both tiers together (for TrEMBL only, put reviewed:false in query). The organism_id and reviewed filters apply to the whole query. Request facets (e.g. reviewed, model_organism) for server-side count breakdowns. Results page forward with an opaque cursor; UniProtKB has no offset paging. An inactive accession the query matches (merged, demerged, or deleted) comes back in inactive[] with the accessions that replace it, never as a result. This is the discovery entry point — chain results[].accession into uniprot_get_entry for full records, or uniprot_get_sequence for FASTA.

Input Schema

TableJSON Schema

Name	Required	Description
`size`	No	Number of hits per page (max 500). Omit for the server default.
`query`	No	UniProtKB Lucene query with field prefixes — gene, organism_id, keyword (KW-xxxx), go (GO id), reviewed, protein_name, family, length, existence, accession. Example: "gene:BRCA1 AND organism_id:9606 AND reviewed:true". Provide this OR text_search, not both.
`cursor`	No	Opaque forward cursor from this tool for the same exact effective query and filters. Size, fields, and facets may change. Older raw cursors are rejected; restart without cursor. Random access to page N is not supported.
`facets`	No	Comma-separated upstream facet names for count breakdowns, e.g. "reviewed,model_organism,proteins_with". Returns a facets array alongside the hits.
`fields`	No	Comma-separated UniProtKB field names to project, e.g. "accession,gene_names,cc_function". Omit for a sensible default set covering name, gene, organism, length, reviewed, score, and a function snippet.
`reviewed`	No	Restrict to reviewed Swiss-Prot entries. Defaults to true (curated only). false applies no tier filter, returning reviewed and unreviewed TrEMBL entries together; for TrEMBL only, put reviewed:false in query. Ignored when query or text_search already contains a reviewed: clause.
`organism_id`	No	Restrict to an NCBI taxon ID, e.g. 9606 for human. A convenience filter ANDed onto the whole query; resolve names with uniprot_get_taxonomy.
`text_search`	No	Plain-language search across protein names, gene names, and function, e.g. "kinase apoptosis". Provide this OR query, not both.

Output Schema

TableJSON Schema

Name	Required	Description
`error`	No	Present when the call failed. Absent on success.
`cursor`	No	Forward cursor for the next page. Absent on the last page.
`facets`	No	Upstream facet count breakdowns. Present only when facets were requested.
`notice`	No	Guidance when nothing matched — echoes the query and suggests how to broaden.
`results`	No	Matching active protein hits for this page. Inactive accessions are in inactive.
`inactive`	No	Matching accessions that are inactive in UniProtKB (merged, demerged, or deleted) — not proteins to read, but pointers to the accessions that replace them. Present only when the page held any.
`totalResults`	No	Total matches for the query before pagination (from the upstream result count), inactive accessions included.
`effectiveQuery`	No	The query as the server assembled and sent it to UniProtKB.

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedOct 22, 2026

changedInput schema / properties / cursor / description

Previous value: -"Opaque forward-pagination cursor from a prior response. Walk pages with this; random access to page N is not supported."New value: +"Opaque forward cursor from this tool for the same exact effective query and filters. Size, fields, and facets may change. Older raw cursors are rejected; restart without cursor. Random access to page N is not supported."

changedOutput schema / properties / error / properties / data / properties / reason / description

Previous value: -"Machine-readable failure mode. Declared by this tool: `missing_query`: Neither text_search nor query was provided. `conflicting_query`: Both text_search and query were provided. `invalid_query`: The query or text_search has unbalanced parentheses (rejected before any request), or UniProtKB rejected the query, text_search, fields, or facets value — the message names the rejected value. `invalid_cursor`: UniProt could not continue from the cursor (it answered HTTP 500) — the cursor is malformed or truncated. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `missing_query`: Neither text_search nor query was provided. `conflicting_query`: Both text_search and query were provided. `invalid_query`: The query or text_search has unbalanced parentheses (rejected before any request), or UniProtKB rejected the query, text_search, fields, or facets value — the message names the rejected value. `invalid_cursor`: The cursor is malformed, from an older version, belongs to another tool or effective query, or UniProt could not continue from it (HTTP 500). Other values are possible when a failure originates below the handler."

