feat: Enable json_schema enforcement for reliable structured outputs

- Changed response_format from json_object to json_schema
- Added full PRReview schema with GBNF grammar enforcement
- Tested and verified working with codestral:22b on 4400+ token PR
- Updated docker-compose.yml with clean placeholder values

Author: Tobias J. Endres

docker-compose.yml

@@ -1,7 +1,4 @@
-# PR-Agent Docker Compose Configuration
-# 
-# This compose file is configured for use with local Ollama models.
-# Copy this file and customize the environment variables for your setup.
+# PR-Agent Docker Compose for Local Ollama
 #
 # Usage:
 #   docker compose run --rm pr-agent --pr_url="https://your-git-host/owner/repo/pulls/1" review
@@ -10,68 +7,19 @@ services:
   pr-agent:
     image: ghcr.io/tobend/pr-agent:latest
     container_name: pr-agent
-    
-    # Mount your local configuration (optional)
-    # volumes:
-    #   - ./.pr_agent.toml:/app/.pr_agent.toml:ro
-    
     environment:
-      # =============================================================
-      # REQUIRED: Git Provider Configuration
-      # =============================================================
+      # Git Provider (gitea, github, gitlab)
+      - CONFIG.GIT_PROVIDER=gitea
 
       # Gitea Configuration
       - GITEA.URL=https://your-gitea.example.com
       - GITEA.PERSONAL_ACCESS_TOKEN=${GITEA_TOKEN}
 
-      # GitHub Configuration (uncomment if using GitHub)
-      # - GITHUB.USER_TOKEN=${GITHUB_TOKEN}
-      
-      # GitLab Configuration (uncomment if using GitLab)
-      # - GITLAB.URL=https://gitlab.com
-      # - GITLAB.PERSONAL_ACCESS_TOKEN=${GITLAB_TOKEN}
-      
-      # =============================================================
-      # REQUIRED: LLM Configuration (Ollama)
-      # =============================================================
-      
-      # Ollama endpoint (use /v1 for OpenAI-compatible API)
+      # Ollama Configuration
       - OPENAI.API_BASE=https://your-ollama.example.com/v1
       - OPENAI.KEY=dummy
 
-      # Model selection - recommended models for PR review:
-      #   - codestral:22b (best results)
-      #   - qwen2.5-coder:14b (good)
-      #   - mistral:latest (lightweight)
+      # Model (codestral:22b works well with json_schema)
       - CONFIG.MODEL=openai/codestral:22b
-      
-      # =============================================================
-      # OPTIONAL: Model Configuration
-      # =============================================================
-      
-      # Token limit for custom models not in PR-Agent's default list
       - CONFIG.CUSTOM_MODEL_MAX_TOKENS=8192
-      
-      # Temperature: 0 = deterministic, higher = more creative
       - CONFIG.TEMPERATURE=0
-      
-      # =============================================================
-      # OPTIONAL: Advanced LiteLLM Settings
-      # =============================================================
-      
-      # Enable JSON schema validation (recommended)
-      - LITELLM.ENABLE_JSON_SCHEMA_VALIDATION=true
-      
-      # Override response_format if needed (already set as default in this fork)
-      # - LITELLM.EXTRA_BODY={"response_format":{"type":"json_object"}}
-      
-      # =============================================================
-      # OPTIONAL: PR Review Customization
-      # =============================================================
-      
-      # Add custom instructions for the reviewer
-      # - PR_REVIEWER.EXTRA_INSTRUCTIONS=Focus on security and performance
-      
-      # Disable specific review features
-      # - PR_REVIEWER.REQUIRE_TESTS_REVIEW=false
-      # - PR_REVIEWER.REQUIRE_SECURITY_REVIEW=false

pr_agent/settings/configuration.toml

@@ -345,8 +345,9 @@ failure_callback = []
 service_callback = []
 # model_id = "" # Optional: Custom inference profile ID for Amazon Bedrock
 
-# Ollama/local LLM support: Force JSON output to prevent markdown wrapping
-extra_body = '{"response_format":{"type":"json_object"}}'
+# Ollama/local LLM support: Force structured output with PRReview schema enforcement
+# Uses GBNF grammars to ensure exact schema compliance (Ollama 0.5+)
+extra_body = '{"response_format":{"type":"json_schema","json_schema":{"name":"PRReview","schema":{"type":"object","properties":{"review":{"type":"object","properties":{"estimated_effort_to_review_[1-5]":{"type":"integer"},"score":{"type":"integer"},"relevant_tests":{"type":"string"},"security_concerns":{"type":"string"},"key_issues_to_review":{"type":"array","items":{"type":"object","properties":{"relevant_file":{"type":"string"},"issue_header":{"type":"string"},"issue_content":{"type":"string"},"start_line":{"type":"integer"},"end_line":{"type":"integer"}}}}},"required":["estimated_effort_to_review_[1-5]","score","relevant_tests","key_issues_to_review","security_concerns"]}},"required":["review"]}}}}'
 
 [pr_similar_issue]
 skip_comments = false