ADFA-5410 | Implement native tool calling for Gemini and OpenAI agents

[jatezzz]

Description

This PR migrates the Gemini and OpenAI agent backends to use their native function-calling APIs instead of relying on plain text tool call envelopes. This addresses the issue where LLMs produced malformed text payloads (such as unescaped quotes or newlines) which caused valid tool calls to be skipped or silently fail. By correctly declaring tool schemas and updating the system prompts to stop teaching the <tool_call> syntax when native calling is available, the agents can now execute actions reliably.

Details

• Added ToolCallingBackend capabilities to both GeminiBackend and OpenAiBackend.
• Introduced GeminiToolProtocol and OpenAiToolProtocol to manage provider-specific JSON schemas, declarations, and chunk parsing.
• Updated ToolCallExtractor to diagnose and report malformed or truncated tool replies, preventing the agent loop from incorrectly reporting success.
• Added ToolCodeParser to intercept and extract tool calls from Gemini's undocumented default_api.<tool>(...) fallback syntax.
• Implemented ToolSchema to standardise and provide structured parameter schemas for all tool handlers (e.g., AddDependencyHandler, CreateFileHandler).
• Added ProjectLayout context to the system prompt to explicitly inform the agent of the module structure, significantly reducing wasted list_files steps.

OpenAI

Screen_Recording_20260904_104112_Code.on.the.Go.mp4

Gemini API

Screen_Recording_20260904_105334_Code.on.the.Go.mp4

Ticket

ADFA-5410

Observation

The AgentLoop has also been updated to halt accurately when tool calls are unparsable or abandoned, providing specific diagnostic messages to the user rather than failing silently.

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