gemini-cli-extensions/spanner
claude-codeSkills for Spanner
Spanner agent skills are an open-source Gemini CLI extension from Google that let AI coding agents explore schemas and run SQL on Cloud Spanner using natural language. Think of it as a database co-pilot you install into Claude Code, Antigravity, or Codex.
Our Review
Maintained by Google as part of its growing family of database agent extensions -- alongside BigQuery, AlloyDB, Cloud SQL, and Firestore skills under the same gemini-cli-extensions org. It wraps Cloud Spanner operations behind MCP Toolbox so any supported agent can read schemas and run queries by description rather than by hand-writing SQL.
What Spanner adds to your AI agent:
- •Natural-language SQL ask "how many orders shipped last week" and the agent writes and runs the googlesql query for you.
- •execute_sql and execute_sql_dql two dedicated skills for running DML (inserts, updates, deletes) and DQL (selects) against your database.
- •list_tables returns detailed schema as JSON, including columns, constraints, and indexes, in simple or detailed output.
- •list_graphs inspects Spanner property graphs, listing node tables, edge tables, labels, and property declarations.
- •Code generation ask the agent to generate data classes and snippets from your table schemas.
- •googlesql and postgresql dialects set SPANNER_DIALECT to match your database, defaulting to googlesql.
Compatibility:
The skills install into three hosts: Antigravity (CLI v1.6.0+ or 2.0), Claude Code (v2.1.94+), and Codex (v0.117.0+). Claude Code users add the marketplace with /plugin marketplace add and run /plugin install spanner@spanner-marketplace; other hosts clone the repo and copy the skill folders. You need a Google Cloud project with the Spanner API enabled, Application Default Credentials, and the Database Reader plus Database User IAM roles. Configure it with the SPANNER_PROJECT, SPANNER_INSTANCE, and SPANNER_DATABASE environment variables.
Limitations:
The project is in beta (pre-v1.0) and the maintainers warn of possible breaking changes before the first stable release, so pin to a tag like 0.3.1 rather than tracking main. It only works with Google Cloud Spanner, not other databases, and assumes you already have a provisioned instance and correct IAM. At 18 GitHub stars it is early and lightly battle-tested compared with mature general-purpose database MCP servers.
Our Verdict
Spanner agent skills are a clean, official way to put Google Cloud Spanner inside your AI coding agent, and at version 0.3.1 they already cover the daily database tasks that matter: schema discovery, querying, and graph inspection. Because Google maintains it under the same org as its BigQuery and AlloyDB extensions, it is a safe bet if you are already on Google Cloud.
For Vibe Builders, the appeal is removing the SQL wall. You can ask your agent to list tables, explain a schema, or pull a report in plain English instead of memorizing googlesql syntax, which makes a managed enterprise database far more approachable.
For Developers, the value is keeping Spanner work inside the editor loop. The list_tables and list_graphs skills return structured JSON you can act on, and code generation from schemas cuts boilerplate when wiring a data layer.
Skip it if you do not run Cloud Spanner, or if you need a production-hardened, multi-database tool today -- a beta pre-v1.0 release with 18 stars carries breaking-change risk, so weight that against how much you rely on it.
Frequently Asked Questions
What is the Spanner Gemini CLI extension?
It is a set of open-source agent skills from Google that let AI coding agents interact with Google Cloud Spanner databases using natural language. Packaged as a Gemini CLI extension and a Claude Code plugin, it lets you explore schemas, run SQL queries, inspect property graphs, and generate code without leaving your agent. It is maintained in the gemini-cli-extensions GitHub organization.
Is the Spanner extension free and open-source?
Yes. The Spanner agent skills are released under the Apache-2.0 license, so they are free to use and modify. As of 2026 the project sits at version 0.3.1 and is in beta (pre-v1.0), which means the code is open but the maintainers warn of possible breaking changes before a stable release. You still pay Google Cloud for the underlying Spanner instance you connect to.
Which AI agents and clients support the Spanner skills?
Three hosts are supported: Antigravity (CLI v1.6.0 or higher, or Antigravity 2.0), Claude Code (v2.1.94 or higher), and Codex (v0.117.0 or higher). Claude Code installs it through its plugin marketplace, while Antigravity and Codex install it by cloning the repository and copying the skill folders. The skills are backed by MCP Toolbox under the hood for the actual database connection.
What can the Spanner agent skills actually do?
The extension ships four core skills: execute_sql for DML statements, execute_sql_dql for DQL select queries, list_tables for detailed table schema as JSON, and list_graphs for property-graph structure. Beyond running queries, you can ask the agent to explore your schema in plain English and generate data classes from your tables. It supports both the googlesql and postgresql dialects via the SPANNER_DIALECT setting.
What do I need to install and use the Spanner extension?
You need a Google Cloud project with the Spanner API enabled, Application Default Credentials configured, and the Cloud Spanner Database Reader and Database User IAM roles. Set the SPANNER_PROJECT, SPANNER_INSTANCE, and SPANNER_DATABASE environment variables, then install the skills for your agent. In Claude Code that means running the plugin marketplace add and install commands; other agents clone the repo and copy the skill folders into place.
What is spanner?
Spanner agent skills are an open-source Gemini CLI extension from Google that let AI coding agents explore schemas and run SQL on Cloud Spanner using natural language. Think of it as a database co-pilot you install into Claude Code, Antigravity, or Codex.
How do I install spanner?
Visit the GitHub repository at https://github.com/gemini-cli-extensions/spanner for installation instructions.
What license does spanner use?
Check the repository for license details.
What are alternatives to spanner?
Explore related tools and alternatives on My AI Guide.
Open source: source code publicly visible
Anyone can inspect exactly what this repo does on GitHub before using it.
Reviewed by My AI Guide for relevance, quality, and active maintenance before listing.
Install in Claude Code:
/install spanner