openstack-mcp-server

List regions

list_regions

Read-onlyIdempotent

Retrieve Keystone regions for an OpenStack cloud, optionally scoped to a project and capped by a limit, to inspect available identity regions.

Instructions

List Keystone regions. Not paged.

Input Schema

Name	Required	Description	Default
`limit`	No	Maximum items to return (1-100, default 50).
`project_id`	No	Project ID to work in; omit for the default project. Allowed values are listed by get_scope.

Output Schema

Name	Required	Description
`items`	Yes
`limit`	Yes	Maximum number of items requested.
`complete`	Yes	True when no more items exist beyond this page.
`resource`	Yes	Resource type of the items.
`project_id`	Yes	Project whose session produced the list.
`next_marker`	No	Pass as marker to read the next page; null when complete or when the API has no marker paging.
`observed_at`	Yes	UTC time the list was read.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 30, 2026

TDQS

B3.2/5.0

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 covered. 'Not paged' is genuine added behavioral information, but it sits oddly next to a limit parameter capped at 100, leaving the actual truncation behavior ambiguous.

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

Conciseness4/5

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

Two short sentences, front-loaded with the resource, with no filler. The second sentence is terse to the point of ambiguity about how limit interacts with non-paging, but it is efficiently placed.

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

Completeness3/5

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

An output schema exists so return values need no explanation, and the schema covers both parameters. However, the 'Keystone regions' terminology is unexplained and 'not paged' conflicts with the presence of a limit, leaving a real behavioral question open for an agent deciding how many results to expect.

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

Parameters3/5

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

Schema coverage is 100%, so both limit (1-100, default 50) and project_id (omit for default project; values from get_scope) are fully documented in the schema. The description adds nothing about parameters, so the baseline 3 applies.

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

Purpose4/5

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

States a specific verb and resource ('List Keystone regions'), which is unambiguous against the sibling list_* tools that target subnets, ports, servers, etc. It does not explicitly name a sibling or contrast itself, but the resource noun alone is sufficient differentiation here.

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

Usage Guidelines2/5

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

There is no guidance on when to use this versus the sibling get_scope or the other listing tools, and no mention of the project_id scoping choice beyond what the schema says. The reader is left to infer usage entirely from the resource name.

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