Changed7 schema fields changedOct 14, 2026

changedInput schema / properties / organism_id / description

Previous value: -"Restrict to an NCBI taxon ID, e.g. 9606 for human. A convenience filter ANDed onto the query; resolve names with uniprot_get_taxonomy."New value: +"Restrict to an NCBI taxon ID, e.g. 9606 for human. A convenience filter ANDed onto the whole query; resolve names with uniprot_get_taxonomy."

changedInput schema / properties / reviewed / description

Previous value: -"Restrict to reviewed Swiss-Prot entries. Defaults to true (curated only); set false to include unreviewed TrEMBL. Ignored when query already pins a reviewed: clause."New value: +"Restrict to reviewed Swiss-Prot entries. Defaults to true (curated only). false applies no tier filter, returning reviewed and unreviewed TrEMBL entries together; for TrEMBL only, put reviewed:false in query. Ignored when query or text_search already contains a reviewed: clause."

changedOutput schema / properties / error / properties / data / properties / reason / description

Previous value: -"Machine-readable failure mode. Declared by this tool: `missing_query`: Neither text_search nor query was provided. `conflicting_query`: Both text_search and query were provided. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `missing_query`: Neither text_search nor query was provided. `conflicting_query`: Both text_search and query were provided. `invalid_query`: The query or text_search has unbalanced parentheses (rejected before any request), or UniProtKB rejected the query, text_search, fields, or facets value — the message names the rejected value. `invalid_cursor`: UniProt could not continue from the cursor (it answered HTTP 500) — the cursor is malformed or truncated. Other values are possible when a failure originates below the handler."

changedOutput schema / properties / error / properties / data / properties / reason / examples

Previous value: -[
-  "missing_query",
-  "conflicting_query"
-]New value: +[
+  "missing_query",
+  "conflicting_query",
+  "invalid_query",
+  "invalid_cursor"
+]

addedOutput schema / properties / inactive

Added value: +{
+  "description": "Matching accessions that are inactive in UniProtKB (merged, demerged, or deleted) — not proteins to read, but pointers to the accessions that replace them. Present only when the page held any.",
+  "items": {
+    "additionalProperties": false,
+    "description": "An inactive accession the query matched, with where to go instead.",
+    "properties": {
+      "accession": {
+        "description": "The inactive UniProtKB accession the query matched.",
+        "type": "string"
+      },
+      "deletedReason": {
+        "description": "Why UniProt deleted the entry, when it says. Present on DELETED only.",
+        "type": "string"
+      },
+      "reason": {
+        "description": "UniProt inactiveReasonType: MERGED, DEMERGED, or DELETED. Omitted when UniProt names none.",
+        "type": "string"
+      },
+      "replacedBy": {
+        "description": "Accessions that replace it — the merge target (MERGED) or the demerge products (DEMERGED). Look these up instead.",
+        "items": {
+          "description": "A replacement UniProtKB accession.",
+          "type": "string"
+        },
+        "type": "array"
+      },
+      "uniParcId": {
+        "description": "UniParc ID that still holds the sequence, when UniProt gives one.",
+        "type": "string"
+      }
+    },
+    "required": [
+      "accession"
+    ],
+    "type": "object"
+  },
+  "type": "array"
+}

changedOutput schema / properties / results / description

Previous value: -"Matching protein hits for this page."New value: +"Matching active protein hits for this page. Inactive accessions are in inactive."

changedOutput schema / properties / totalResults / description

Previous value: -"Total matches for the query before pagination (from the upstream result count)."New value: +"Total matches for the query before pagination (from the upstream result count), inactive accessions included."

First observedAug 22, 2026

TDQS

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