NASA SciX MCP Server

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Read-onlyIdempotent

Query NASA SciX astronomical literature with Solr syntax to retrieve papers by author, title, abstract, year, and Boolean filters.

Instructions

Search SciX for astronomical literature. Supports full Solr query syntax including author:"Last, F.", title:keyword, abstract:keyword, year:2020-2023, and Boolean operators (AND, OR, NOT). Pass filter_query to narrow results by facet values obtained from get_facets.

Input Schema

Name	Required	Description	Default
`rows`	No	Number of results to return
`sort`	No	Sort order for results	score desc
`query`	Yes	SciX search query using Solr syntax
`start`	No	Starting offset for pagination
`filter_query`	No	Solr filter queries (fq), each applied independently and ANDed together, e.g. author_facet_hier:"0/Smith, J". Use the `filter` value returned by get_facets.
`response_format`	No	Output format	markdown

Schema Changelog

Changes observed during successful MCP inspections.

Changed14 schema fields changedv1.3.0Oct 21, 2026

addedInput schema / $schema

Added value: +"http://json-schema.org/draft-07/schema#"

addedInput schema / properties / filter_query

Added value: +{
+  "description": "Solr filter queries (fq), each applied independently and ANDed together, e.g. author_facet_hier:\"0/Smith, J\". Use the `filter` value returned by get_facets.",
+  "items": {
+    "maxLength": 500,
+    "minLength": 1,
+    "type": "string"
+  },
+  "maxItems": 20,
+  "type": "array"
+}

changedInput schema / properties / query / description

Previous value: -"Search query using SciX/Solr syntax"New value: +"SciX search query using Solr syntax"

addedInput schema / properties / query / maxLength
```
Added value: +1000
```
addedInput schema / properties / query / minLength
```
Added value: +1
```

changedInput schema / properties / rows / description

Previous value: -"Number of results (1-100, default 10)"New value: +"Number of results to return"

addedInput schema / properties / rows / maximum
```
Added value: +100
```
addedInput schema / properties / rows / minimum
```
Added value: +1
```

changedInput schema / properties / rows / type

Previous value: -"number"New value: +"integer"

changedInput schema / properties / sort / description

Previous value: -"Sort order"New value: +"Sort order for results"

changedInput schema / properties / start / description

Previous value: -"Starting offset for pagination (default 0)"New value: +"Starting offset for pagination"

addedInput schema / properties / start / maximum
```
Added value: +9007199254740991
```
addedInput schema / properties / start / minimum
```
Added value: +0
```

changedInput schema / properties / start / type

Previous value: -"number"New value: +"integer"

First observedv1.0.14May 29, 2026

TDQS

A4.2/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered without the description. The description adds useful context about query syntax support and the facet-filtering workflow, but says nothing about pagination behavior, result counts, or rate limits beyond what annotations and schema provide.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with purpose then query capability then sibling workflow. Every sentence carries information an agent needs; nothing is redundant with the schema or annotations.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, but the description focuses on the one thing the agent most needs to get right: constructing valid queries and filters. Return format, pagination, and sort behavior are delegated to the schema, which documents them adequately, so the definition is nearly complete for a search tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description goes beyond the schema by showing concrete Solr syntax examples (author:"Last, F.", year:2020-2023, Boolean operators) and by tying filter_query to get_facets output, adding real meaning not present in the terse schema descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Search SciX for astronomical literature') and immediately identifies the query dialect, which distinguishes it from sibling tools like search_docs or get_paper. An agent can tell what this tool retrieves without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly routes the agent to get_facets for obtaining facet values and tells it to pass them via filter_query, which is a genuine usage instruction. It lacks explicit when-not guidance or alternatives (e.g., when to prefer search_docs), so it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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Instructions

Input Schema

Schema Changelog

TDQS

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