feat: add --output-format json flag to goose run command

[sheikhlimon]

Summary

This pull request implements the requested --output-format json flag for the goose run command, enabling structured JSON output for programmatic parsing. The feature allows users to parse tool calls and responses programmatically, similar to Claude Code's --output-format json functionality.

Key changes:

• Added --output-format flag with default value "text" (preserving backward compatibility)
• Implemented JSON output mode that outputs structured data with messages, tool calls, responses, and metadata
• Created JSON-serializable data structures for the output format
• Modified message processing to capture data in JSON format when requested
• Maintained all existing functionality while adding the new feature

Type of Change

• Feature
• Bug fix
• Refactor / Code quality
• Performance improvement
• Documentation
• Tests
• Security fix
• Build / Release
• Other (specify below)

Testing

• Manual Testing: Verified the feature works by running goose run --text "..." --output-format json and confirming structured JSON output
• Backward Compatibility: Tested goose run --text "..." --output-format text and default behavior to ensure existing functionality preserved
• CLI Integration: Verified the new flag appears in --help output and accepts valid values
• Build Verification: Confirmed the project compiles successfully with cargo build and cargo check
• Error Handling: Tested that the command still works correctly with various input scenarios

The changes have been manually validated to work as specified in the feature request while maintaining all existing functionality.

Related Issues

Relates to #4419

[Copilot]

Pull Request Overview

This PR adds JSON output format support to the Goose CLI, allowing users to receive structured JSON responses instead of text-based output. The feature is controlled via a new --output-format command-line argument that accepts either "text" (default) or "json" values.

Key changes:

• Added output_format field to session configuration, builder, and CLI arguments
• Introduced JSON data structures (JsonOutput, JsonMessage, JsonToolCall, JsonToolResponse, JsonMetadata) for structured output
• Modified message processing to capture and serialize messages, tool calls, and responses when JSON format is requested
• Suppressed text-based rendering when JSON output is active

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
crates/goose-cli/src/session/mod.rs	Added JSON structs, output_format field to CliSession, and logic to collect/serialize session data as JSON
crates/goose-cli/src/session/builder.rs	Added output_format field to SessionBuilderConfig with default implementation, updated builder to pass format through
crates/goose-cli/src/cli.rs	Added --output-format CLI argument with default value "text"
crates/goose-cli/src/scenario_tests/scenario_runner.rs	Updated CliSession::new call to include default "text" output format
crates/goose-cli/src/commands/bench.rs	Updated SessionBuilderConfig to include default "text" output format

Comments suppressed due to low confidence (1)

crates/goose-cli/src/session/mod.rs:1159

• Similar to Comment 6, this progress_bars.log call at line 1159 is not guarded by output_format check, potentially contaminating JSON output with text messages in non-JSON mode contexts.

                                        progress_bars.log(&formatted_message);

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[Copilot]

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[angiejones]

thanks for your contribution! please be sure to sign the DCO

[sheikhlimon]

I've addressed all the Copilot AI suggestions from the recent code review. Happy to address any feedback.

[sheikhlimon]

thanks for your contribution! please be sure to sign the DCO

Thank you for reviewing and pointing this out.

[alexhancock]

I love the idea and am surprised we don't support some form of this already. Left a question

[alexhancock]

Were you adhering to anything that has become a standard for representing agent exchanges in json form?

Given that goose models ToolRequest and ToolResponse as message content, I think it should reflect these in the list of messages, not as separate lists.

goose/crates/goose/src/conversation/message.rs

Lines 134 to 135 in 37e1bb1

	ToolRequest(ToolRequest),
	ToolResponse(ToolResponse),

Does that make sense?

[sheikhlimon]

My bad.. I wasn't following any particular standard.. I'm a bit new to goose and rust. Seemed like a simple fix. I play around with json and flags stuff from time to time.. Anyway, I'll refactor this to serialize the the complete Message objects (including all MessageContent variants like ToolRequest/ToolResponse) directly in the messages array, rather than splitting them.
Just to clarify should the JSON output serialize the messages as-is using the existing serde derives on Message and MessageContent, or would you prefer a flattened/simplified format for the JSON output specifically?

[alexhancock]

"serialize the messages as-is" is what I would do

[sheikhlimon]

Done. Messages now should serialize as-is

[alexhancock]

Working nicely for me!

🐚 10:44:23 ~/Development/goose main $ ./target/debug/goose run --output-format json -t "hello"
starting session | provider: databricks model: databricks-claude-sonnet-4-5
    session id: 20251104_12
    working directory: /Users/alexhancock/Development/goose
{
  "messages": [
    {
      "id": null,
      "role": "user",
      "created": 1762271082,
      "content": [
        {
          "type": "text",
          "text": "hello"
        }
      ],
      "metadata": {
        "userVisible": true,
        "agentVisible": true
      }
    },
    {
      "id": "msg_bdrk_01GxCtrw1WHBM2oMXss8m9AF",
      "role": "assistant",
      "created": 1762271084,
      "content": [
        {
          "type": "text",
          "text": "Hello! 👋 \n\nI'm **goose**, an AI agent created by Block. I'm here to help you with a wide range of tasks, from coding and development work to answering questions and solving problems.\n\nI have access to several tools and capabilities:\n- **Code analysis and editing** - I can view, edit, and analyze code files\n- **Shell commands** - I can run commands in your terminal\n- **Chat recall** - I can search through our past conversations\n- **Extension management** - I can discover and enable additional extensions for specialized tasks\n\nSince I can see you're in the `/Users/alexhancock/Development/goose` directory, I'm ready to help with the goose project itself if needed, or anything else you'd like to work on!\n\nWhat would you like to do today?"
        }
      ],
      "metadata": {
        "userVisible": true,
        "agentVisible": true
      }
    }
  ],
  "metadata": {
    "total_tokens": 7066,
    "status": "completed"
  }
}

[sheikhlimon]

Getting a clippy error in goose-mcp/src/computercontroller/mod.rs:1119 (unrelated to my changes). Should I fix it here or skip?

[alexhancock]

@sheikhlimon yeah those resolutions seem fine

[sheikhlimon]

Getting a clippy error in goose-mcp/src/computercontroller/mod.rs:1119 (unrelated to my changes). Should I fix it here or skip?

@alexhancock ok.. do i create an issue for this or are you aware already? this could be created by running cargo clippy --package goose-mcp -- -D warnings

[alexhancock]

@sheikhlimon we'll deal with the other computercontroller thing

[alexhancock]

thanks!