Google Antigravity release notes: CLI 1.1.15 keeps multiple JSON prompts in one session

Google Antigravity CLI 1.1.15, published on August 19, can accept multiple prompts as a continuous JSON stream. The --input-format stream-json flag reads one newline-delimited JSON prompt from standard input per line and runs each message as a new turn in the same conversation. A driver can therefore keep context without restarting the command for every turn.

NDJSON means newline-delimited JSON: each line is a complete JSON object. Google also says the new input format requires --output-format stream-json, which emits machine-readable events while the agent works.

Source: Google Antigravity CLI 1.1.15 release notes.

Google Antigravity release notes: one stream, one conversation

The verified invocation shown by the 1.1.15 CLI help is:

agy --print --input-format stream-json --output-format stream-json

The input stream keeps one conversation open and runs one turn per message. The output stream starts with an init event, continues with step_update, and ends each run with a result. Google's current documentation describes the output events in detail. The 1.1.15 release notes confirm the input flow but do not yet publish a complete schema for each input object. Check agy --help in the installed version before building the driver.

Sources: Google Antigravity CLI 1.1.15 release notes. Google Antigravity: Headless mode.

The release also fixes corrupted non-ASCII characters in streamed text. The correction applies to both the interactive display and --output-format stream-json, including Swedish, Norwegian, and Danish text.

Source: Google Antigravity CLI 1.1.15 release notes.

Custom-agent rules become more selective

CLI 1.1.14 consolidated personal-customization inheritance under inheritCustomizations. The switch decides whether a Markdown-defined agent adopts the user's skills, rules, plugins, subagents, and MCP servers. MCP, or Model Context Protocol, is the standard that lets an agent use external tools and data sources through a common interface.

In 1.1.15, agent frontmatter also gains a rules: key. An agent can name rule files that always apply instead of inheriting the entire rule tree. Plugins can likewise declare their rule files through a top-level rules.json.

Sources: Google Antigravity CLI 1.1.14 release notes. Google Antigravity CLI 1.1.15 release notes.

Short example: use the new Antigravity feature

Human step: Confirm that agy --version reports 1.1.15. Then start the driver with --input-format stream-json and --output-format stream-json. Send this instruction as one turn after the driver has opened the conversation:

Read the project without changing files. Summarize the architecture, list the three main test commands, and finish with the files you need to inspect in the next turn. Keep those paths in the conversation context.

A good result should:

• Name specific files and test commands from the project.
• Leave the workspace unchanged.
• End with a clear list for the next message in the same conversation.