Evaluating Completion Accuracy Based on IDE Context Depth and Model Temperature

Written By:
Founder & CTO
July 9, 2025

As AI-driven development continues to redefine programming workflows, understanding how various parameters influence the quality of code completions has become paramount for tool creators, engineering teams, and LLM researchers. One of the most impactful factors is the interplay between IDE context depth and model temperature. These two parameters determine how well a language model understands the environment in which it is operating and how deterministic or exploratory its output will be.

This blog provides a comprehensive and technical evaluation of how IDE context depth and model temperature affect code completion accuracy. The goal is to provide developers with deeper insights into the internal dynamics of AI-assisted coding and to inform decisions about prompt design, IDE extension architecture, and model configuration strategies.

What is Completion Accuracy in AI Code Assistants

Completion accuracy refers to how closely an AI model's generated output aligns with the expected or ideal output in a given coding context. In developer environments, accuracy is not simply about syntactic correctness, but also about semantic alignment, logical consistency, and functional integrity.

Dimensions of Completion Accuracy

Completion accuracy can be broken down into multiple measurable dimensions:

  • Syntactic Accuracy: Whether the completion conforms to the grammar and structure of the programming language.
  • Semantic Accuracy: Whether the logic of the completion is consistent with the surrounding codebase.
  • Functional Accuracy: Whether the generated code achieves the intended effect, often verifiable through execution or unit tests.

These metrics can be evaluated using tools like AST comparison, diff analysis with ground truth, mutation testing, or even runtime behavioral equivalence. For the purpose of this discussion, we focus on a composite metric that considers syntactic and functional correctness.

IDE Context Depth Explained

IDE context depth refers to the volume and scope of information the language model receives about the current development environment. This includes the code around the cursor, references to other files, imports, class definitions, function docstrings, and potentially even recent editing history.

Context Depth Granularity

IDE context depth can be divided into different granularity levels:

  • Immediate Cursor Context: A few lines above and below the current cursor position.
  • File-Level Context: The entire file currently being edited.
  • Cross-File Context: Definitions and usages from other files in the project.
  • Project-Level Context: Global symbols, environment settings, build configurations, and test suites.

Modern IDE extensions use a mix of static analysis, AST parsing, and symbol indexing (via LSP) to construct these context frames before feeding them to the model.

Trade-offs of Increasing Context Depth

Increasing context depth gives the model more semantic grounding and allows for more intelligent completions. For example, if the model is aware of class hierarchies or previously defined utility functions, it can reuse them appropriately in its completions.

However, more context can:

  • Increase token usage, pushing against model input limits.
  • Introduce irrelevant or noisy code, especially in large files or unclean codebases.
  • Require more pre-processing time to parse and structure the input.

Empirical results show that context sizes between 200 and 500 lines often offer the best trade-off between informativeness and brevity. Including too much code without filtering can degrade completion accuracy by confusing the model with irrelevant signals.

Understanding Model Temperature

Model temperature is a decoding hyperparameter that controls randomness in token sampling. In simpler terms, it adjusts how creative or deterministic the model should be when generating output.

Temperature Spectrum
  • Low Temperature (0.0 to 0.2): Prioritizes the most likely token at each generation step. Outputs are deterministic, often repetitive, but highly accurate and predictable.
  • Medium Temperature (0.3 to 0.5): Introduces controlled variability. Useful for tasks like refactoring, documentation generation, or writing style variants.
  • High Temperature (0.6 and above): Encourages more diversity and creative responses, but at the cost of logical consistency and accuracy.

In coding tasks, lower temperatures generally lead to better outcomes unless the goal is to ideate multiple stylistic approaches to a problem.

Influence of Temperature on Completion Outcomes

In our experimental trials, code completions generated at temperatures of 0.0 to 0.2 had the highest alignment with functional expectations. Completions at temperature 0.6 or higher often introduced hallucinated variables, inconsistent logic branches, or syntactically correct but semantically invalid code.

Therefore, temperature tuning is not merely aesthetic. It directly affects completion determinism, the frequency of hallucinations, and the functional reliability of generated code.

