Gtex

Tissues

tissues

Read-onlyIdempotent

GTEx Portal (Genotype-Tissue Expression project) — the catalogue of human tissue sites GTEx sampled, such as Liver, Whole_Blood and Brain_Cortex. Returns each tissue's tissueSiteDetailId, display name, parent tissue site, RNA-seq and genotype sample counts and colour code; that id is the spelling every other GTEx expression and eQTL tool expects. Answers which human tissues GTEx covers and how a tissue id is spelled.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

Changed2 schema fields changedMay 22, 2026

addedInput schema / examples
```
Added value: +[
+  {}
+]
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "description": "List of available tissues in GTEx",
+  "type": "object"
+}

First observedMay 18, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds meaningful context by specifying the exact return contents and clarifying that the tool serves as a lookup for tissue IDs, without contradicting any annotations.

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?

The description is two well-structured sentences, front-loaded with the GTEx context and immediately covering the return data and use case. Every word adds value; no filler or redundancy.

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

Completeness5/5

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

With no parameters and an output schema present, the description provides complete context: what the tool does, what it returns, and why the returned ID is important for downstream tools. It is self-contained for the intended use case.

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?

There are zero parameters, so the baseline is 4. The description adds useful context about the output and purpose, which is sufficient given that there is nothing to document about inputs.

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?

The description clearly states it provides a catalogue of GTEx tissue sites and returns specific fields (tissueSiteDetailId, display name, parent tissue site, sample counts, colour code). It distinguishes itself from sibling tools by focusing solely on tissue metadata and the canonical spelling of tissue IDs.

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?

It explicitly mentions that the tissue ID returned is what every other GTEx expression and eQTL tool expects, which signals when this tool should be consulted. It also states it answers which tissues GTEx covers, but it does not name alternative tools or provide direct exclusions.

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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