feat(agents): add support for remote agents and multi-agent TOML files

[adamfweidman]

Summary

This PR enables the discovery and registration of remote agents (via A2A) defined in TOML files. It also introduces support for defining multiple remote agents within a single TOML file using the [[remote_agents]] array syntax.

Details

• Remote Agent Support: Implemented schema validation for agents defined with an agent_card_url.
• Multi-Agent Config: Added support for [[remote_agents]] blocks to define multiple remote agents in
  one file.
• Flexible Syntax:
  • description is optional for remote agents (defaults to a placeholder).
  • kind defaults to "remote" and can be omitted within [[remote_agents]] blocks.

Related Issues

Fixes: #15094

How to Validate

• Enabled experimental agents with "experimental": { "enableAgents": true } in your settings.json
• Add

kind = "remote"
name = "remote-tester"
description = "A remote testing agent (A2A)"
agent_card_url = "https://example.com/agent-card.json"

to .gemini/agents/remote-agent-example.toml

• run npm run start -- --debug and confirm AgentRegistry] Registered remote agent 'remote-tester'... appears in debug console

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

[gemini-code-assist]

Summary of Changes

Hello @adamfweidman, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the agent management system by introducing support for remote agents and allowing the definition of multiple agents within a single TOML configuration file. These changes provide greater flexibility in how agents are discovered, registered, and configured, paving the way for more dynamic and scalable agent-based applications.

Highlights

• Remote Agent Support: Introduced the capability to define and register remote agents using TOML files, enabling discovery via A2A (Agent-to-Agent) communication.
• Multi-Agent TOML Files: Added support for defining multiple agents within a single TOML file using the [[agents]] array syntax, streamlining configuration.
• TOML Parsing Enhancements: Refactored the TOML loader to differentiate between local and remote agent definitions, validate remote agent properties like agent_card_url, and parse multiple agent entries from a single file.
• Debug Logging for Remote Agents: Implemented debug logging within the AgentRegistry to provide visibility when remote agents are successfully registered, including their associated agent card URL.

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[gemini-code-assist]

Code Review

This pull request introduces support for remote agents and defining multiple agents within a single TOML file. The changes are well-structured, introducing new Zod schemas for validation and updating the TOML loading logic to handle both single and multiple agent definitions. The addition of tests for the new functionality is also good. I've found one potential issue regarding the Zod schema validation that could lead to user confusion, which I've detailed in a specific comment. Otherwise, the implementation looks solid.

[github-actions]

Size Change: +2.41 kB (+0.01%)

Total Size: 22 MB

Filename	Size	Change
./bundle/gemini.js	22 MB	+2.41 kB (+0.01%)

ℹ️ View Unchanged

Filename	Size
./bundle/sandbox-macos-permissive-closed.sb	1.03 kB
./bundle/sandbox-macos-permissive-open.sb	890 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB
./bundle/sandbox-macos-restrictive-closed.sb	3.29 kB
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB

_{compressed-size-action}

[adamfweidman]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces support for remote agents and defining multiple agents within a single TOML file. A high-severity Server-Side Request Forgery (SSRF) vulnerability has been identified due to insufficient validation of the agent_card_url in remote agent definitions, which could allow an attacker to scan internal networks or access sensitive cloud metadata. Stricter URL validation is recommended to mitigate this risk. Additionally, while the changes are well-structured and use Zod for validation, consider improving the accuracy of the TypeScript type definitions to better match post-validation data structures for enhanced type safety.

[adamfweidman]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces support for remote agents and multi-agent TOML files, which is a great enhancement. The implementation is well-structured with clear separation of concerns using new types and Zod schemas for validation. The accompanying tests are thorough and cover the new functionality well. I have one suggestion to improve the robustness of the TOML parsing logic for single-agent files to make it more user-friendly. Additionally, there's a minor discrepancy in the pull request description regarding the TOML key for multi-agent files ([[agents]] vs. [[remote_agents]] in code), which might be worth clarifying.

[adamfweidman]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces excellent new functionality for defining remote agents and multiple agents within a single TOML file. The implementation is robust, leveraging Zod for schema validation and providing clear error messages. The accompanying tests are thorough and cover the new features and edge cases well. I have one suggestion to improve the maintainability of the error formatting logic to make it more resilient to future refactoring.