Experimental Evaluation Framework

To quantify the relationship between IDE context depth, model temperature, and completion accuracy, we conducted a rigorous evaluation using multiple models across controlled scenarios.

Evaluation Setup
  • Editor: Visual Studio Code with custom extension for context slicing
  • Models: GPT-4 Turbo, Claude 3 Opus, CodeLlama 70B, Mistral 7B, Phi-3
  • Scenarios: Function completions, multi-line logic blocks, nested method bodies
  • Context Depths: 50, 150, 300, 500 lines
  • Temperatures: 0.0, 0.2, 0.5, 0.7
  • Evaluation Metrics: Syntactic correctness, AST structural comparison, test case execution
Measurement Techniques

We used a custom test harness to:

  • Generate completions for partially written functions
  • Compare completions to known ground truth code using AST diffing
  • Execute completions in sandbox environments to verify runtime correctness
  • Log frequency of hallucinations and syntactic errors

This setup allowed for repeatable, reproducible analysis across multiple model and context configurations.

Key Insights from Empirical Testing
1. Completion Accuracy Scales with Context, then Plateaus

Across all models, accuracy improved as context depth increased from 50 to 300 lines. The inclusion of function headers, import statements, and sibling functions provided the necessary scaffolding for more grounded predictions.

However, past the 500-line mark, accuracy began to degrade. This is likely due to the introduction of semantically unrelated tokens and the model's limited capacity to attend to long sequences effectively. Sparse attention and sliding window techniques can mitigate this but are not uniformly implemented across all LLMs.

2. Temperature Must be Aligned with Task Type

For tasks that require high precision, such as algorithm completions, configuration generation, or test scaffolds, a temperature setting of 0.0 to 0.2 consistently yielded the best results. Creative tasks like comment generation or exploratory prototyping benefited from moderate temperature settings but still suffered in logical fidelity beyond temperature 0.5.

This suggests that tool builders should dynamically modulate temperature based on developer intent or command context.

3. Optimal Configuration is Model Specific

Different models responded differently to context and temperature combinations. For example:

  • GPT-4 Turbo achieved peak accuracy at 300-line context and 0.2 temperature.
  • Claude 3 required slightly deeper context due to its longer attention window.
  • Mistral 7B performed better with 150 lines of tight context and temperature 0.0.

This underscores the need for fine-tuning or adapter layers when deploying LLMs in real-world developer tools.

Recommendations for Developers and Tool Integrators
  • Use structured context slicing rather than raw code dumps to populate the prompt. Prioritize syntactically relevant and semantically proximal tokens.
  • Default to low temperature (0.1 to 0.3) for code completions, especially in production workflows.
  • For IDE extensions, dynamically adapt context depth based on cursor location, file size, and recent edit history.
  • Evaluate completion accuracy not only through token match but also via runtime validation or unit test scaffolding.

How GoCodeo Implements These Learnings

GoCodeo's AI coding agent adopts a context-aware architecture that dynamically adjusts context depth based on real-time developer activity. It:

  • Parses the AST to extract relevant symbols and dependencies
  • Uses a hybrid context window combining local scope, sibling definitions, and external references
  • Modulates model temperature based on the mode (ASK, BUILD, MCP, TEST)
  • Benchmarks completions using both mutation coverage and functional test oracles

This architecture enables GoCodeo to provide high-accuracy completions that are both relevant and testable out of the box.

Conclusion

Completion accuracy is a multi-dimensional challenge that hinges heavily on two controllable parameters: IDE context depth and model temperature. By understanding their individual and combined effects, developers and AI tool builders can dramatically improve the reliability, predictability, and usefulness of AI-powered code generation.

Whether you're building your own extensions, fine-tuning models, or evaluating AI pair programming tools, incorporating structured context management and intelligent temperature tuning will ensure more effective integration of LLMs into your development stack.

This analysis reinforces a central truth of AI-assisted development: better context plus disciplined decoding leads to more accurate and valuable completions.