json-streaming-console

A real-time terminal streaming parser and structured formatter for Newline-Delimited JSON (NDJSON) output emitted by CLI LLM tools, such as Google Antigravity CLI (agy) and Anthropic Claude Code (claude).

Built in Go using zerolog, json-streaming-console converts verbose raw streaming JSON envelopes into a readable, ANSI-colorized tabular console output. It is particularly useful for observing and debugging CLI agent behavior (tool calls, file access, token consumption, and intermediate steps) in real time.

Supported Formats

Format Flag (-format, -f)	Target Tool	Supported Stream Events
gemini (default)	Google Antigravity CLI (agy)	init, step_update (user_input, agent_response, tool), result, end
claude	Anthropic Claude Code CLI (claude)	system/init, assistant, content_block_delta, tool_use, tool_result, result, error

Column Layout

The output is formatted as a continuous single-pipe table:

[TIMESTAMP] | [LEVEL] | [EVENT] | [SESSION_ID:STEP] | [TEXT_DELTA |] [ATTRIBUTES...]

• TIMESTAMP: Event timestamp in RFC3339 format.
• LEVEL: Categorized severity level:
  • INFO (Green): Lifecycle milestones (INIT, RESULT, END).
  • WARN (Yellow): Active execution turns, step updates, tool invocations, and agent responses.
  • ERROR (Red): Execution failures and events reporting error states.
• EVENT: Granular event or step classifier (e.g. INIT, USER_INPUT, AGENT_RESPONSE, TOOL_USE, TOOL_RESULT, RESULT, END).
• SESSION_ID:STEP: Unique session/conversation ID combined with the turn step index (<id>:<step>). Defaults to <id>:- when step index is absent.
• TEXT_DELTA: Dedicated field displaying real-time streaming chunks of agent response text, separated cleanly by a trailing pipe (|). Omitted on non-text steps.
• ATTRIBUTES: Contextual key-value metadata (e.g. STATE:DONE, TOOL_NAME:VIEW_FILE, DURATION_SECONDS:3.2, STATUS:SUCCESS). Excludes redundant internal fields.

Output Examples

Output Example

2026-09-27T12:43:48+02:00 | INFO  | INIT           | 4D29D340...:- | cwd: C:\home\dev
2026-09-27T12:43:48+02:00 | INFO  | INIT           | 4D29D340...:- | model: gemini-2.5-pro
2026-09-27T12:43:48+02:00 | INFO  | INIT           | 4D29D340...:- | allowed tool: view_file
2026-09-27T12:43:48+02:00 | INFO  | INIT           | 4D29D340...:- | allowed tool: run_command
2026-09-27T12:43:48+02:00 | WARN  | USER_INPUT     | 4D29D340...:0 | STATE:DONE
2026-09-27T12:43:49+02:00 | WARN  | AGENT_RESPONSE | 4D29D340...:1 | I will inspect the code. | STATE:ACTIVE
2026-09-27T12:43:50+02:00 | WARN  | TOOL           | 4D29D340...:2 | STATE:ACTIVE TOOL_NAME:VIEW_FILE
2026-09-27T12:43:51+02:00 | INFO  | RESULT         | 4D29D340...:- | DURATION_SECONDS:3.2 STATUS:SUCCESS
2026-09-27T12:43:52+02:00 | INFO  | END            | 4D29D340...:- | INPUT_TOKENS:1500 OUTPUT_TOKENS:200 TOTAL_TOKENS:1700

Usage

This form defaults to Google Gemini's cli format.

agy --output-format stream-json "your prompt here" | json-streaming-console

By specifying the format explicitly it can be used for Claude Code also.

claude -p --output-format stream-json --verbose "your prompt here" | json-streaming-console -format claude

CLI Flags

Flag	Shorthand	Type	Default	Description
-format	-f	string	gemini	Streaming JSON parser format: gemini or claude

Requirements

• Go 1.25+
• Dependencies: github.com/rs/zerolog